Satgen 184  Radar QRM - RSGB Silence   by GM4IHJ           3rd October 92

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6 months ago Satgen 162 summarised reports of overwhelming QRM around
435.2 MHz wideband affecting terrestrial amateurs and satellite users
throughout Europe. One source is clearly in the UK and has the
characteristics of a Pave Paws radar (Scientific American Jan 85 refers ).
Why it had to appear directly on top of the 500 KHz segment which
contained eight operational Amsats which cost amateurs millions to build
and launch , many of which had been in space for years, was not explained.
So one has to presume either ignorance or contempt on the part of the
radar operators.In attempting to get something done two things happened :-
1. GM4IHJ got a second hand message purporting to come from G3AAJ
Secretary of Amsat UK saying " WE are dealing with it . Shut Up and give
us a chance "
2. G2UK Radio Communication RSGB magazines satellite columist wrote about
the problem for RadCom July 92. The notice about Pave Paws interference
was passed in the galley proof stage but was censored and removed before
publication, with a photograph of the previous years Uo5 launch filling
the hole created by the censorship.
So there is no doubt RSGB have been fully aware of this problem , but
chose to try to hide it from members.
Now several months later the situation is going from serious to
disasterous. The Oscar 13 controller recently published a request for
funds to help rebuild a transceiver badly damaged whilst trying for hours
in a last ditch effort to control the satellite. His attempt was defeated
by enormous radar QRM .
Earlier this week what is probably the next episode in this saga surfaced
when Oscar 13's transmitter became unstable and started FMing. Initial
reactions included "blame it on high power users". But this is not the
complete story. Oscar 13's orbit changes slowly and just now it is
hovering for at least 6 hours every day directly overhead UK, where it
gets the full blast from this monsterous radar. So that is what is
draining its battery and reducing its TX volts below the stable level.
On the rest of the satellites the problem is that of reception against a
background of massive radar QRM. I have received letters from all over
Europe and the Mediterranean ( where there is another of these radars )
complaining of days when satellites downlinking around 435 MHz cannot be
received properly.
The message for the RSGB is Clear. We ( RSGB included ) have collected
millions of pounds to build and launch these sats . Ordinary amateurs have
spent hundreds of pounds equiping their stations to use them . Most of us
subscribe to RSGB in the hope that they will protect our interest and keep
us informed. The time has come for them to crawl out from under the carpet
and do something on our behalf , and, tell us what they are doing . We are
not as far as I am aware members of a secret society. But this abysmal
performance makes me wonder whether RSGB committee think we are. 73 de
John GM4IHJ @ GB7SAN 
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