We are looking into the possibility of migrating to a platform other
than the PA3FWM WebSDR currently in use. While there are
several
options out there, the most prominent is the "Phantom WebSDR". This has
the advantage of using simpler hardware (and RX-888 or similar)
to receive HF bands, presenting the user with a single interface for
the entire HF
spectrum - much like the KiwiSDR or even the University of Twente
WebSDR, also operated by
PA3FWM.
While we have not yet "spun up" a test server running Phantom
WebSDR (it's on our "to
do" list) we are in communications
with others who have done so and
have also been trying out a few of them that
are online - but this has led us to a few observations:
It's
not stable.
Reports from others who have been testing it have reported that it's a
bit of a fight to get it going - and it requires a bit of babysitting
to to keep it working properly. In contrast, the PA3FWM
WebSDR is extremely
stable and robust.
It's a
bandwidth hog.
Whereas each, individual user of the PA3FWM WebSDR need consume only
40-50kbps of bandwidth for audio, waterfall and control, the typical
configuration of the Phantom WebSDR results in each user requiring
400-500 kbps.
To support just 200 users - which is a common load
for the
Northern Utah WebSDR - would require approximately 100 megabits of
Internet bandwidth, and that is simply not
available at the remote
Northern Utah WebSDR receive site at this time. The reason
for
this seems to be (unnecessarily?)
high audio encoding rates and an inefficient means of conveying the
waterfall display as currently implemented in Phantom WebSDR.
Requiring nearly a half megabit of also
strains the connectivity of many individual users - particularly those
who may have tenuous (e.g.
mobile
devices and satellite connections, poor connectivity overall, etc.)
Internet connections and/or "metered" ("pay per gigabyte") data plans.
Potentially
marginal
performance of a single, wide-band receiver coving all of HF.
Simply connecting a single, wideband receiver -
like a KiwiSDR, RX-888,
Web-888, Red Pitaya or similar to an antenna will likely result in
mediocre performance - particularly if this system is located in an
area with a
very low noise floor - the result being that performance of the receive
system, particularly on the upper HF amateur bands, will be rather poor
compared to a typical amateur receiver in terms of sensitivity and the
ability to handle large signal levels.
This issue is solvable -
and articles on doing this (which
may well involve constructing specialized hardware that isn't available
commercially)
may be found in the "Technical" pages of the Northern Utah WebSDR and
other places - but
the need and means of doing this may not be known to many who attempt
to use this hardware.
If you peruse the Northern Utah WebSDR's web sites you'll note that we do
cover all of HF on some receivers (KiwiSDRs)
as well as a number of the shortwave broadcast bands. Further
investigation will reveal that these resources get relatively little
use compared to the amateur band receivers. Between these
observations as well as results of surveys and
correspondence with users indicate that most users do NOT
really care about frequencies other
than
amateur bands for the most
part - and that there's something to be said about simplicity of
operation when one can simply select an individual amateur band rather
than have to pick it out from a 30 MHz wide display..
We expect that Phantom WebSDR - and possibly others -
will eventually mature to the point where they are both stable and
suitable for large numbers of users and be optimized for both processor
and network bandwidth utilization - but that day is not
yet today.
If you notice some issues that are unrelated to those
listed abovefeel
free to use
the contact info on the About
page to let
us know about it.
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
