On 10/1/2025 3:35 PM, Christopher Wawak wrote:
Tune to an unused frequency in the AM band where you can hear the noise.
Then, start walking around your property, neighborhood, etc. See where it
gets louder or softer.
Alas, like many urban hams, I've had way too much experience tracking
down RFI.
With all due respect, an AM radio is not likely to be helpful. The
problematic interference may not be audible in the AM band, but many
other sources probably will be. Even if you can hear the correct source,
the AGC of the radio will make it very difficult to tell whether it is
getting stronger or weaker.
For RFI other than power line noise, I've had the best results using a
handheld HF receiver tuned to the same frequency as the station radio.
If the interference is somewhat stable in frequency, that may allow you
to make sure you're listening to the correct source. If there's any sort
of modulation, that may be another way to identify the right source. A
telescoping antenna is helpful: by shortening it until the RFI is right
at the receiver noise floor, you can tell if you're getting closer.
For tracking power line noise, I've used a VHF tracking receiver. To
identify the correct source, I have a licensed friend relay the AM audio
from the station receiver on 2 meters, so I can hear it at the same time
I'm listening to the tracking receiver. (Latency of a cell phone will
render it useless.) There is almost always an audible pattern to line
noise, so I can tell when they match. That's very important; otherwise,
you will waste a lot of time tracking down the wrong noise sources, of
which there will be many.
73,
Scott K9MA
--
Scott K9MA
k9ma@sdellington.us
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