Ouch indeed......
In listening to your file it sounds like power
line noise. There have been many good articles on
the rfi reflector about this type of noise. A
simple portable radio can get you started on the
source location. In addition do a search on QST
articles for more detailed procedures.
Smith Bradford
W9HAK
Knut Spang wrote:
> Hi,
>
> Ouch, when I came home from work today I had an S5 level of noise that
> somewhat resembles your recording, but not quite the same. I have
> attached a recording. The first minute or so is in AM mode, the
> remainder is USB. Do you think this might be a plasma TV? The K3 noise
> blanker does not do a stellar job of suppressing it (on power line noise
> it does). It's not from my house (breaker test) but definitely from my
> block. This is a terrible development. The spectrum is very flat with
> very few bumps as opposed to yours. I have never had anything like this
> in my location before.
>
> AB2TC - Knut
>
>
> On 11/28/2010 5:49 PM, W9HAK wrote:
>> Good evening Knut,
>>
>> The sound file was recorded this evening on 7.120. I can hear it all
>> the way down to 7.000 mhz. Due to the contest I picked this frequency
>> so it could be clearly heard.
>>
>> The P3 display is also centered on7.121 mhz. The scan is 10 khz plus
>> and minus. The noise floor is roughly -110 db and as you can see the
>> peak of the plasma noise is -95 db. When the bands are quite the
>> plasma signal is grouped in clusters across much of the hf spectrum.
>> Depends on how your antenna is exposed to the front of the tv set.
>> Thankfully my antenna sets behind the tv set and is a 100 feet away.
>>
>> As the video changes the pulses you see change, and the sound follows
>> suite. A total pain in the tail feathers. There is no cure that I am
>> aware of. I can work around it somewhat with the K3, but my Collins S
>> Line really takes a hit. In the narrow cw filter, (200cps), it's
>> doable on most signals. But you can forget ssb operations if the
>> cluster falls on the frequency you are trying to use.
>>
>> Smith Bradford
>> W9HAK
>>
>
>
> ------------------------------------------------------------------------
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1382 / Virus Database: 1513/3720 - Release Date: 06/22/11
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|