[RFI] Rfi help

[Kenneth G. Gordon]

On 16 May 2020 at 13:06, Randy Davenport wrote:

> I have terrible RFI on the hf bands.  I can't find it but somewhere I read
> that rg213 jumpers  reduce the RFI
> 
> Is it true?

That MAY be true in certain, probably very specific, instances. It is NOT generally true. 
RG-213 has two shields so this will, possibly, help if the jumpers you are presently using 
leak badly, but that is not generally the case.

Your first action MUST be to identify the type of RFI, then to determine the source, and 
lastly, to fix the source.

There are folks here who can help you with that, depending, somewhat, on where you are.

Start by doing the following.

What kind of rig is involved, BTW?

Does the noise still exist with the antenna disconnected from your receiver? Is the noise 
much stronger with the antenna connected? If the noise is external to the receiver, it will be 
the latter. If you have or can borrow a second receiver, does the noise appear to be 
identical in that second receiver?

First of all, what is the signal strength (S-meter readings) of this RFI measured on all 
effected bands? Usually, but not always, RFI is worst at the lower bands, and falls of as one 
goes up in frequency. Make a table or list. 

Carefully go through each band, making sure your antenna is peaked to the band in 
question, and write down in a table what you find.

Then, if you have or can get some sort of receiver with a waterfall incorporated in it, see if 
you can identify some type of recurrent characteristic of the noise in the bands, since 
sometimes such RFI will peak, broadly or narrowly, in certain specific parts of bands. 
Othertimes it is totally broadband. Take photos of some sort of what you see to post to us 
later.

Then, set up your receiver on the loudest, strongest noise, then turn off the breakers or 
remove the fuses to each of the separate circuits in your own home, one at a time, leaving 
those you have turned off still off until you have completed your "survey". The noise MAY 
BE coming from something local, i.e. in your own home. If your receiver can be so set up, 
run it on a battery source for this.

Write EVERYTHING down.

Report back here after all of the above.

Ken W7EKB
Idaho