[aprssig] FW: FM Squelch blocks everything!

Kenneth Finnegan kennethfinnegan2007 at gmail.com
Fri Feb 3 10:00:18 CST 2017


So since this one battery charger has burned you several times, and is
clearly emitting an unacceptable amount of RF noise, you've removed it from
service and disposed of it, right?

--
Kenneth Finnegan
http://blog.thelifeofkenneth.com/

On Fri, Feb 3, 2017 at 5:58 AM, Robert Bruninga <bruninga at usna.edu> wrote:

> Fired up our next UHF cubesat card for first test and the ground station
> got full S9 carrier but signal was full of noise totally masking the data
> tones.
>
>
>
> Turned off.  Channel was clear. Then opened squelch and there was S9 noise
> over 5 Mhz around our UHF downlink.
>
> Went down the  halls with HT and signal tapered slowly down in all
> directions.
>
>
>
> Came back and with 1” of wire in the HT antenna connector narrowed it down
> to a cheap battery charger.
>
>
>
> Lesson over and over again, is that a squelch HIDES everything  Even 20+S9
> noise sources.  Zero bars while squelched.
>
>
>
> Reminded me of when we had local repeater problems.  Turns out it was the
> megawatt balloon radar operating in VHF looking over Washington DC.  No one
> could hear it with their radio squelched.  But open the squelch and every
> channel throughout 2m would show 60+S9 bars on the noisy trash.
>
>
>
> It was similarly baffling at the peak of packet in the 90’s when some hams
> would complain that their packet system wasn’t working, and yet they never
> turned up the volume to listen by ear to the channel to see what was going
> on.  I still see that sometimes in our students who think that all you have
> to do is hook-up two wireless thingy’s and is should just work… but never
> think to listen to a channel or use a spectrum analyzer to see what they
> are dealing with.
>
>
>
> Turns out, this battery charger (now that I remember) was the SAME one
> that got me several years ago.  I was just too old to remember until I had
> again done the full DF search through the entire academic building and
> ended up right back at the same point.
>
>
>
> The older we get the more we have to learn over and over again ;-)
>
> Bob, WB4APR
>
>
>
>
>
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>
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