[RFI] tips for finding the source of broadband mixing products

JW jwin95 at yahoo.com
Sun Sep 29 22:48:47 EDT 2019

 How are you determining all this - you do realize, in close proximity to
a transmitting rig, much (albeit low-level) RF comes straight out the 
power leads and can 'modulate'/be modulated by the power supply 
energy that also escapes, including simple rectifier supplies using only 

We demonstrated this at Heathkit several different ways, including using
a spectrum analyzer to 'sniff' the stray RF coming back out via the radio's 
power cable WHICH in turn was modulated and showed 120 Hz sidebands ...

de AA5CT 

     On Sunday, September 29, 2019, 9:00:49 PM GMT-5, Matt NQ6N <matt at nq6n.com> wrote:  

I'm noticing that the second harmonic of my transmitted signal is
accompanied by all sorts of broadband noise.

I am in the process of ruling out the equipment inside the shack as a cause
of this noise.

But I want to be prepared to begin the search outside the shack for things
(wall warts, etc.) that might be generating the broadband noise when
exposed to RF.

What are some techniques for localizing the causes of this kind of
broadband noise?

A screen shot of the pan adapter and a recording of the audio of the third
harmonic + noise is attached via the below link:


Any advice would be much appreciated.

Matt NQ6N
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