On 1/28/2024 7:50 PM, Wes Stewart via RFI wrote:
Any other suggestions?
Hi Wes,
Lots here.
http://k9yc.com/KillingReceiveNoise.pdf
Broadband RF spectrum analysis, including a long time waterfall, in the
range where you're hearing it helps us figure out the nature of what
we're looking for. That is, is it arcing or electronic stuff.
We have long known the characteristics of arcing, and to chase it at the
highest frequency where we hear it. With electronically generated stuff,
we must chase it where we hear it.
NK7Z developed this excellent methodology using a low cost SDR RX ($120
at HRO). Software to run it is free. Dave provides lots of detailed
setup instructions.
https://www.nk7z.net/sdr-rfi-survey-p1/
Armed with what we learn from both this collection of information, we
use traditional DFing techniques. It provides time of day info, allows
us to distinguish between multiple sources by how they drift in
frequency. Time tells us when to look, identifying the different sources
can prevent us from wild goose chases, or even let us chase one, then
the other.
My app note lists several battery-operated tools I've used. They include
a pretty good Tecsun AM/FM/shortwave RX that sells for about $40. A very
broadcast engineer pointed me to it years ago.
If it's arcing, I have the broadband RX in both my mobile FM rig and my
talkie programmed with frequencies in the VHF and UHF range, starting at
160 MHz, and four more up to about 550 MHz where the general coverage
stops. The antenna is a vertical whip, either a mag mount or a trunk lip
mount.
Since I'm chasing arcing, I drive around tuned to 160 MHz, and as the
noise gets louder, I switch higher in frequency. When it gets really
loud, I get out of the car with the talkie at that highest frequency and
walk around. One trick I learned at one of the Fox Hunts of the
Chicago-area club of which I was a member was to hold the talkie right
against my chest, giving it a half-space pattern.
Don't limit yourself to tools you own -- check with members of local
clubs to borrow stuff.
73, Jim K9YC
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