Topband: DX WEB SDR re-transmission from Europe

[YL2VW]

Hi

I would like to bring to the attention of topband community the fact that
some folks in Europe, either by accident (computer sounds transmitted
accidentally due to VOX being ON) or on purpose (DQRM? "helping" others to
receive DX?) are time to time re-transmitting remote location WEB SDR audio
on 1840 kHz.

It certainly happened 29.oct around 21:00Z , when somebody was
re-transmitting some JA Web SDR on 1840 kHz from Europe  - 1840 kHz in
Europe suddenly was full of JA signals, who never should transmit on this
frequency.

It likely happened again on 30.Oct between 17:53Z and 18:05Z. This time
some European guy was re-transmitting some VK SDR . (VK4MA signal
sudden/stable improvement from -10 db to 0 db; and VK9NG signal sudden
appearance with good levels).

The ways to detect that it takes place I have found:
1) using waterfall - when this happens, in waterfall weird background noise
pattern is visible (at least in these 2 cases) in whole FT8 spectrum.

2) using audio - weird audible noise appears in whole FT8 spectrum, but DX
signals still make  through it (suspicious, isn't it?)

3) extra time offset of DX signal (DT value)  - re-transmitted signals have
extra time offset... +0.5... +1 or more compared to real signals. Extra
delay can be explained by delay in Internet transmissions between remote DX
WebSDR receiver and local re-transmitting PC. For example, in the above
mentioned case on October 30 VK4MA signal time offset jumped from 0.1
before to 1.7 after re-transmission started and the very same moment his
signal level jumped from -10 to 0 at 17:53:45 Z.

4) those who have directional RX antennas, could potentially notice that
signals come from wrong direction, but it depends if direction of repeater
is different from DX path.

5) looking in pskreporter.info or similar source one could see fantastic DX
signal levels reported from some spots in Europe. In case of 30.Oct VK SDR
re-transmission, the level peaks seemed to be around DL/HB (VK4MA signal
was received with +12...+13 levels there).

I now also suspect that not always this re-transmission is accompanied by
visible or audible noise patterns (points 1 and 2 above) - it probably
might depend on how good re-transmitted signal levels are adjusted on
"repeater" PC. But may be I just became paranoid.

So, please be cautious when making conclusions like "Tonight was super DX
propagation for X minutes/hours".

Looking back in my JTDX ALL.TXT log I suspect this has happened before
already few times with somebody re-transmitting USA SDR from Europe, when
there have been sudden short-term improvements in NA signal levels in
Europe, which now seem to be accompanied by this weird, otherwise
unexplained extra 0.5-1 or more second time offset of all NA station
signals compared to EU stations. If one would try to explain this delay
with normal physics, like bouncing signal, ionosphere tunnels or something
like that, to get extra 0.5 second delay signal would need to travel extra
about 150 000 km (Earth perimeter is about 40000 km for comparison). So
this sounds not plausible. Unless I am missing something. But if someone
has some good other explanation of why USA signals (not one, but all or
vast majority) for some periods of time could have extra 0.5-1 s time
offset in FT8 compared to average EU signals, will be glad to discuss that
in private email (will summarize here, if there will be anything to
summarize).

If these folks, who are doing these re-transmissions, read my email:
please stop doing it. It is not fun at all, actually it is violation of
your amateur-radio license terms. Anyway - by doing this you are preventing
other fellow topbanders to enjoy their hobby honestly. If you cheat
yourself by using remote WEB SDRs, it's your decision. But don't enforce it
to others. Also such re-transmissions will distort the conclusions made by
those who are using FT8 signal monitoring to study topband propagation
dependencies on Solar weather, for example.

73!
Agris/YL2VW