[Top] [All Lists]

Re: Topband: RFI

Subject: Re: Topband: RFI
Date: Thu, 25 Jun 2020 13:20:33 -0400 (EDT)
List-post: <>
Hi Fred, 

Google: 160 meter receiving loop antennas 

You'll get lots of good ideas for antennas you can build in 
just a few hours with simple parts. 

An 8 foot diameter loop will provide the best sensitivity, 
but a smaller 4 foot loop will provide deeper nulls 

You'll need a good preamp and detailed attention to 
common mode suppression. 


----- Original Message -----

From: "Fred Moeves" <> 
Sent: Thursday, June 25, 2020 5:16:43 PM 
Subject: Re: Topband: RFI 

Thanks everyone for the help/info. 

The noise is there almost all the time the only time it stops is when it 
In my video the it just stopped raining and it was just getting going again. 
I wanted to show the noise when it was not there too. 

I know one of the guys who are involved in finding the pole. 
I am working on the other two guys...I do have the main guy's cell so 
that's a step in the right direction. 
And they do seem to care and want to solve the problem. 

Thanks Tim for the graph and the good ideas. 

Don I thought I had it down to 2 different poles but they said it was 
not there. 

I have 2 portable SW radios they will not receive the noise. 
But if I connect my 40m full wave loop I can hear the noise. 

So I think I have to come up with a good portable antenna maybe a small 
multi turn loop. 
I have Hustler RM-40 resonator. 
I hooked it up stood on my upper deck but can't hear it. 

Well that's about it...73 and thanks 

Fred KB4QZH 

On 6/24/2020 7:03 PM, Tim Shoppa wrote: 
> Fred, I graphed the scope trace of your noise in the video you linked, 
> it is definitely 120Hz impulse noise. Attempting to attach scope 
> picture. Count 12 spikes in 0.1 seconds = 120Hz. Very likely the power 
> line guys can find it if they come at a time when the noise is there. 
> Now if it's intermittent (like I hear) getting the power line noise 
> experts to show up on a day when the noise is there is the magic. In 
> the best world they have your phone number and call before they show 
> up, and you have their phone number and can tell them if the noise is 
> there for them to trace. 
> Sometimes intermittent noises burn themselves out but more likely it 
> gets worse over time and become solid 24x7. 
> Most rigs have noise blankers that help in the face of 120Hz impulse 
> noise and not-crowded bands. Noise blankers are harder to use 
> effectively in thick dense signal environments like contests but 
> progress has been made with advanced noise blanking techniques. There 
> was a truly excellent article in NCJ by N2NC on advanced SDR 
> techniques in contest situations. 
> image.png 
> Tim N3QE 
> On Wed, Jun 24, 2020 at 6:13 PM fmoeves < 
> <>> wrote: 
> Thanks Steve. I think my power line guys need some training.. I 
> wish I could use their detector for an hour or so. They keep 
> telling me my area is very clean. I'll drive around some more see 
> what I can hear. Thanks Fred KB4QZH 
> -------- Original message --------From: Steve Lawrence via Topband 
> < <>> Date: 
> 6/24/20 5:21 PM (GMT-05:00) To: fmoeves < 
> <>> Cc: Top Band List List 
> < <>> Subject: 
> Re: Topband: RFI Look here. GL - Steve WB6RSESounds of RFI 
> <>On Jun 24, 2020, at 1:44 PM, 
> fmoeves < <>> wrote:Hoping 
> someone can help me identify this noise.It's on 160 80 40...most 
> times stronger on 40.I called the power company..they found 
> nothing.The video is just after some rain. When it rains it goes 
> away. 
> Fred KB4QZH _________________Searchable Archives: 
> - Topband 
> Reflector_________________Searchable Archives: 
> - Topband Reflector 
> _________________ 
> Searchable Archives: - Topband 
> Reflector 

Searchable Archives: - Topband Reflector 

Searchable Archives: - Topband Reflector

<Prev in Thread] Current Thread [Next in Thread>