Pulsing Inerference Question..


David KK7SS <d3j452@...>
 
Edited

When I am on 40M I get a pulsing effect on the baseline noise level plus it affects the AGC.
I found this is because of a strong carrier on 6.750 MHz sending out a pulse about every 1 second.
This is in a frequency segment supposedly reserved for Aviation purposes

I do not know where this is based and I can't find it on any FAA maps.
It's too close to the start of the 40M band for a Rx filter to catch it..
Any suggestions on how to "notch" it out would be appreciated..

Dave KK7SS


Clint Chron
 

Hi Dave,

 

I suspect that the 6.75 MHz signal is local to your QTH.  You could make a LC notch filter to notch out the signal.  Since it is LC, it would be fairly wide, but as long as it does not degrade the signal at 7.0 MHz, then it should take care of the problem.

 

73

Clint

W7KEC

 

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of David KK7SS
Sent: Sunday, July 12, 2020 3:58 PM
To: EladSDR@groups.io
Subject: [EladSDR] Pulsing Inerference Question..

 

When I am on 40M I get a pulsing effect on the baseline noise level and affects the AGC.
I found this is because if a strong carrier on 6.750 MHz sending out a pulse about every 1 second.
This is in an frequency segment supposedley reserved for Aviation purposes

I do not know where this is based and I can't find it on any FAA maps.
It's too close to the start of the 40M band for a Rx filter to catch it..
Any suggestions on how to "notch" it out would be appreciated..

Dave KK7SS