Topband: 160m Jammer

Tom Rauch w8ji at contesting.com
Fri Jan 19 14:09:38 EST 2007


So far:

>>  160 Meter Radar Noise:
>> http://www.k8nd.com/Radio/160M_RADAR_NOISE.wav
>
> That sounds like a local digital device and local power 
> line
> noise.

Tree sent me this link, which sounds just like the noise 
VK3ZL let me listen to about a year ago:

http://www.kkn.net/~tree/160/160Radar.wav

Bob described it as a "diesel engine idling".

None of this is positive of course, it is just speculation 
based on what I know about systems like this (I designed 
some OTHR pulse generators and amplifiers in the past as a 
subcontractor so I have some pulse specs from early HF OTHR) 
but the stuff on the first link sounds more like power line 
noise in combination with some digital device using clocking 
than anything intentionally generated for pinging or 
jamming.

1.) The second noise at Tree's site would be 100% blankable 
if the pulses are sharp. I suspect they are and Tree's 
receiver selectivity was making them ring. If so, it could 
be removed at any location.

2.) The noise at the K8ND site duty cycle is too long and 
has a pattern of two pulses then a gap (like arcing in two 
phases of a three phase power line) to bank. It would have 
to be nulled.

This is just my best guess at this time. Hopefully I'll get 
a recording on somewhat wide selectivity from Japan. The 
wider the selectivity the better!

73,
Tom





More information about the Topband mailing list