RFI
[Top] [All Lists]

Re: [RFI] RFI all over the band

To: "RFI List" <rfi@contesting.com>
Subject: Re: [RFI] RFI all over the band
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 02 Oct 2006 11:10:42 -0700
List-post: <mailto:rfi@contesting.com>
On Mon, 2 Oct 2006 23:27:02 +0530, Ramakrishnan Muthukrishnan wrote:

>I do not have a HT with AM mode, perhaps I will try to borrow one.

I agree with others that this is a very useful tool in chasing down 
RFI. 

Consider this basic principle. For low frequencies, the entire 
length of a long power line will be the radiator, so direction 
finding will simply point to a very broad line source. At much 
higher frequencies, the portions of the line more distant from the 
source tend to be decoupled from the source, so the segment of the 
power line nearest to the source of the noise is what produces the 
strongest radiation. Thus, for broadband sources like arcs, that 
have content in the VHF or UHF range, a VHF receiver will provide 
far more precise information about the source of the noise. 

This advice is quite different for noise sources that have little 
VHF content, such as oscillators and computer clocks running at low 
frequencies, or clocks that are better suppressed at VHF/UHF but not 
at HF. Obviously, it's much harder (or impractical) to go looking 
for a source that either doesn't exist at VHF or is much weaker at 
VHF. 

73,

Jim Brown K9YC


_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi

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