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
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