The Northern Utah WebSDR Latest news and current issues

Recent events and resolved issues:

• 18 July, 2019.  Comment:
• Server upgrade by web hosting service:
• On the evening of Thursday, 18 July, 2019 at around 1800MT the "sdrutah.org" web pages were unavailable.  This situation was temporary - lasting less than an hour - as the Web hosting service upgraded the server from Ubuntu 14.x to 18.x.  No changes should be visible to the users upon completion of this upgrade.
• 5 July, 2019.  Comments:
• "Bug" fixes on new pages.
• Initially, with the new pages it was not possible to embed the frequency and mode with the URL, but that has been fixed now - we hope.  You can now include the frequency and mode if you like, as in:  http://sdrutah.org/websdr1.html?tune=7272lsb  - which will go to WebSDR #1 and tune to 7272 kHz, lower sideband.
• The redirect did not previously work with the Microsoft Edge browser:   It appears to do so now.
• The "buttons" on the WebSDR GUI (page) that sent you to another WebSDR server to cover a different band had been "kludged" to work with the new scheme - but they didn't really do what they were supposed to do - which was to send the user to the "new" web pages - because of the inability to embed the frequency and mode in the URL:  They do now!
• Low gain on the KiwiSDRs below 500 kHz.
• It has been observed that at frequencies below the AM broadcast band, the KiwiSDR is a bit "gain starved" - a result of the "Limited attenuation high-pass filter" that had previously been installed to prevent it from being overloaded on signals below 8 MHz.  At some future visit, this filter will be modified to "pass around" such frequencies.  For more information about this high pass filter, read the article "A Limited Attenuation High-Pass Filter for the KiwiSDR".  This article does not yet include information about the modification to allow the <500 kHz energy to pass through.
  
• 19 June, 2019.  Comments:
• Internet connectivity issues!
• The Internet connectivity has, at times, been suffering from jitter and delays - a likely result of ongoing issues with one of the wireless hops connecting the site.  To remedy this situation, we will be transitioning to a different Internet Service Provider.
  Because of this, there will be an interruption to this WebSDR system during the transition.  The exact timing of this change is yet to be determined:  Additionally, there may be the complication of this system needing to change its URL.  We will attempt to give as much notice as possible prior to this change.
  In the meantime, occasional drop-outs may be mitigated by increasing the buffering using the Audio Buffering drop-down menu just below the WebSDR's volume control.
• For more information about this change, please read this.
  
• Thank you for your patience.
  
• 14 May, 2019.  Comments:
• Site visit:
• "High split" preamplifier repaired:
• The "loss" of reception on the "20CW", "20PH", "17M", "15M", "12M", and "10M" bands was, as suspected, caused by damage to the amplifier common to all of these receivers.  This amplifier, based on a Gali-74+ MMIC, proved to be susceptible to what was, at the very least, a "close" lightning strike.  The MMIC was replaced and reception was restored on these receivers.
• In reality, none of these receivers suffered any damage and remote analysis had shown that these receivers were just really deaf - to the tune of 30-40dB or so.
  
• "160M" preamplifier repaired:
• The "160M" receiver was also preceded by one of these same Gali-74+ MMIC modules and this amplifier, too, was damaged by the same strike.  A replacement of this MMIC restored this device to normal operation.
• Additional lightning protection added:
• The above damage to the amplifiers occurred despite the fact that these were "downstream" of fairly heavy-duty gas discharge tubes and RF filtering - both of which would have served to greatly reduce the amount of transient energy from the strike - but it wasn't apparently enough for the MMIC amplifiers.  To prevent a similar failure in the future, a more "sensitive" protection device was added - one that has both a gas-discharge tube and high-current limiting diodes.
• It's worth noting that in the other signal paths, discrete transistor-based RF amplifiers - based on the venerable 2N5109 - are being used, and none of these suffered any damage, likely due to the fact that this rather rugged device can (briefly) handle several watts without damage.
• The Gali-74+ is used in some of the signal paths because of its lower noise figure (3 dB versus 6 dB) and higher gain (21 dB versus 17dB) than the 2N5109-based amplifiers.
• In the "High split" signal path (for 20-10 meters) these devices allow the receivers to "hear" the thermal noise floor more easily, particularly on 10 meters.
• Using one of these devices on 160 meters helps make up for the relative deafness of the receiver module (a SoftRock II Ensemble) that is being used and the fact that the main antenna, which is designed for 3-30 MHz coverage, has lower signal output at 160 meters than on 80/75 meters.
• 40 meter receiver modified:
• Previously, a single RF amplifier was used to feed both the "40CW" and "40PH"receivers - and internal to this module, the input signal was split two ways to feed the two softrock boards.  After this receiver had been built it was determined, during the construction of the modules for 80/75 and 20 meters, that the best performance was obtained by using separate amplifiers for each, individual softrock board - each amplifier following the outputs of the internal RF splitter:  Doing this greatly reduced the amount of local-oscillator crosstalk between the two receivers which can, in some cases, cause low-level spurious signals to appear in the presence of very strong signals.
• To this end, a pair of RF amplifiers - one for each receiver - was added to the existing circuitry, inside the receiver module's box.  This adds 3-4 dB to the noise figure of the receiver because these amplifiers are now subject to post-splitter loss, but this factor is unimportant on 40 meters owing to the naturally-high noise and signal levels.
• Reconfiguring this amplifier freed one of the "general purpose" amplifier blocks allowing us to replace a "temporary" amplifier that had been built for the 17 meter receiver, helping to clean up the layout a bit.
  
• Sound cards replaced:
• As noted in the 1 May entry, the USB sound cards that had been used for "40CW" and "40PH" failed - apparently succombing to the same fate as is common with Asus Xonar U5 and U7 sound cards.  These two cards - a U5 and U7 - were replaced with a pair of U7s.  The failed cards will be analyzed to attempt to determine a "fix".
• At the moment, the "40PH" receiver is still using a Xonar D1 which has someone inferior image rejection as compared to the U5 or U7 - but it was decided to do this in case a USB sound card fails (again!) so that the risk of losing coverage of 40 meter phone - one of the most popular bands - will be minimized.
• Turnbuckles secured:
• It had been observed on a previous visit that one of the guy wires on the recently-replaced deadman (on the tower supporting the log-periodic beam) had unscrewed itself - a clear result of our not having remembered to add "safety wires" to prevent this.  Because of the limited cable length, it had not been possible for a single individual to reconnect this without proper tools, but with several people on-hand for this visit we could, collectively, pull just hard enough to engage the turnbuckle threads.
• Safety wires have been run through all of the turnbuckles to assure that this will not happen again.  With the (temporary) loss of this cable, the integrity of the tower was in no real danger - but it needed to be taken care of, just the same!
  

• 8 May, 2019.  Comments:
• "When it rains, it pours - and flashes lightning!"
• "160M", "20CW", "20PH", "17M", "15M", "12M" and "10M" receivers offline.
• Due to an apparent lightning strike, the receivers listed above are offline (extremely deaf, actually).  This strike apparently wiped out two RF amplifiers in the signal path:  The one for the "160M" receiver, and another amplifier that provides gain for all amateur bands above 30 meters.
• In the meantime, the "AM-160M-120M" receiver can provide a degree of coverage for 160 meters.
• Unfortunately, there is no similar back-up for the 20-10 meter bands' receivers.
• It will likely take a site visit to restore operation and it is expected that this will occur in the next 3-5 days.  In theory, these amplifiers could be bypassed to restore some semblance of operation, but this is unlikely to happen before a "proper" site visit might occur.

• 1 May, 2019.  Comments:
• Sound card failures:
• Unrelated to other issues, it would appear that there has been a failure either in two of the three USB sound cards on WebSDR1, or something amiss with the USB interface on the motherboard.  In the past, we "lost" one of these sound cards in a similar manner:  Everything was fine until the system was restarted, at which point the sound card refused to operate at the higher speed (e.g. USB 2.0) necessary for full 192 kHz band coverage.
• In doing research, this type of failure has been documented elsewhere, so it is not unprecedented.
• As a "work-around", the "80CW" sound card is now being used for "40PH", restoring full coverage of the SSB segment of that band.  Unfortunately, image performance will suffer slightly because a "I/Q Balance" equalization could not be done - but this will go unnoticed in the majority of cases.
• The "80CW" and "40CW" are using the "failed" hardware, but since it can operate only at 48 kHz, the coverage of those bands is limited.
• For coverage of the missing 80CW and 40CW segments use the back-up "90-80M" and "41-40M" receivers on WebSDR3 in the meantime.
• A site visit to repair/replace the errant hardware will likely occur within a week of this date.
• Firefox issues revisited - Audio stream stopping when a new tab is opened in the browser:
• As noted below (see 8 April entry) there is a known problem with the Firefox browser:  Clicking on a link to open a new tab may cause the audio stream from the WebSDR to stop.
• This issue has been reported to Mozilla and it is believed that a "fix" is in the works.
• If the audio stops because you have opened a new tab, there is currently no known way to restart the audio short of refreshing the web page.  Unfortunately, this may reset the frequency/mode, requiring one to re-tune the radio.
• If at all possible, open a link using a "right click" and select "open a new tab":  For whatever reason this seems less likely to interrupt the audio stream.
  

For "less-recent" events, go farther down this page.

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Issues currently being investigated:

• Power Line noise:  There is an intermittent power line related noise that occasionally shows up - and we are working to resolve this issue - but the system's noise blanker seems to be able to remove most of it.  This noise is typically the worst on 80/75 meters, but it seems to disappear at night as the band opens up and the ionospheric noise submerges it.  Several poles have been identified

• Audio/system drop-outs:  There have occasionally been periods where the audio will drop and/or the waterfall will freeze briefly.  While this is most often a result of the user's computer (e.g. your computer!) getting busy, pre-empting the browswer's audio processing or congestion on your Internet congestion - particularly if you have Internet via Wireless, Satellite or phone - see "Miscellaneous Quirks", below for some causes and work-arounds.

• A "pop" in the audio and an accompanying change in signal level:  There appears to be an intermittent cross-connection on the antenna between a feed and guy wire that can cause noise in the received signals and levels to fluctuate during very windy periods on site - particularly on the lower (160, 80/75 and the 630M-AM-160M) bands.  A similar-sounding - but unrelated - issue (described below) exists with the AM demodulator.   Occasionally, this seems to be accompanied by an increase in intermodulation distortion from AM broadcast band signals - a problem that can affect the 75 Meter and lower-frequency bands.

• Occasional outages:  We are working to "neaten up" the installation so we occasionally have to take something off line to dress a cable, replace a connector, "permanentize" an installation.  Tasks like this will cause outages of several minutes duration.  Some work is also being done at one or more of the interim sites that provide the Internet connection that occasionally result in outages.

• Low-level switching supply "birdies":  With lots of computers comes the possibility of lots of QRM from them!  Fortunately, there are no "strong" birdies, but there are some that, if they happen to sweep across the frequency to which you are listening, will cause some mild annoyance.

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Miscellaneous quirks (e.g. "It's supposed to be that way!"):

• If the WebSDR is not on an active window on YOUR computer:  If the WebSDR is not the currently active window on your desktop, the computer will give it lower priority and this will make audio drop-outs/waterfall freezes more common.  The same thing can happen if your computer is "busy" doing something else, such as other programs, updates, incoming emails, etc.  The same is likely true with other platforms (phone, Mac, etc.)  The first thing that you should do if you experience drop-outs is to switch to the window running the WebSDR.  Don't forget that your own Internet connection/ISP can result in drop-out issues as well.  It has been observed that on a typical Windows machine, if the processor utilization is over 65-70%, you may experience occasional drop-outs due to delays in the operating system providing processor time to the code that produces the audio and draws the waterfall.

• Waterfall not updating when you switch to another window:  When the waterfall is not visible (that is, you have switched to a window and moved the one with the WebSDR in the background) it will stop - which makes sense if you can't see it.  What this means is that when you switch back to where the waterfall is again visible there will often be a clear line of demarcation between what the signals were when you switched away and when you switched back.

• Occasional burst of noise across the band correlated with strong signals:  This is sometimes the result of the noise blanker that is active on all bands being triggered by the peaks of the strongest signal(s) on the band.  This effect is most easily spotted on 40 meters during the daytime where there is one signal that is extremely strong - often on the leading edge at the beginning of a transmission - and the band is otherwise quiet.  This effect should not be confused with other things that cause similar-looking artifacts, such as static crashes from distant lighting storms or brief signals from ionospheric and ocean wave profilers.

• When listening to AM, a sudden "pop" in the audio:  It's not actually supposed to do this, but there a "quirk" (bug?) in the AM demodulator that can cause this to happen, occasionally.  It seems to happen mainly when the signal level changes very quickly due to QSB (fading) but is less likely to happen on very steady signals or those with only very slow QSB.  The only "fix" for this - if it becomes annoying - is to listen on USB or LSB and zero-beat the carrier.

• The bands on the "other" server aren't visible to me unless I go to that "other" server:  It is this way because there are several independent WebSDR servers.

If you notice some issues that are unrelated to those listed above feel free to use the contact info on the About page to let us know about it.

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"Less-recent" events and resolved issues:

• 29 April, 2019.  Comments:
• WebSDR system offline:
• The WebSDR system was offline for around a day due to some issues with the server - possibly caused by nefarious activity.  Because the main "WebSDR guy" (me!) happened to be on vacation when this happened, it was a day or so before one of our "alternate" operators noticed and restarted the system.
• "40CW" and "40PH" bands semi off-line - running at reduced bandwidth:
  
• Not directly related to the above issue, the sound cards for the "40CW" and "40PH" bands are refusing to initialize properly after a system restart.  This is a known hardware/software "bug", but it seems to show up only rarely.  At the very least, the server will need to be completely powered-down, requiring a site visit.
• The initial symptom of this was "cutting out" of the audio until these cards were reinitialized for 48 kHz bandwidth - but this has the side-effect of allowing only 1/4 of the previous band coverage.
• UNTIL THIS PROBLEM IS RESOLVED, please use the back-up "41-40M" receiver on WebSDR3.  While this receiver isn't quite as good as the normal receivers, it works nearly as well under most conditions.
  

• 8 April, 2019.  Comments:
• Audio stopping with Firefox when you make the browser busy:  We have become aware of an interesting (potential) issue with Firefox regarding audio:   Sometimes the audio stream will stop - and not restart - if, on your browser, you open a new tab, of if you have opened several tabs with the WebSDR running in the background and have done something in another window/tab that has momentarily caused your computer/browser to become busy.
• The easiest "fix" for this is to reload the web page which, unfortunately, is likely to reset the frequency/mode to which you are listening.  We don't have any other suggestions at this time.
• Little/no signal on KiwiSDR3 WebSDR3:  (Note:  I meant to write "KiwiSDR3" - there was no problem with WebSDR3).  It would appear that I didn't get the "RF Input" SMA connector tight when working on KiwiSDR3 which means that only the strongest signals show up at all.  One of our volunteers is likely to be in the area in the next couple days and will (hopefully) get time to drop by and take care of the problem.  Fortunately, only two of the least-used WSPR "bands" are on this receiver (the now-deprecated 80 meter frequency and one of the 60 meter frequencies) so not much is being missed.
  

• 2 April, 2019.  Comments:
• Local power outage:  The local utility is working on the lines and power to the site was lost at 0915.  Because we were informed of this ahead of time (one of the local power guys occasionally uses this WebSDR system) we were pre-positioned and put the site on generator power when it went out, running on UPS for only about 15 minutes, total.
• Because of the extended outage, we were on-site, tending the generator, taking advantage of the time we are here to do other work on the system, as noted below.
• Off in the distance we saw the power crews working on the lines that feed the site.  In speaking with one of the utility employees - who came by to make sure that everything had come back up - he said that they "... did a lot of work... replaced a lot of glass" meaning that more than just insulators were replaced.
  
• The power was restored at 1755 local time - an outage of  8-2/3 hours - a bit ahead of schedule despite the rather rainy, miserable weather.
• RTL-SDR identification script installed on WebSDR1:  We have finally installed the script on WebSDR1 that automatically identifies - via programmed serial number - which RTL-SDR dongle is to be used for which band.  
• This script had been installed on WebSDR2 and 3 a while ago, but WebSDR1 seemed always to be too busy to interrupt everyone and restart the system - but since there were warnings plastered all over the place today, we thought that it would be a good opportunity.
• This script solves the problem where it would matter which RTL-SDR dongle was plugged into which USB port - and how many dongles there were.  Because one must always use the same dongle for the same frequency band (because of RF filtering) it was a huge pain to make sure that all of the dongles got sorted out right:  This script eliminates all of that mess!
• 17 Meter coverage expanded:  The sound card previously used for this band had a sampling rate of only 96 kHz, which meant that a bit more than 4 kHz of this band (2-3 kHz ) was left off at each end.
• The new card has a 192 kHz sample rate, so the entire band - plus several 10s of kHz beyond the top and bottom - is now covered.
• Fully-covering 12 meters will require a bit of juggling of hardware, but since 17 meters is open far more often than 12 during this part of the solar cycle, 17 meters had priority.
• Log Periodic beam checked:  Despite a drizzle and a modest breeze, the 80 foot tower was scaled and leads were clipped to the bloody-end of the remaining coax at the top that connects to the massive 6-45 MHz log periodic beam (a Hy-Gain/U.S. Antenna Products LP-1002) so that it could be checked:  This antenna is set on a bearing of 87 degrees (true) and is not rotatable.
• Using an antenna analyzer, the beam was swept and the VSWR was found to be in line with the antenna's specifications over the 6-45 MHz frequency range.
• While not absolutely definitive, this result indicates a high probability that this antenna is working as it should.  Had any elements been "bad" or had there been a short/open in the open-wire line that feeds this antenna's elements, the results would have been much different.
• Because this antenna does seem to be OK, we have even fewer excuses for not using it - stay tuned!
  
• Radio/Internet link tweaked:  We have observed that the wireless Internet connection to the site has been having intermittent issues over the past several months.
• Having some time to check things out, we noticed that over two of the three wireless links that connect the site there were occasional packet loss/jitter issues that were traced down to the radio's "switching gears" (e.g. modulation) frequently.  While this is supposed to be "loss-less" (according to the manufacturer, at least) anyone who uses these radios knows that this isn't strictly true:  At the very least, this constant modulation change will cause queuing of data and increase jitter (not idea for streaming audio!) and in severe cases, packet loss.
• To "improve" performance, the radios' configuration was changed so that they would not attempt too-high a modulation method, staying at a lower, more stable rate.  This reconfiguration significantly improved one link and made a noticeable difference on another - which seems to have other issues which will have to be addressed.
• "40PH" and "80CW" receivers "un-swapped":  On a previous visit (see the 30 December, 2018 entry) the "80CW" and "40PH" receivers had been swapped because it was considered that with 40PH using a USB interface, it may have been less reliable than the sound card.  It was later noted that the sound card to which we had moved "40PH" had inferior out-of-band image rejection (e.g. less-effective low-pass filtering) than the original USB-based card (see 24 March entry) - so it was moved back to the original USB card.
• It was observed that despite several attempts at I-Q amplitude/phase balancing, the in-band image rejection on the "80CW" receiver is not as good as we'd like it to be:  This probably doesn't directly relate to the problem mentioned above - but it might.  Because this is a lesser-used band and because the image rejection is "OK" it was decided to leave this mystery for another day...
• Because there are now (lower performance) redundant receivers for 80/75 and 40 meters, if we experience a failure on either of these bands on WebSDR1 we are covered!
  
• Gain increased in the KiwiSDR "HF" signal branch:  About 9 dB of additional gain was added in the HF signal path that feeds the KiwiSDR stack (e.g. from about 400 kHz to 30 MHz) as an experiment to improve weak-signal performance.  A bit more improvement is still needed in the LF signal path (below about 400 kHz) but that will have to wait for a day with nicer weather.
• KiwiSDR fans relubricated:  It would appear that the cooling fans in the KiwiSDR's cases use somewhat inferior oil/lubricant - a common complaint with inexpensive Chinese-made fans whether they use sleeve or ball bearings.  The fans in all three Kiwis (which use sleeve bearings) were relubricated with a PTFE-based oil that is known to greatly improve the lifetime of these fans.
  

• 24 March, 2019.  Comments:
• Power line noise:  With recent high winds and heavy rain, insulators on the power lines near-ish the WebSDR site are again making some noise, most strongly in the 2.5 and 5 MHz area.  While this noise is occasionally audible on 160, 80, 60 and 40 meters during daylight hours, it is usually inaudible at night when these bands typically get noisier - particularly as the summer season approaches.  We continue to work with the local power company to minimize this issue.
• Update on RTL-SDR "gain block" (see 26 February entry):  Now that the AGC circuits for the RTL-SDR receivers for the 90-80, 60, 41-40 and 31-30 meter bands have been in use for about a month, I'm pleased to report that the results have been very good:
• These modules have been very successful in preventing overload from strong signals on those bands while allowing enough system gain for good weak-signal performance.
• It would appear that the 31-30 meter module needs a couple dB more signal gain during "quiet" periods when the bands are closed or in poor condition.
• The bandpass filters used for 90-80, 60 and 41-40 meters may be replaced with "tighter" versions (same bandwidth, stronger "skirts" to better-reject other signals) - just because I can, but this is not a high priority project.
• I may adjust the AGC threshold from the current setting of about 40% A/D full-scale - which seems to be working fine - to 25% full-scale so that I can observe the results to see if there are any improvements.
• As expected, there are some RMDR-like issues with weak signals on the RTL-SDR based receivers (e.g. weak signals "seem" slightly noisier than they should be, particularly if there are strong signals within the receiver's RF passband) but these are only apparent in an "A/B" comparison between an RTL-SDR receiver and one of the "High Performance" Softrock-based receivers:  The casual operator would likely not notice this.  This is, no doubt, largely a result of the limited bit depth of the RTL-SDR receivers.
  
• 6 Meter receiver:  So far, the 6 meter receiver is behaving itself after the 14 March reset.
• 40 meter images:  It was noted that some images have been appearing at the low end of the 40 PH receiver from strong signals above its coverage range.
• For example, an SWBC carrier can sometimes be heard at 7133 kHz from a signal at 7325 kHz:  7325 kHz is 8 kHz above the opt of the 40 PH receiver (which is at 7317 kHz) and this image is therefore 8 kHz above the bottom end of this receiver (at 7125 kHz).
• This defect is due to the lack of a perfect "brick wall" filter above the 96 kHz Nyquist frequency (with the 192 kHz sample rate) "wrapping around" and appearing at the bottom.
• This issues was not known to occur prior to the 30 December "hardware shuffle" where the sound card that had been used for 80CW was swapped with that used for 40PH.  It would appear that the "old" sound card was more resistant to this aliasing.
• We plan to "re-swap" the sound cards on the next site visit because of the larger overlap on 80 meters and the lack of very strong SWBC signals on 80/75 meters (as compared to 40 meters) which means that not only should this problem be less likely occur on 80CW, but the larger overlap allows user to "dodge" such aliasing should it occur.
• The actual suppression of this image appears to be on the order of just 12dB - increasing to 50dB by the time one gets to 136 kHz (which correlates to 7355 kHz) - which is much poorer than expected and why we plan to make this hardware swap.
  

• 14 March, 2019.  Comments:
• 6 meter receiver offline (WebSDR2 - Green):  It was noticed today that the 6 meter receiver is currently offline.  An attempt was made to restart the driver, but this attempt failed with errors indicating that something was amiss with the receiver hardware itself.
• A server restart will be attempted in the late evening when there is typically little use on the Green WebSDR (#2).
  
• This receiver uses an inexpensive ($20) RTL-SDR dongle, so replacing it won't be a big deal - except for the 3 hour round trip drive to do so!  It is likely that replacement will simply wait until the next trip to the site to do other work, which will likely not occur until early April at the soonest - unless something else breaks!
• Update - 6 meter receiver back online:
• After a restart of the WebSDR service failed to bring the 6 meter receiver back online, WebSDR2 (Green) was rebooted remotely:  This seems to have restored operation of the 6 meter receiver... for now...
  

• 27 February, 2019.  Comments:
• Added "Mode" indicator:  Something that had been bugging me from the time we put the WebSDR online was the fact that may not have been obvious what "mode" (LSB, USB, CW, FM, AM) had been selected:  The only way to "see" this was to take a close look at the size and position of the shape of the filter on the waterfall display - or one could simply click on a mode button to know for sure.  I finally got around to adding a "Mode" indicator which can be seen just to the right of the frequency display - where it belongs.
• Analysis of the RTL-SDR "gain block":  Initial indications are that the AGC gain block for the 90-80M, 60M, 41-40M and 30M RTL-SDR based receivers are working exactly as expected.  As we move into summer we'll see how it behaves in the presence of lightning static.
  

• 26 February, 2019.  Comments:
• Kiwis offline:  A site visit was made, noting that the KiwiSDRs had been offline for about a day, apparently due to crowbarring of the power supply.  On the next visit modifications will be made to the supply that will (hopefully) make it more resistant to this.
• Maximum number of users increased:  For WebSDR1  (the "Yellow" one) the maximum number of allowed users has been increased from 90 to 125.  This should (for the time being)alleviate the denials of service that one might have been getting during very heavy usage periods.  In the next "month or two" the Internet connection to the WebSDR system will be changed to one that is (hopefully) more robust and further increases in the number of users can be accommodated.
  
• Oops:  A previous modification - replacing an amplifier in the early stages of the broadband branch- was undone.  It had been noticed that this amplifier (a MMIC type), which had been replaced to provide a bit more gain and lower system noise figure (again, for the broadband branch) was causing low-level intermod and the problem was assumed to be overdriving of the subsequent stage.  When a gain adjust was added after this "new" amplifier the problem did not diminish and several weak spurious signals were seen drifting through the 0-30 MHz passband from this branch indicating that this amplifier was oscillating - likely at VHF/UHF - and was likely responsible for the problems.  Unfortunately, this could not be tamed with components on-hand so the previous known-stable bipolar amplifier was re-installed.
• "New" Bands - "90-80M" and "41-40M", improvements to 60 and 30 meters:  A newly designed and built module containing four bandpass filters, each followed by a wideband AGC gain block was installed in front of four RTL-SDR based receivers on 60 and 30 meter bands.  Two "new" bands were installed at this time on the "blue" server (WebSDR #3) - 90-80 Meters and 41-40 Meters.
• These cover all of the 80 and 40 meter bands, respectively, but also their adjacent SWBC bands, namely 41 and 90 meters.
• These "bands" provide a usable "back up" for the popular bands (80/75 and 40 meters):  In the event that WebSDR1 were to go offline and could not be restored remotely we would point users to WebSDR3 where it is likely that they could operate as normal.
• Being RTL-SDR based they are considered to be "low performance" receivers - but they should be "good enough" for casual use when signals are reasonably good.
• The AGC gain block in front of each of the respective RTL-SDRs is designed to prevent the RTL-SDRs from "seeing" signals that average more than about 1/2 full-scale on their A/D converters, which should prevent overload.  The use of this module also allows these dongles to be run a bit "hotter" than on normally would, improving their performance when the bands are "quiet" with the AGC preventing overload when very strong signals (mostly shortwave broadcast) are present.  These modules will be described in more detail, soon.
• The 60 meter receiver also runs through an AGC gain block allowing its sensitivity to be increased while preventing it from being overloaded by strong SWBC stations.
• The 30 meter receiver has a newer, "tighter" filter to improve its performance and it also has an AGC gain block like the 60 meter receiver which should also improve both weak and strong signal handling properties.
  

• 21 February, 2019.  Comments:
• A modification was made to the code on all of the Northern Utah WebSDR servers so that the default amount of audio buffering is now 0.25 seconds rather than the original 0.125 seconds buffering.  This slight increase (by 1/8^th of a second) is likely more appropriate for real-world Internet connections and should reduce the number of audio drop-outs.  If desired, the original value may be selected from the "Audio Buffering" drop-down menu.
• The most common cause of audio drop-outs is the changing of the "focus" of the operating system away from the browser window with the WebSDR.  For example, if you switch the browser to a different tab, switch to a different program or even minimize a browser window your computer will dedicated fewer system resources to processing the WebSDR audio.  Slower computers are more prone to audio dropouts in this case.  Increasing the buffer may help this situation, but it is often a matter of the computer not processing the data from the WebSDR often enough in its round-robin servicing of the running applications to keep the system's audio buffer full.
• Another cause of drop-outs is the heavy use of ones Internet connection - perhaps due to watching videos from online services (e.g. Netflix, Amazon, Hulu, YouTube, etc.).  In this case, more buffering will likely reduce the likelihood of drop-outs.
  

• 11 February, 2019.   KiwiSDRs offline.
• It would seem that all three KiwiSDR units on site went offline at about 1702 MST on 10 February (0002, 11 February UTC).
• When this was investigated on 11 February (at approx. 1125 MST) it was noticed that both halves of the redundant 5 volt linear power supply had "crowbarred" - that is, its overvoltage protection had tripped.  Unplugging the power supply for 60 seconds to allow the capacitors to drain and plugging it back in restored operation.  The cause of this crowbarring is currently unknown:  Because these supplies are in "diode-ORed" redundant configuration, one of the power supplies could have tripped out earlier without being noticed.  We are considering means of remotely monitoring/resetting this and other power devices.

• 29 January, 2019.  Comments:
• Audio drop-out issues:
• There has, in recent days, been more data jitter on the Internet connection to the WebSDR site:  Our network guru is looking into this problem to see if there is a reason/fix for this.  An upgrade of this same equipment is pending warmer weather and the availability of time to do so.
• The control of the "additional audio buffering" has been enhanced to allow the connection to better-deal with "flaky" connections.  There is now a drop-down menu labeled Audio Buffering that has several options
• +0.125sec:  This uses about 1/8th of a second of audio buffering, which works out to approximately 1/4 to 1/2 second of total delay between the signal arriving at an antenna and you hearing it on your computer, assuming minimal latency of the Internet and your computer's processing.
• +0.25sec:  Another 1/4 second is added to the audio buffering.  This is currently the "default" setting for buffing on this WebSDR system.
  
• +0.5sec:  This adds another 1/2 second to the amount of audio buffering:  This amount of extra delay is generally tolerable if you are using the WebSDR as your primary receiver during a QSO.
• +1sec:  This adds a bit more buffering - one whole second more.  This amount of buffering may be a bit painful/awkward if you are participating in a round table or net.
• +2sec:  This adds two seconds more of audio buffering.  While this is fine for casual monitoring of signals, you probably don't want to set it like this if you are involved in a net or a round table!
• Important Note:  The waterfall and S meter are always near real-time and not affected by the change in buffering:  As more audio buffering as added, the waterfall and S-meter will increasingly seem to "lead" (e.g. be ahead of) the audio that you hear.
  
• Remember:  There are several possible causes of audio drop-outs in addition to issues that may be occurring at the WebSDR site:
• Your Internet connection may be a bit "jittery":  This is common for cable modem connection and Wireless Internet connection during "busy" times (e.g. evenings) when everyone is watching TV/movies online.
• You computer may be "busy":  If your computer is doing something in the background while you are running the WebSDR in a browser it may drop-out occasionally.  If the computer is "too" busy to process the data that it is getting, extra buffering may not help.
• You have minimized and/or put the WebSDR browser page in the background.  If you have switched to another task, the web browser won't be given as much processor priority and audio drop-outs can occur.  If the computer is "too" busy to process the data that it is getting, extra buffering may not help.
• Note:  As mentioned in a previous posting, additional gain installed in the broadband coupler (which feeds the KiwiSDRs, the SWBC, AM BCB and 60 meter receivers) has resulted in occasional intermod/spurious signals being audible on the above receivers - particularly a few "shortwave" sounds being audible in some places on the AM broadcast band.  This will be corrected on a future site visit when there is time to do a proper "gain balancing".

• 13 January, 2019.  Comments on work that was done on the WebSDR system on this day:
• All WebSDR servers:  Replaced the original dual-core 2.93 GHz processors with 3.0 GHz quad core processors.  This should allow more stations to use the WebSDRs and experience fewer audio drop-outs and faster response.  To be sure, the most common cause of audio drop-out is on the Internet connection between the server and the user and not due to the server itself as well as in user's computer - particularly when the web browser being used is operating in the "background" - especially when other programs are running.
• LF filters installed on Server power supplies:  It was observed that the power factor correction circuitry in the servers produced a strong signal in the 125-140 kHz range and it was hoped that this was the source of the noise that was clobbering the 2200M/1750M when using the E-field whip.  Unfortunately, that noise source was not (mainly, at least) from the power supplies, hence the installation of the H-field shielded loop mentioned below.
• 2200M/1750M antenna changed:  A low-noise shielded H-loop was installed for the 2200M/1750M receiver to help reduce the gaw-dawful noise that was present.  On installation the loop antenna was rotated to null the noise source that was found to be either to the north or the south.  What this means is that all signals originating from locations due north/south of the Northern Utah WebSDR site will fall into this null on any frequency below about 350 kHz - both on the "2200M/1750M" band on WebSDR3 and on the KiwiSDR receivers on site when tuning below 400 kHz.

• 7 January, 2019.  Comments:
• Maximum number of users increased to 90 on WebSDR1:  It was observed that the number of users on WebSDR1 would occasionally hit the (then) maximum user count (75) prompting an increase on that server - a change that required a restart of WebSDR1, which occurred at about 0630, 7 January, 2018, UTC.
• The current settings for the maximum number of users are:
• WebSDR1 (yellow):  90 users.  WebSDR1 is, by far, the busiest of the servers as it hosts both the 40 and 75 meter phone bands which are the mostly heavily used for nets and ragchewing.
• WebSDR2 (green):  75 users (no change)
• WebSDR3 (blue):  60 users (no change)

• 30 December, 2018.  Comments on work that was done on the WebSDR system on this day:
• Partial failure of  sound card:  A (previously-planned) site visit was made on this day and it was discovered that the USB interface of the sound card used for the "160M" band had degraded, unable to connect at USB 2.0.  For whatever reason, this malfunction rippled throughout all USB interfaces and similarly affected the two other USB sound devices.  The offending device was swapped out and all devices are now working properly.  (Note:  USB-based sound devices are used in addition to PCI/E devices because of the limited number of plug-in slots in the servers.)
• Hardware shuffle:  Because the "40ph" band is one of the mostly heavily-used it was decided to swap the "80cw" sound card (a PCI interface card) and the "40ph" in an effort to obtain greater reliability.  One slight down-side is that the card being used on 40ph has a more apparent "hole" at the center of its coverage (at 7221 kHz) as a result of a slight roll-off in amplitude at low audio frequencies of the sound card/receiver combination.  In practice this "hole" causes only a slight effect in the audio response of SSB signals that are atop it.
• Installation of a 2200-1750 meter receiver:  The antenna was connected to the 2200/1750 meter receiver on WebSDR3.  Unfortunately there is some AC mains related noise (possibly a switching power supply) that seems to be parked in its coverage range that can degrade its overall sensitivity.  The cause (and remedy) of this will be investigated on a later visit.
• Despite the noise source, this receiver seems to perform reasonably well in the upper portion of the "LowFer" band to the top of its range (180+ kHz).
• The KiwiSDRs, which are also coupled to this new antenna below 350-400 kHz, seem to be doing reasonably well with WSPR reception on the 2200 meter band - probably because the required bandwidth for WSPR operation is very small and it manages to evade some of the noise components.
  
• Improved receive performance below 350 kHz:  Below approx. 350 kHz added filtering/amplification in the receive chain and a new LF/MF antenna combine to provide 2200M coverage on WebSDR3 as well as on the KiwiSDRs.
• Lower noise amplification installed:  Lower-noise amplification (based on the Mini-Circuits Gali74+ MMIC) was installed on the "high" branch of the main filter network provide some additional gain and a 3-4dB lower noise figure on bands 20 meters and up:  This also improves performance of the 17 and 12 meter receivers in particular as their hardware (each, a SoftRock Ensemble II) is slightly "deaf".
• A similar amplifier was installed for the 160 meter receiver to make up a slight gain deficit of that particular hardware (also SoftRock Ensemble II) as well.
• Finally, yet another lower-noise/higher gain module was installed in the broadband coupler (which feeds the KiwiSDRs, the SWBC, AM BCB and 60 meter receivers).
• Comment:  The levels for this change in gain have not yet be properly "balanced" resulting in occasional intermod/spurious signals being audible on the above receivers - particularly a few "shortwave" sounds being audible in some places on the AM broadcast band.  This will be corrected on a future site visit.
  
• Additional RFI suppression on cables:  Some snap-on ferrite filtering was installed on cables entering/exiting the building (network, RF) and a visible reduction of "computer" and power supply noise on 2 and 6 meters was noted.
• I/Q rebalance:  A thorough I/Q rebalance was performed on the 80cw, 40cw and 40ph receivers:  A rebalance for 80cw and 40ph was required because of a change in the hardware used for those bands.  On future visits, other bands will be rebalanced to minimize image response.
  

• 27-28 December, 2018.  Comments:
• Problems on WebSDR1:  Seemingly because no good deed goes unpunished, a known bug related to USB hardware reared its head:  Several of the USB ports - starting with the 160 meter receiver's sound card - suddenly "downgraded" their connection from USB2.0 to USB1.1.
• The upshot of this is that the 160m, 40cw and 40ph bands - all of which use USB-connected sound cards (Asus Xonar U5 and U7) - could no longer support a sample rate greater than 48ksps - a far cry from the needed 192ksps.
• Originally, it was just the 160 meter band that had this problem so a reboot was performed remotely - but the problem spread to the other two sound cards that provide 40 meters, also USB devices..
• In researching this problem it became clear that any means of completely resetting the USB hardware via command-line was unknown - but the work-around was simple:  Completely remove the power from the computer for a short time to allow the hardware to reset.  (Note:  Even when the computer is "off", the USB hardware may still be powered up.)  This was tried, but the problem didn't resolve:  There may have been some sort of  subtle hardware failure, or it may be required to keep the unit powered down for a much longer time than was tried.
• As a temporary work-around, the 40ph and 80cw receivers' connections have been swapped to restore full 40 meter phone coverage, albeit at the expense of some 80 meter cw coverage:  Because 40ph is the more-popular band, we believe the trade-off to be worth-while.
• The errant hardware (160M, 80cw and 40cw after the above shuffle) has been reconfigured for 48ksps, but this dramatically reduces the frequency coverage on those bands/segments, but it's better than nothing!
• Please note that while only partial 160M coverage is available on the "high performance" receiver, the "AM-160M-120M" receiver should work fine for most 160 meter use.
• At the next site visit (scheduled for 30 December) we will investigate this problem and try to determine a "permanent" fix.
  

• 26 December, 2018.  Comments on work that was done on the WebSDR system on this day:
• Intermittent outages:  Some portions of the system were brought on/off line to facilitate work on the WebSDR hardware.
• System outage:  All WebSDRs on site were down for about 90 minutes due to a localized power failure while we were working on-site.
• Addition of a 2200/1750 meter receiver:  A new receiver was added to WebSDR3 (blue) to provide coverage of the 2200 Meter amateur band and the 1750 Meter experimenter's band.  Unfortunately, the coaxial cable for the antenna was not available at the time so the outside antenna was mounted and hardware tested with a signal generator.  The coax from the antenna will be run in the next several days, in the meantime there will be no signals audible on this receiver.
• Another KiwiSDR added:  A third KiwiSDR receiver has been installed and added to the "pool" of KiwiSDRs.  One should connect only to KiwiSDR1:  If all of its receiver "slots" are used up, you will be forwarded to the next available slot on #2 or #3.  Please refrain from using the KiwiSDRs for frequencies/bands that are already covered by the main WebSDR system!
• Low LF/MF signals levels on the KiwiSDRs:  The signal levels below 530 kHz on the KiwiSDRs are lower than they should be - but this will be corrected during the next site visit.  The reason for this is two-fold:
• An LF/MF diplexer was added to the signal path:  Frequencies above approx. 350 kHz will come from the main HF antenna (the TCI-530) and those below 350 kHz will come from a newly-installed E-field whip.  Because the whip is not connected at this time, signals below about 350 kHz are cut off.
• The addition of the diplexer/combiner network caused a 3-6dB loss at LF/MF frequencies, putting the (already marginally-low) signals at these frequencies below the A/D threshold of the KiwiSDR.  A "gain realignment" will be done on the next visit to bring the signals back up to proper levels.
• Another visit to the WebSDR site is tentatively scheduled for  Sunday, 30 December, 2018.
  

• 16 December, 2018.  Comments:
• Powerline noise:  The powerline noise has been quiet recently (knock on wood) and it is not known if this can be attributed to repairs by the utility, or because of the season and recent "washing" of the lines' hardware by rain and snow.  Let us hope that it never returns!
• Comment:  Some powerline noise appeared again two days after originally posting this - go figure...
  
• Modification of S-meter "peak" reading:
• A "bug" has been fixed that prevented the "peak" value display below the S-meter from actually reflecting the peak value.
• Additionally, the peak reading now has a "hang" to it like a real-life S-meter in that it will (somewhat) drop from the peak (with a timed-exponential decay rate) instead of the previous, "chunky" updating.  What this means is that the peak signal level will persist for a fraction of a second and then drop, increasingly quickly, until it senses a new peak either from an existing signal or when it hits the noise floor.  This has no effect on the receiver AGC.
• The "Signal Strength" plot feature now has two more items in its drop-down menu:  Both a "fast" and "slow" version that uses the peak value instead of the instantaneous value.  Because the "peak" value is a "peak-an-hold with decay", signal plots of signals that vary considerably in strength (e.g. SSB) will be reduced from a scattering of dots to more coherent lines.  Because the "peak" value of the S-meter has an exponential curve, you will see this downward curve in the signal level

• 24 September, 2018.  Comments:
• Modification of "Bandwidth" menu:  The "wider" and "narrower" buttons that had been to the right of the mode selection (USB, LSB, AM, etc.) have been removed as they were redundant:  These same settings and more were already available under "Passband Tuning" just below the mode selection.  The removal of these buttons makes the box slightly narrower and may help improve layout/presentation at some screen resolutions.
• Powerline noise:  A long-running issue has been powerline noise.  Some of the culprit poles have been identified, but it is entirely up to the power company to decide when something might be done about them.  At present the worst powerline noise is centered in the general area around 2.5 MHz - outside any amateur bands - but it can affect the low bands (160, 80, 60 and 40) during daylight hours when these bands are typically very quiet.
  

• 21 September, 2018.  Comments:
• Sedona, AZ WebSDR shut down:  After about 6 years of operation, Steve, W7RNA has shut down the Sedona WebSDR.  Steve, W7RNA says, "...I have taken down the WebSDR at Sedona. Except for daytime regional coverage in Arizona and New Mexico, KFS and Utah WebSDRs cover the West so very well now, that I thought this was a good time to turn off Sedona as being effectively redundant.   The existing W7RNA links now forward to the two year old Kiwi SDR at the same location. As you probably know, the Kiwi is limited but it can still serve Arizona and New Mexico for the few users that still may need it during the day on 40 and 80m."
• We would like to thank Steve for having provided this valuable service and those of us at the Northern Utah WebSDR have been the grateful recipient of his technical advice and expertise.
• "AM-160M-120M" band coverage shifted:  The center of this band was shifted slightly so that it's center frequency (which is also the default frequency) lands squarely atop an even 10 kHz interval rather than several kHz off, barraging the user with distorted music.  At present there's no way to select a default frequency other than shifting the entire receiver's passband and this limits our selection if we wish to be able to receive over this frequency range.
  
• Intermittent network slow-downs:  Our rather long-length wireless Internet connections are sometimes showing down connectivity - but these "slowdown" periods seem to last only an hour or so.  We're doing what we can to figure out a way around this.

• 10 September, 2018.  Comments:
• Network Outage:  On the evening of September 9 (local time) the combination of bad weather, a bird's nest and faulty insulators on the power line that feeds one of the microwave sites that provides Internet connectivity to the Northern Utah WebSDR disrupted operations when that site lost power for several hours.  While the back-up battery at that site held for a time, the duration of the outage exceeded its capability while the local utility crews worked late into the night to replace the failed hardware.  The duration of the network outage was approximately 3 hours and 45 minutes.
• Expansion of WSPR decoding capabilities:  On 8 September reconfigurations made it possible for up to 12 simultaneous "bands" to be used for receiving and decoding HF WSPR transmissions but only 8 or 9 channels will typically be used at one time.  This is done by using an on-site computer (WebSDR3, actually) to make local network connections to the on-site KiwiSDR receivers and pull audio from them from virtual receivers tuned to the WSPR frequencies (these show up as a user called "kiwirecorder.py") which are saved as files and then processed to recover the WSPR transmissions.  As a reminder, the KiwiSDR receivers can each take up to 8 users, but only the first two users on each will get a full-bandwidth waterfall display:  These recording channels do not use any of the waterfall capabilities.  The results of this effort may be seen at the wsprnet.org site with the contributor being "KA7OEI-1".  It is hoped that future efforts will enable things like contributions to the RBN (Reverse Beacon Net) and similar.
  

• 17 September, 2018.  Comments:
• Over the past several months we've been having issues with the wireless Internet connection to the WebSDR spontaneously "re-training", causing an outage of between 30 seconds and 5 minutes.  The reason for this seemed to be something amiss with the firmware on the radio link between the WebSDR site and the next point on the network.  We think that this problem has been resolved after firmware/hardware updates.
• A different problem occurred a few weeks ago when one of the main wireless trunks, which had been been capable of passing up to 1 Gb/sec of traffic suddenly decided that it would only negotiate to 100Mbps.  During the "off" hours of the day this wasn't so much of a problem but since the peak traffic on the network could be over 350Mbps, dropped packets and audio issues could result.  This "bottleneck" has been fixed as of about a week or so ago:  We were just watching it to see if it was really fixed before updating this and the main WebSDR pages.
• Ongoing issues:
• Powerline noise:  We have identified the suspect poles and passed the information to the power company.  All we can say is:  "They will fix it when they do."
• The "warbly":  As noted  in the 30 June, 2018 entry and the 9 June and 16 May entries there is a "warbly" that often shows up when the band is very quiet (e.g. 40 meters during the daytime) - one of its harmonics seeming to frequent the area near 7272 kHz, where the Utah Beehive Net meets.  This is still on our list to address, but again, it will take climbing to about 60 feet on a tower and pulling up excess service cable in order to add the ferrite devices that (we think) should quiet a POE (Power Over Ethernet) device mounted there.
• Occasional "crackle-crackle" on received signals - particularly the lower bands:  As noted earlier, one of the guy wires on the antenna will occasionally touch an active antenna element when it is very windy.  We are trying to figure out how to access and insulate these two conductors - but their being at about 80 feet (24 meters) up the tower doesn't make it easy!
• A few instances of low-level QRM from miscellaneous switching power supplies:  While not easily noticed (unless you knew exactly where to look) there are a few "birdies" from other switching power supplies on site - typically on the lowest band (e.g. 160 meters and below.)
• Intermodulation on some lower bands (<=80/75 meters) during the daytime:  During daylight hours one may notice a few instances of intermodulation distortion on some of the lower-frequency bands, particularly below 2 MHz.  Much of this energy appears to be re-radiated from rusty barbed-wire range fencing surrounding the receive site but it's possible that at least some of it may be happening in the receive antenna itself and even some of the RF distribution.  Practically speaking, this hasn't been much of a priority to fix because:
• The majority of the strong signals (several of them 50kW stations) are reduced in power at night in accordance to conditions of operation imposed by the FCC to minimize their interfering with other stations.
• At night, these bands (80/75, 160, 630, etc.) become more "alive" and compared to the daytime, the background noise actually increases, drowning out the intermodulation products that might otherwise be audible even after the stations reduce their power at night.
  

• 9 September, 2018.   More problems with the Chrome browser!
• It would appear that a very recent update to the Chrome web browser (such as 69.0.3497.81) has caused yet another audio problem:  Sudden, loud crashes of noise - or one may hear only white noise, particularly when first starting the web page.
• While muting/un-muting on the WebSDR itself may correct this, the effect will probably be temporary.  
• There's no known work-around yet so it's recommended that you use a different browser:  Firefox works well and is recommended!

• 12 August, 2018.  Comments:
• A Second KiwiSDR was installed at the site and some minor networking issues were resolved allowing both of the Kiwis to show up on the main list at the sdr.hu (link) site.  The URL for the first (main) unit is kiwisdr1.utahsdr.org.  For more information, read the KiwiSDR section of the FAQ.
• Please read and understand the following:
  
• If you are doing casual listening on the amateur bands, PLEASE use the main WebSDRs instead!  The reason for this is that the main WebSDRs can handle dozens of users at once, but the KiwiSDRs can handle, at most, only 8-10 users.  Most of the receivers on the main WebSDRs are better performance than the Kiwi, anyway.
• These receivers are configured to allow "roll-over" so that if all of the receiver channels on the first (main) one are occupied, it will forward to the second.
• Each of these receivers is configured in the "8 channel" mode which means that only the first two receiver instances will have a full-bandwidth waterfall.  At some point in the near future the "other" receivers may get a more limited waterfall.
• Each of these receivers have several channels dedicated for WSPR use and are not available for general use showing up on the WSPRNET web site as "ka7oei-1" and "ka7oei-2" for units 1 and 2, respectively:  These WSPR-only "receivers" do not utilize any of the limited waterfall capabilities.  Clicking on the Kiwi's USERS tab will show the current status.  
• At this moment, casual users are only allowed 90 minutes total use during any 24 hour period:  Abuse or lack of it will dictate the need for any adjustments either way.
• Both KiwiSDRs use the same omnidirectional antenna as the main WebSDR system so receiver performance should be pretty much identical to other receivers covering comparable frequencies.
• The KiwiSDRs do not work with Internet Explorer (and never will) and do not count on them working properly with mobile devices!
• There are a number of "extensions" that allow reception/analysis of various types of signals, including RTTY, FAX and WSPR.  There is also a "TDOA" feature that can help one determine the geographical location of a particular signal - but there is a bit of a "learning curve" in using it - I would strongly recommend reading EVERYTHING in the "help" tab that appears - and the linked page(s) - when you invoke the TDOA mode.  Remember:  RTFM! (such as it is..)
• The features and configuration of the KiwiSDR receivers WILL CHANGE over time as software evolves and as circumstances warrant.
• Enjoy!

• 8 August, 2018.  Comments:
• An outage of approximately  60 minutes duration occurred due to power loss at one of the wireless Internet link(s).
• The "idle" time of the WebSDRs (e.g. you, the user not interacting) has been increased from 60 minutes to 90 minutes for WebSDR #1 (yellow) and WebSDR #2 (green) and 120 minutes for WebSDR #3 (blue).

• 7 July, 2018.  Comments:
• Those who use the WebSDR on 80/40 meters during the day will likely have noticed an elevated powerline noise floor:  At night, this noise is submerged in the normal background noise of these bands.  Being that the WebSDR site is an 80 mile (130km) drive for me each way, I understandably try to limit the number of trips that I have to take - particularly since it involves nearly three hours driving and (at current prices) $30-$40 of gas for each round trip!
• On this day I went to the WebSDR site and carrying a 2 meter AM/FM direction-finding receiver (a VK3YNG unit), a 3 element tape-measure beam, my FT-817, a battery, a 3 foot (1 meter) diameter shielded H loop, a homebrew ultrasonic down-converter and a small plastic parabolic dish with an ultrasonic transducer, I tromped through chest-high (5 feet/1.5 meter) swamp grass in 102° F (39C) heat, following about 2 miles (3.2km) of powerlines looking for noise sources.  With this effort, three power poles were found with very strong, vertically-polarized noise (at VHF) and one of these had just-detectable arcing noise at ultrasonic.  I also found a "corner" power pole on this 38kV line on which one if its deadmen (guy wire anchor in the ground) had completely pulled out in the direction of the greatest force.  Taking pictures of the suspect poles, these will be reported to the power company:  Particularly in light of the failed anchor, we are hoping that they will do what they do to quash this type of noise.
• The 25 and 19 meter bands' filters were analyzed in-situ and it has been determined that over the 25 meter SWBC band, the image response (centered at approximately 16.8 MHz) is attenuated by approximately 26dB while the image response in the 19 meter SWBC band (centered at approximately 13.55 MHz)  is attenuated by approximately 22dB.  Because of its proximity to the 14.4 MHz Nyquist frequency of the RTL-SDR dongle and the finite "sharpness" of the band-pass filters, the image rejection at the 14.67 MHz CHU (Canadian time station) is only about 8dB at the 14.13 MHz image frequency.  While these values are certainly mediocre, they are adequate for casual listening on these bands and far better than many inexpensive "all band" shortwave receivers of the past.  I may, in the future, modify/replace these filters with "sharper" versions with stronger image frequency attenuation.
• It might be noticed that some of the 25 meter SWBC band images fall in the 22 meter SWBC band centered at approximately 13.75 MHz, which correlates to 15.08 MHz.  What this means is that some of the stronger 22 meter SWBC signals are likely to appear in the lower portion of the 25 meter receiver's passband.
  

• 3 July, 2018.  Comments:
• Michael was able to drop by the WebSDR site (he lives in the general area) and adjustments were made to the 25 and 19 meter SWBC band receivers - namely the gain block before the filtering was moved to the output of the 19 meter filter and the signal path attenuation was adjusted for both bands.  Initial indications are that, at least for moderate/good band conditions, the receivers should overload less often.
• In addition, the 19 meter receiver was configured for 1.5 MHz bandwidth and it now includes 14670 kHz - the frequency of the Canadian time station, CHU.  Please note that especially below 15 MHz, this receiver is prone to images from below and in the 20 meter amateur band - the inevitable result of the Nyquist frequency of the RTL-SDR dongle used occurring at 14400 kHz!

The new deadman anchors with the tower in the background and the guys being tensioned.
Click on the image for a larger version.

• 30 June, 2018.  Comments:
• New UPS installed:  As noted in the 12 June entry, the 500VA UPS failed unexpectedly (what other kind of random failure is there?) and a "new" 700VA UPS was installed - not as nice as the "old" one, but it should serve its purpose.  At this same time a simple transfer switch (a mains-powered DPDT relay in an electrical box) was installed that allows us to change in/out other UPSs in the future - and it will automatically switch the mains power, should the new UPS fail, from the "A" source (the UPS) to the "B" source (the wall socket).
• The 25 and 19 meter shortwave broadcast bands (SWBC) were installed:  On WebSDR 3 (the "blue" server) some RTL-SDR dongles with filtering were installed to provide coverage of these two shortwave bands.  While the levels were adjusted appropriately at the instant that we installed them, it is clear that we missed the mark and that the receivers sometimes overload very badly resulting, at times, in a cacophony if noise, overlapping audio signals and distortion..  
• Please consider the operation of the 25 and 19 meter receivers to be a work in process!  As noted on the "Technical Info" page, these RTL-SDRs, with there limited dynamic range, required a certain amount of finesse to adjust properly to accommodate the majority of weak and strong signal conditions.  These levels cannot be adjusted remotely so they will be "dialed in" on future visits.
• The 6 meter band (the bottom 1 MHz, anyway) has been moved to WebSDR2 (the "green" server):  It would appear that the WebSDR software (or, possibly, our server hardware) will only "play nice" with a maximum of 4 RTL-SDR devices.  When we added the 25 and 19 meter bands to WebSDR3 (blue) the last receiver ("2M High") would not initialize.  For this reason we used the last remaining band slot on WebSDR2.  It is configured identically to what it had been when it was on WebSDR3.
• One of the power line noise sources (possibly) located:  We think that we found a power pole that is one of the sources of AC mains noise that becomes apparent when the lower bands (80/75/40) are at their quietest (e.g. daytime).  When we approached the pole in question it was noted to have a damaged insulator on one of the phases:  We will report this to the power company.  It is very likely that this is not the only nearby power line noise source, but we have to start somewhere!
• Internal gain blocks added to the 15 and 10 meter converters.  When the 10 meter converter was installed on 9 June it was noted that it was "gain-starved", so a general-purpose external gain block (high-dynamic range amplifier) was installed between it at the RTL-SDR dongle.   A similar issue was noted on the 15 meter converter so an additional gain block was internally added to both the 15 and 10 meter converters and the levels readjusted for best performance.  This additional gain should help when the band is very "quiet", bringing the signals comfortably above the receivers' noise floors.
• The "warbly":  We did not get time to further-address the "warbly" mentioned in the 9 June and 16 May entries.  To further reduce this noise will require pulling additional Ethernet cable up the tower (the "other" tower, not the one supporting the antenna that we are using at present) to get enough "service loop" to be able to add enough inductance to the cable to choke the common-mode energy.  This warbly is audible only during daylight hours when the band is quiet and line noise is very low.

• 20 June, 2018.  Comments:
• Nearly 2 months ago the north deadman of the "other" tower (not the one supporting the receive antenna) pulled completely out of the ground during high winds - the worst of which usually come from the north at this location.  In a stop-gap measure, one of the locals kindly parked his large, flat-bed farm truck and attached the the guy wires to it until he got room in his schedule to come back and replace the deadman - which occurred on this day.
• Rather than excavating a hole and setting the new deadman in concrete, long, thick-walled steel pipes were pounded deep into the ground with a pile driver, the first one (to which the wires were attached) being belayed by another behind it, connected by a piece of heavy pipe.  This method - used to tension many thousands of feet of fencing - has been used for decades with good results.  In the near future, the other two deadmen will be similarly replaced although they appear to be sound... for now...
• The "front" pole has, below ground, a large "spade" attached to it to increase its stability and "pull strength" in the soil.
• While we won't mention up front how much this is costing us, it's safe to say that it wasn't cheap!  It should, however, prevent this tower from suffering the same fate as its twin which failed in the very same way about a decade ago.
• Now that we have better-stabilized this tower, we are looking into what can be done with the antenna which at 80 feet (24 meters), covers from 6 to 40 MHz and is fixed (there is no rotator) on an 86° (true) bearing - just slightly north of due east:  We have not yet climbed the tower with an antenna analyzer to determine its usability.

• 18 June, 2018.  Comments:
• Power line noise finding postponed:  For various reasons, the "noise finding" trip that had been tentatively scheduled for 16 June never happened.  The noise persists, so we still have a trip planned to hunt it down - but it will have to wait until after ARRL Field Day (22-23 June, 2018) as we have previous commitments.
• Installation of the new UPS postponed:  This was going to be installed on the same trip as above.
  
• Slight gain deficit on 15 meters:  It would appear that there is a slight gain deficit on the 15 meter band.  While it seems to be adequately sensitive to weak signals, somewhat better performance could be had with another 6-10dB of signal gain.  This band is served with an RTL-SDR dongle and a frequency down-converter (as described on the RX Equipment page) and as noted, the RTL-SDR units are both somewhat deaf and quite particular when it comes to the amount of gain in the signal path.  On the next trip additional amplification will be put inline.
  

• 12 June, 2018.  Comments:
• 4 hour power outage.  The WebSDR servers and network gear were off for about 4 hours due to the failure of the on-site UPS.  While there was no actual power failure, the CPU within the UPS seems to have lost the ability to measure its own output voltage and it shuts off its output soon after booting up: After power-cycling the UPS, it will operate properly for several seconds before it shuts the inverter down due to "Low AC Output Voltage" as determined by the alarm code and the remote status reading.  A "new" UPS is being lined up and will probably be replaced on 16 June.  In the meantime, the UPS has been bypassed with the gear running directly from the mains.
• Power line noise.  During the quietest parts of the day (late morning through the afternoon) there is noticeable AC mains noise on all bands 80 through 15 meters - most obvious if one listens using AM on 40 meters.  The plans are to investigate this noise on 16 June and hopefully locate its source and pass along that information to the power company.  As it turns out, some of the folks that service this area are also amateur radio operators, so it may be more likely to be fixed .

• 9 June, 2018.  Comments:
• With the addition of 12 meters, this WebSDR system now has coverage on all U.S. MF and HF amateur bands - 630 through 10 meters.:
• Full coverage of the 10 meter band.  A downconverter was constructed and with an RTL-SDR dongle, then entire 10 meter band is now covered.  Because the top is set at 29.7 MHz, coverage extends several hundred kHz below 28.0 MHz as well.
• 12 meter band coverage.  The receiver formerly used for the limited 10 meter beacon band coverage was retuned and is now centered on the 12 meter amateur band, covering about 96kHz of this 100 kHz band.
• The only HF bands that aren't completely covered are:
• 160M:  Even though the "main" receiver misses the top 8-10 kHz, the entire band is also covered using the "AM-160M-120M" receiver.
• 17M:  Approx. 96% of the band - missing the bottom and top 2-3 kHz.
• 12M:  Approx. 96% of the band - missing the bottom and top 2-3 kHz.
• For a complete description of the band coverage, see the "Technical Info" page.
• We have (finally) added a "Donate" button.  If you wish to help support the WebSDR, go here to find out how you may donate via PayPal.
• The signal strength of the "warbly" has been reduced.  The "warbly" (see the 16 MHz comments) was verified to be coming from a switching supply within a piece of wireless gear being radiated on the Ethernet cable.  Despite there not being a service loop, four snap-on ferrite chokes were placed over the cable, at the source, noticeably reducing its amplitude.  Unfortunately, without a larger service loop, it was not possible to put multiple turns of the cable through the ferrite devices which would have had far greater effectiveness at the frequencies of interest:  This problem will be revisited later.
• The 6 meter antenna was remounted.  Up to this point the 6 meter antenna (a 1/2 wave J-pole) was only temporarily mounted.  On the new, permanent mount, the antenna is now much higher and completely in the clear so it should work better than before.
• The main HF antenna feed connection was "exercised" and better-sealed.  Just outside the building, the large coaxial cable from the main antenna (the TCI-530) is adapted to a smaller cable (RG-213) for entry into the building.  During the 21 March visit (see below) this connection was "shaken" to resolve an intermittent RF issue and during this trip (e.g. 9 June) the entire connection was un-taped and inspected and found to be in good shape,  The connections were further-tightened and the entire termination was re-sealed using butyl rubber material and overtopped with another layer of sealing tape.
• Ongoing power line noise issues:  There is a more-frequent low-level power line noise that can be heard during the "quiet" times (e.g. during the middle of the day) on the lower bands - notably on 80/75 and 40 meters:  We are rounding up the necessary gear to do HF direction-finding to locate the source(s) of this noise so that we can report the location(s) to the power company.

Work being done on the power substation near the WebSDR site on 15 May.
Yes, those are bugs in the lights... Lots and lots of bugs.
Click on the image for a larger version.

• 16 May, 2018.  Comments:
• Power loss at the WebSDR site due to utility work on 15 May.  The power to the WebSDR site is fed via a spur of a power line that feeds a pumping/compressor station of a nearby pipeline, and on 15 May, a "50 year" upgrade was done requiring that this power infrastructure be de-energized, which meant that the WebSDR site lost power.  Being a minor customer on this same spur line, we didn't get notification of this work until the power had already been shut off.  Because of certain complications (e.g. most of us work for a living!) we were not able break free from our normal tasks and get a portable generator up and running on-site immediately, so the system was down for 7 hours or so.  The WebSDR site was on generator power until after the work on the substation was completed and the line re-energized.
• Data drop-outs of 5-120 seconds.  It would appear that one of the radio links providing Internet connectivity to the WebSDR site is occasionally "renegotiating" its wireless connection, causing brief data drop-outs despite the fact that the signal level margins are very good.  An upgrade of the affecting link is scheduled.
• A weak "warbly" sometimes heard on 40 meters and other places.
• In early April, a piece of POE (Power Over Ethernet) interfaced-equipment with a fairly long cable run was installed.  Unfortunately, as is the case with almost any piece of equipment that has switching supplies, one of the (many!) harmonics (spaced at about 250-251 kHz) of this supply can occasionally be heard in the local receiver.
• Fortunately, this "warbly" is quite weak, audible during daylight hours when the bands are very quiet:  The normal background noise of the bands at night completely covers this.  This "warbly" is wont to haunt 40 meters and is often heard in the vicinity of 7272kHz, the "default" frequency of the "Yellow" WebSDR server and the frequency of the Utah Beehive Net, but it tends to drift around a bit with temperature.  This same "warbly" has also been observed (during the daytime) on 75/80 meters and on 20 meters.
• On the next site visit steps will be taken to mitigate the signal(s) radiated by this equipment and it is expected that this problem will be eliminated.

• 3 May, 2018.  Comments:
• More fun with the Chrome browser!
• The "Start Chrome audio" button has been added to the "Mobile" versions of the WebSDR for those using mobile (phone, tablet) devices and the Chrome browser.  It is believed that this works properly, but consider it to be experimental for now.  Depending on your phone's configuration, the WebSDR audio may stop when your device goes to sleep/screen blanks:  If this proves to be an issue, we'll look into adding code that will prevent this - but doing so will cause your battery to drain very quickly!  Remember also that the Firefox browser works well with the WebSDRs, so you may consider using it, instead.
• If you are using the "normal" web interface with the Chrome browser on your phone, you may have problems with audio stuttering/echoing, and this seems to be due to too little processor time being allocated to processing the audio:  It may correct itself after a few moments - but if it happens to you, it probably won't.  Disabling the waterfall (the "blind" button at the top-left corner, above the waterfall - you may need to select "one band" an "blind" again) seems to help.
• The "mobile" version of the WebSDR interface doesn't seem to have this problem - neither does the Firefox browser with either the "normal" or "mobile" version of the WebSDR interface.  (This problem has been noted on Samsung phones running Android and it may or may not occur on other phones.)
• For more information about this, go to the "Chrome Fix" web page.
• Links on the "Mobile" web interfaces to the other Northern Utah WebSDRs have been added.
• The "additional audio buffering" button has been added to the main WebSDR pages.  This increases the amount of the delay between the reception and your hearing of the audio, but it can make the use of the WebSDR more tolerant of Internet connections that are slow and/or subject to larger amounts of jitter (e.g. mobile hot-spot, satellite, lower-speed "broadband", heavily shared connections).  This button is present on the "mobile" versions (near the bottom) for the same reason.
• Remember:  Most audio drop-outs are due to other applications running on the computer/phone/tablet taking processor time and NOT because of network issues.  Having the WebSDR running on a minimized window and running other processor-intensive programs is a great way to make the audio choppy!

• 1 May, 2018.  The "31M-30M" band on the "Green" server was reconfigured, increasing the bandwidth to 1536 kHz to cover down to 8676 kHz.  This expanded frequency range includes some of the HF frequencies used for aeronautical communications on ocean routes and frequency tags for these frequencies (and those aero frequencies that happen to be covered on the "60M-49M" band on the "Yellow" server) have been added.

• 26 April, 2018.  Comments:
• A clock showing UTC was added to all servers in the (otherwise) blank space between the waterfall and the controls to minimize the overall web page size and to place it where it is easy to see.  This clock is based on the time setting of the user's computer and not that on the WebSDR, which may not be precise.  The code for this clock was "borrowed" from the KFS WebSDR.  On 30 April the display of local time and an advisory about the clock's being based on the user's computer was added.
• The firmware of the data link connecting the WebSDR site to the back haul has been updated to fix what the manufacturer called "stability problems".  We are hopeful that the link will be more reliable.

• 20 April, 2018.  Comments:
• Chrome users:
• If you use the Chrome web browser a recent update may require that the user "activate" sound/video on web sites that have this type of content by clicking a button to activate it - but this works only if those same web sites have modified their code to include this button.  While we (believe that we) have modified the Northern Utah WebSDRs to have this button, it may take some time before these changes appear on other WebSDRs.  For more information about this, go to the "Chrome Fix" web page.
• Earlier this week there were some very high winds throughout northern Utah.  Since then, power line noise at the WebSDR site - which is intermittent by nature - is occasionally worse than it had been before.  While we are working with the power company to find the source of this noise, it is largely up to us to locate it and report the location of the suspected hardware to the utility.  As you can imagine, we need to find time to do this - and then hope that the noise is occurring at that same moment so that we can find it.
• During 19 and 20 April, some network upgrades were being undertaken, causing some occasional outages.
• Coincident to that, one of the wireless links connecting the WebSDR to the Internet started losing its mind, losing/regaining its authorization and dropping a lot of packets and occasionally going down altogether.  Once there was time to address this issue, this link was reprogrammed from the ground up and it is hoped that it will behave itself!

• 19 April, 2018.  Comments:
• The "630M-AM-120M" band has been shifted up slightly, now covering only down to about 519 kHz.  This was done because there is now a dedicated 630 meter band receiver.
• The "60M-49M" band has been shifted up, now starting at about 4700 kHz and covering to just above 6700 kHz.  This was done because there are (probably) more signals of interest 6600-6700 kHz range than there were down around 4500 kHz - although I don't know offhand what those would be...
• We have enabled ads on the WebSDRs - trying to keep them as unobtrusive as possible - to help offset the "fixed" expenses related to operating a WebSDR, such as power and site rental.  One side-effect is that they may slightly delay the loading of the web page.  To read more about why we did this, go the "Why ads?" article.

• 17 April, 2018.  Comments:
• Bands on individual servers are now in order of lowest to highest frequency rather than by "high performance" receivers first and then increasing frequency.
• The S-meter/waterfall gain settings on 40 meters that had been adjusted to compensate for the effects of the high-pass filter have been restored to their original values.
• A/D converter gain values on the 630 meter receive system were adjusted to provide better overall signal range.
• Minor name changes of several bands for better consistency.

• 15 April, 2018.  Comments:
• Resolved issue:  The high-pass filter was rebuilt.  This is used to block low-frequency (<25 kHz) energy picked up by the antenna in the form of electrostatic coupling that was causing problems at low receive frequencies - being particularly noticeable on the AM broadcast band as mains-induced hum.  The original filter was found to have a broad, shallow "notch" at around 40 meters that had reduced signals by about an S-unit.
• Resolved issue:  One of the sources of an intermittent problem where intermodulation distortion from AM broadcast would appear and disappear is believed to have been solved.  This was probably due to a flaky solder connection in the "wideband" branch of the signal path where one or more of the notch filters used to reduce the signal level from strong, local stations would occasionally fail.
• Upgrade - 15 Meters:  The 15 meter amateur and the 13 meter shortwave broadcast bands have been added to the "Green" server.  This uses a relatively low-performance RTL-SDR dongle preceded with a custom-built, tightly-filtered frequency converter, but it was verified that just will hear the ionospheric noise floor when the band is closed.
• Upgrade - 2 meters:  A south-pointing, 5-element 2 Meter Yagi is now being used for 2 meter reception.  This Yagi points toward the Salt Lake City metro area where there is the greatest concentration of repeaters.
• Upgrade:  The "Blue" server has been added, providing a few additional bands.
• Change:  2 meter coverage has been moved to the new "Blue" server.
• Upgrade - 6 Meters:  The bottom 1 MHz of 6 meters has been added, covered on the "Blue" server in preparation for the upcoming sporadic-E season.  The antenna for this band is not yet properly mounted so it does not (yet) work very well.
• Upgrade - 630 Meters.  The 630 Meter amateur band has been added to the "Blue" server.  This receiver covers from about 389 to 484 kHz, allowing some NDB (Non-Directional Beacons) to be heard - particularly at night.  Like 160 meters, the 630 meter band is mostly a "winter" band owing to the crescendo of static that accompanies the summer season.  While this band is also covered on the "630M-AM-160M" band on the "Yellow" server, this receiver has much better performance.  Note that this band can, at times, be badly affected by the intermittent powerline noise and intermod/antenna issues that we are experiencing.

• 11 April, 2018.  Notice:  There are/will be some occasional outages over the next week or so as our ISP does some equipment upgrades.

• 7 April, 2018. There was an extended power failure in the general area of the WebSDR, caused by a pole fire, that resulted in an outage that lasted significantly longer than a UPS powering one of the microwave hops providing Internet connectivity could.  Whether or not this had anything to do with our intermittent power line noise remains to be seen.  This outage provided the opportunity to reconfigure the power system to mitigate the aforementioned power issues at the "next" site along the network.

• 5 April, 2018.  Comments:
• Upgrade:  The original wireless link antenna used to provide connectivity to the WebSDR site was upgraded from its original 12" (25cm) to a 24" (50cm) antenna, providing better link margin.  This resulted in a pair of outages that totaled 10-15 minutes in the morning between 1130 and 1145 MT.
• Upgrade:  There is a UPS/power supply issue at the "next" site along the network from the WebSDR and brief power bumps at this site will cause a 3-5 minute outage.  This will be fixed (which will, itself cause a 3-5 minute outage) in the next several weeks.
• While on site today it was observed that the known-marginal north deadman on the other antenna tower (a log-periodic beam) had pulled completely out of the ground, leaving the guy completely slack.  The already-in-process plan to replace these deadmen has been delayed due to equipment problems of the person we have engaged to repair this;  In the meantime, the north guy wire has been (temporarily!) attached to a large truck.  There is no visible evidence of antenna/tower damage.  All three deadmen will be replaced, but because the strongest winds are out of the north, this is the one that is the most critical.
• Under investigation:  There is an intermittent issue where there are spurious 160 and 80/75 meter signals - most notably on 1940, 3480, 3600, 3750, 3870, 3920 and 3960 kHz, many of these seeming to involve a mix between 1160 kHz and other stations.  For the most part these spurious signals disappear at night when some sources of the signals reduce power as well as the ionospheric noise on these bands increase.  The source of this problem is believed to be a problem with one of the filter elements designed to reduce the levels of the AM broadcast band signals.  When this is at its worst the "630M-AM-160M" receiver may be unusable due to overload.
• Resolved issue:  It was discovered that, somehow, the sound card used for the "10M BCN" had reconfigured itself, switching the receiver audio away from the active input.  This was fixed for good - I hope!

• 27 March, 2018.   Comments:
• Resolved issue:  It was discovered that the "10M BCN" receiver intended to cover (most of) the 10 meter "beacon" subband from 28.200-28.300 MHz was actually centered on 28.350.  This receiver was retuned to a center frequency of 28.245 MHz (this frequency chosen to include the NCXDF beacons at 28.200 MHz) and immediately several beacons - including the "K7EMX" beacon located about 70 miles (112km) in Salt Lake and another beacon in Texas (K5AB at 28.280 MHz) - were heard, indicating that the receiver is now working properly.
• Resolved issue:  It was noticed that the "= kHz" button doesn't work correctly when the CW mode is active.  The problem had to do with the fact that unlike any other mode where the indicated frequency is that of the carrier (or suppressed carrier on SSB) the indicated frequency when using a CW mode is that of the center of the passband - or 750 Hz.  Because of this offset, the "= kHz" button caused the frequency to jump, being rounded using that 750 Hz offset:  After this offset was taken into account in the code, this problem was fixed.

• 24 March, 2018.  Comments:
• Resolved issue:  A brief site visit by Mike for the installation of a high-pass module on the main antenna feed which got rid of the AC mains related "hum" on signals received on the AM broadcast band receiver.  This problem is believed to be related to the pick-up of AM mains electrostatic fields from the antenna causing modulation of the magnetic properties of an input RF transformer and/or the modulation of one of the signal amplifiers.  This module provides a DC path-to-ground for the antenna as well as two (moderate) levels of lightning protection via gas discharge tubes.
• Related issue:  It was noticed that a stray resonance in the added filter seems to have caused approximately 1 S-unit of reduction in signals on 40 meters - but there is little or no actual loss of system sensitivity owing designed-in signal margins.  The filter will be modified during the next site visit.
• Resolved issue:  Extra gain was added in the "10M BCN" receiver's signal path.  Although there are two low-power 10 meter beacons known to be active in the Salt Lake area, neither one can be heard on this receiver - but this is not unexpected as propagation would be only via ground wave (which is rather poor on 10 meters, anyway) and the distance is simply too great to hear them.

• 21 March, 2018.  Comments:
• Under investigation:  It was noted that the RF levels on all HF bands were shifting randomly over the day by as much as 12 dB.  A brief site visit was made by Mike who lives near the site and he shook the cables/connectors between the RF rack and the antenna - we may have found an intermittent RF connection on a jumper cable:  This will be investigated further on the next "full" site visit.
• The 10M BCN band was added at the time of this visit.  We had an extra "Softrock Ensbemble II" receiver on-hand (it had been the "75PH" receiver prior to the recent upgrade) which was reconfigured, putting it approximately in the middle of the 10 meter beacon subband.  All that was available was the 96 ksps sound card on the servers' motherboard - and this receiver lacks a stage of RF amplification so it is going to be somewhat deaf, but it should hear 10 meter beacons during even moderate band openings.

• 19 March, 2018.  Comments:
• Resolved issue:  There was a "hummy" spur that drifts about on the 40PH band.  The cause of this was unknown - and the symptoms were a bit perplexing:  It was not super strong (only about "S-9") and weirdly, its image (equidistant from the 7221kHz center frequency) was only 6-10dB weaker.  If this spur were on-frequency I would have expected that would have been much stronger than it was and also that the image would be 40+dB weaker.  The implication of this was that this spur is probably far off-frequency and what we were seeing was a rather weak spurious response from that (very-strong!)off-frequency signal.  The signal path contains a large number of filter elements and there are several post-filter RF amplifiers and it is likely that one of these had "broken into song":  The amplifier design that is used should  have been unconditionally stable, but all bets are off when Murphy is involved!  The "fix" was to add some 2dB resistive attenuators to the outputs of these signal amplifiers.
• Upgrade:  The opportunity was also taken to add an amplifier stage to the recently-added 17 meter receiver, allowing it to hear the background ionospheric noise.
• Under investigation:  The TCI 530 antenna was given the "shake test" and it was verified that there is, in fact, some sort of intermittent connection.  There is strong evidence that one of the active antenna elements is close enough to touch a guy wire when the antenna is vibrating due to wind.
• Experimentally, 2-meter coverage was added to the system.  At this time the antenna is not very good, so effective system sensitivity is quite poor.  This site is approx. 70 miles (112km) north of Salt Lake City so the signals from the repeaters in the metro area are a bit weak with the current configuration.  We are will be making some improvements to the antenna system which may make it more useful, but whether or not 2 meter coverage will be a permanent part of this system remains to be seen.

• 18 March, 2018.  Significant system upgrades/modifications:
• Upgraded power:  A UPS with a built-in ferroresonant transformer was added to clean up the power and provide continued operation in the event of brief outages.
• Upgrade - 160M:  Levels were readjusted and this receiver retuned and moved to a 192 ksps card to cover nearly 96% of the 160 meter band.
• Upgrade - 80CW-80PH-75PH:  A "triple" receive module was constructed that cumulatively provides complete coverage of the 80/75 meter bands.
• Addition - 80CW:  The the aforementioned module, this band was added, completing coverage of the entire 80/75 meter amateur band.
• Resolved issue - 75PH:  The sound card was modified (the "Aux" input was made available on the rear panel of the Asus Xonar DX) to allow gain adjustment and the audio levels were properly set to fix the problem where the sensitivity at the extreme edges of the band was reduced by 10-15dB.
• Upgrade - 40CW:  This band was moved to a 192ksps card and the center frequency re-tuned, now providing coverage to the entire 40 meter amateur band.
• Tweak - 630M-AM-160M :  Levels adjusted, improving weak-signal performance
• Tweak - 60-49M:  Levels adjusted, improving weak-signal performance - particularly during the daytime.
• Upgrade - WebSDR Server #2 (Green) was added, providing:
• 20M:  A dual high-performance 20-meter receiver module which, with a pair of  192ksps sound cards provides full coverage of 20 meters.  The change to higher-performance, narrow-band receivers resulted in the loss of the (incidental) reception of the 22 meter shortwave broadcast band.
• 17M:  The 96 ksps sound card that had previously been used for 40CW was installed in this server.  Redeploying the original 80PH receiver allows nearly 96% coverage of the 17 meter band.  At the time of installation it was noted that this receiver was slightly deaf, so an amplifier will be added to its signal path during the next site visit.
• 30-31M:  Coverage of the 31 Meter shortwave broadcast and the 30 Meter amateur bands was added using a (low performance) RTL-SDR Dongle.

• 12 March, 2018.  There are some ongoing upgrades to the network infrastructure that provides connectivity to the WebSDR.  Because of this work, there will be occasional network outages - typically of 4-10 minutes duration.

• 4 March, 2018. A modification was made to the code to "brighten" the waterfalls, particularly during the times of day when the bands were "dead".  At about this time additional "Passband Tuning" controls were added as well.

• 28 February, 2018.  This WebSDR was moved to its designated site - an old HF research site near the town of Corinne, Utah, about 70 miles (94km) north of Salt Lake City.  The antenna at this site is a TCI-530, an omnidirectional Log-Periodic antenna - the same model as that used at the KFS Web Site at Half-Moon Bay, CA.  Now that we have the initial system running, we will work to improve the overall receiver performance, add more bands and do more performance tweaks.  While the person in charge of the data networks lives fairly close to the site, the one in charge of the RF infrastructure lives about 70 miles (and a 75 minute drive) away - a fact that can sometimes complicate dealing with the latter types of problems.

• 23 February, 2018:   Several items:
• The system was down for several hours while some of the critical components were "racked up" - that is, removed from their temporary location (scattered across a workbench) and mounted/wired on shelves in an equipment rack.  This process is not yet complete and a few more brief outages will occur in the next several days while things are "permanentized."
• The tentative date for installation of this system at its "permanent" site is 28 February, 2018.  When this happens, this system will be down for several hours as it is relocated and installed with subsequent debugging of the computer, RF subsystems and the network.  The IP address will change at this time but there will be another server at the address of the old one that will inform those users who land there, giving the new address and prompting them to update their bookmarks.  This "informational" server will be online for a few weeks before being turned off.

• 21 February, 2018:  The hard drives on the system started throwing errors were replaced with Solid State drives, necessitating a complete rebuild of the operating system.  This process took some time and the system was unavailable during for about a day.

• 7 February, 2018:  The 40 meter receive system was reconfigured:  A custom-built dual 40 meter receiver module was used to replace the two "Softrock Ensemble II" units that, together, had covered 40 meters.  The Softrock Ensemble II units were then reconfigured to provide coverage of the bottom 96 kHz of the 160 meter band and chunk of the "80 meter" phone band.  

• 17 January, 2018:  This WebSDR server was first made public from a testing location near Salt Lake City, Utah, U.S.A. and was used to test software/hardware configurations prior to the installation at a quiet receiver site in Northern Utah.  This location was somewhat "RF noisy" with the amount of noise varying wildly at times, so it didn't hear particularly well - but it still did better than many home installations.
  

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Additional information:

• For general information about this WebSDR system - including contact info - go to the about page (link).

• For technical information about this WebSDR system, go to the technical info page (link).

• For a list of questions and answers, visit the FAQ page (link).

• For more information about the WebSDR project in general - including information about other WebSDR servers worldwide and additional technical information - go to http://www.websdr.org 

Back to the Northern Utah WebSDR