Nothern Utah WebSDR Logo - A skep with a Yagi Northern Utah WebSDR
Receiving equipment
WebSDR #4 RF distribution and filtering

In early April, 2020, the Northern Utah WebSDR commissioned a new server - WebSDR #4 - that is connected to a different antenna - an LP-1002 (made by Hy-Gain, now U.S. Antenna Products) that is a 6-40 MHz log periodic direction antenna that is oriented on a heading of 87 degrees (relative to true north).  To do this, new RF infrastructure needed to be designed and constructed to deal with the specific needs of this new subsystem.

Figure 1:
The signal path of the RF system used on WebSDR #4.
The "LF/HF Diplexer + HF Amp" unit is located at the base of the tower while the remaining equipment is located in the building with the server gear.  As noted, the cable between the tower and the building carries LF signals and DC to power the LF active antenna and the outside RF amplifier.
Click on the image for a larger version.
RTL-SDR Blog USB receiver, used for HF through UHF
This system consists of two major parts:

Dealing with large signals:

Those familiar with HF propagation are well aware that there are time during which certain shortwave broadcast signals can become extremely strong.  During the "low" portion of the 11 year sunspot cycle, this is most likely to happen on the lower bands such as 60, 49, 41 and 31 meters.

While Utah is more distant from the "powerhouse" Shortwave Broadcast signals found in the Eastern U.S., there are certain times when such signals will peak - and this typically happens around the time of evening "grayline" propagation - that is, the hours during which sunset is moving across the North American continent.

It has been observed that some of these signals will peak to well over -20dBm at the antenna terminals - a signal level that correlates to "50 over S-9" or higher - and there are often several of these very strong signals - and the total RF power of these signals - plus the modulation peaks - combines to instantaneous levels that can significantly exceed that of any, single signal.  As you can imagine, this amount of total RF power can cause issues with even "strong" receivers by several mechanisms:
As implied above, there are several ways to deal with these issues:

Receive equipment on WebSDR #4:

The receive equipment used on WebSDR #4 is similar to that used on WebSDRs 1-3:

Pages about other receive gear at the Northern Utah WebSDR:
Go to the main "RX Equipment page.

Additional information:
 Back to the Northern Utah WebSDR landing page