[RFI] Bad QRN on HF

[Michael Tope]

Hi Dana,

If you haven't already done so, you might try using Spectran:

http://www.sdrham.com/

It provides a waterfall display and recording capability. The waterfall 
can help determine if there are any dominant spectral components 
although the recording sounds like you say a "sputtering, arcing, mess", 
so a spectral analysis may not be useful.

I would try turning on AGC or reducing RF gain. From your recording it 
sounds like your receiver audio was distorting pretty badly. It will 
probably still sound like crap without the extra distortion, but it may 
be more easily recognized by somebody who has been troubled by a similar 
source.

It might also be helpful to figure out how high and low this QRN extends 
in frequency. If it is still prevalent at VHF, you might be able to 
sniff for it in a mobile with a small yagi.

If there some diurnal variation, that would be worth investigating. For 
instance, if it starts getting worse in the late afternoon, what time 
does it start getting better? How quickly does it build and decay. Does 
it persist constantly over that period or does it cut out periodically?  
All those little bits of information could prove useful towards matching 
it up with potential sources (e.g. an HVAC source would likely cut in 
and out because of  the thermostat).

Wish I could be of more help. QRN is no fun especially when you have 
gone to the trouble of putting together a remote station to get away 
from urban noise. That must be very frustrating.

Good luck,

Mike W4EF/6...................


On 8/14/2010 7:49 PM, Dana Roode wrote:
> Folks,
>
> Don't know where to begin - I have several bad sources of QRN at my
> remote desert location, the worse one seems to come on from the East
> starting in the late afternoon.  Makes 20M down pretty unusable.  I
> tried a recording if anyone wants to listen for immediate thoughts:
>
>     http://roodes.com/k6nr/20m-7PM-AM-NOAGC.wav
>
> Sputtering, arcing, mess - I dont know if its from the power lines or
> the neighbors.  We are on 2.5 acre lots so the neighbors are not real
> close.   I recorded in AM, no AGC, if there is a better way to do this
> let me know, unfortunately its easy to get additional samples.
>
> Does anyone know of an individual in Southern California that could
> help me sort out my various noise problems?  Southern California
> Edison has been out multiple times trying to resolve a different noise
> (from the NorthWest).  Each time the inspector finds what he thinks is
> the cause, then I wait 3-6 months for a crew to come out, they fix
> what the inspector found, but my noise remains.  It doesnt help that I
> live 80 miles from my station either.
>
>    Dana
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