[TowerTalk] Weird RFI at remote location

Ron Young W8RJL youngron at verizon.net
Sat Jan 2 23:10:53 EST 2021


Remember that if you have any UPS units they will continue to run when your main power breaker to your home is turned off. Sometimes this is overlooked when searching for RFI. GL, 73, Ron W8RJL


Sent from the all new Aol app for iOS


On Saturday, January 2, 2021, 7:35 PM, K9MA <k9ma at sdellington.us> wrote:

On 1/2/2021 8:32 PM, Ignacy Misztal wrote:
> 1. The noise is originating from one location because otherwise NB
> would not be able to blanket it.

I don't think so, unless you are using some sort of noise cancellation 
with two antennas etc. Noise blankers can be very effective against 
impulse noise, typical of line noise. However, they don't work well if 
there are strong signals within a few kHz. While it's a good diagnostic 
sometimes, a noise blanker that works on a quiet band probably won't be 
useful during a contest.

Besides its impulse nature, line noise is usually quite broadband. While 
it may affect one band more than another, there generally isn't much 
variation in strength within a band. This is very unlike noise from 
switching supplies, motor drives, etc, which usually show peaks at 
harmonics of the switching frequency, often 10-100 kHz. As others have 
suggested, the difference is most readily apparent with a spectrum 
display. It's a lot harder to discern by tuning around looking at the 
S-meter, though it can be done.

Because I live in the city surrounded by overhead power lines, I have 
way more experience with line noise than I'd like. Hopefully that will 
be of some use to others.

73,

Scott K9MA

-- 
Scott  K9MA

k9ma at sdellington.us

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk





More information about the TowerTalk mailing list