Topband: 160m Jammer

Joe Giacobello k2xx at swva.net
Sat Jan 20 13:12:37 EST 2007


I forwarded one of the TopBand reports of the 160M jammer to Brett, 
VR2BG.  When I had visited him in VR2 earlier this year, he had 
complained of problems on several bands with jamming from the Chinese 
military.  Since he no longer subscribes to this list, he suggested that 
I clip and paste his reply for those who might be interested in his 
assessment and experiences.

73, Joe
K2XX

The recordings from BV are heavily clipped.  The
one from 160m is unrecognizable.  The file
"160Radar.wav" somebody else made is the
same as what I hear here.  It is the same as the
signal from PLA base in VR2 that I once heard.
On 80m, we have noise level here that changes
from day to day, not able to blank.  I agree with
W8JI that it's comms - different bases transmitting
at different times would fit.  But why so wide on
topband?  On 80m it is nowhere near as wide (as
judged from <2 km from the source), but had
spurs/harmonics extending beyond 15m (which I
used to DF source).  If you compare the rolloff of
BY7RADAR to something like ZC4RADAR, it's
clear the Chinese simply don't care what comes
out the spigot (like the air we breathe, the bands
are really bad now here).

The other recording is the Hainan woodpecker.  It
can be found on 20, 30, 40 & 80m.

Only JA MPT has made formal complaint to BY about
the 160m noise that I am aware of.  There has even been
an article in major JA newspaper about it.  There is a
distinct lack of 160m intruder reports coming from JA
(IARU R3 Monitoring System).  CRSA did not attend
Bangalore IARU conference - otherwise we are getting a
bit fed up with the overall situation on the bands.  What
we really needed were whinging Yanks a coupla years
ago when it all started.  Once started, these things
do not go away - ZC4 is a perfect example.  It is
rather unlikely BY will do anything differently since
the west does exactly the same thing (ignore ITU-RR).
Best thing all of us can do is file complaints about
harmful interference caused by these intruders to our
respective telecom authorities & push them to do
their job, like: http//home.pacific.net.hk/~vr2bg/hrsa
Sadly, ours doesn't seem able to do very much.

robert briggs wrote:
> Reference re wav file.........~tree/160/160radar.wav..That is the exact 
> sound appearing here in VK.It is 300Khz broad with no peaks or nulls on 
> any specific frequency 1700 to 2000Khz approx.
> I have also noted that it seems to be around a lot more recently.Pity 
> our friends in Asia.
> I note that it can be especially strong here around my sunrise although 
> I seem to be able to work through it most of the time.
> 73.....Bob..
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