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Fighting OTH radars

Maybe some of you knows this little trick but, as time as no one says it here, I think it will be useful:

I’ve discovered recently that the noise blanker function, designed initially to cancel spark noise coming from motorcycles or cars, is very effective for cancelling the OTH radar’s noise. And as time as today there is an inflation of OTH disturbing ham frequencies (and nobody cares outside our ham radio world…) it might be very useful to use the NB to be able to hear not only the weak signals but also the strongest ones. In my video, the station you can hear is OA4DVC from Peru coming very strong in Romania, but no chance to hear it without NB. Good to know…

YO2MSB youtube channel


That’s interesting Soren,

When the Woodpeckers first started breeding on air there were specific NB designs published to synchronise with the radars prf and kill the Rx for a short period matched to the OTHR pulse length. Modern noise blankers might be better than the original designs that were designed for ignition interference. I must check next time the pests are heard. Thanks for the heads up.



The blanker in some radios (IC7610 is one) can be adjusted for blanking depth and width. This allows for very good blanking of woodpecker pulses, but does mean the receiver is susceptible to distorting signals due to other signals in the blanker passband, which is over 100 khz in most radios. So somtimes the clever blanker has to go off.

The kX3 blanker and Noise Reduction functions also have adjustable depth. I am not sure if they are fully effective on the pulses from OHR.


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