>>>>
There are disadvantages in using too high a frequency in trying to locate RFI
sources. The RFI signal does not travel as far at UHF as it does in the VHF
range.
The power lines here are at the back of property lots about 150 ft. from the
streets. One time I was able to pick up an RFI noise from the street with my
HB 3 element yagi and and an aircraft monitor receiver operating on about 135
Mhz. The power co. guy could not hear the noise with his multi element yagi and
commercial equipment from the street operating in the UHF range of about 300 or
400 Mhz. Only when he walked to the back of the property and got within about
50 ft. of the source could he pick up the could he pick up the signal.
Don
K9MUF
<<<<
----- Original Message -----From: KD7JYK DM09 <kd7jyk@earthlink.net>To:
qrv@kd4e.com, rfi@contesting.comSent: Mon, 23 Jun 2014 09:00:07 -0000
(UTC)Subject: Re: [RFI] Subject: Re: Recommended Handheld VHF-UHF Yagi?
: Which number of elements on VHF is considered adequate?:: 3-el: 4-el: 5-el:
6-el: 7-el
I've played with a couple of 3 element "noise locators" on VHF, both were
useless, no directivity at all, OR, RFI was everywhere. Couldn't tell, went
back to a vertical sense antenna and attenuator and located it that way.
Power companies use a UHF 5 element Yagi around 320 MHz. It's small, light and
adequately narrow beamed.
If you have a broadband HT with selective RX mode, such as the Yaesu FT-60 that
I use, consider using a higher frequency. It'll be easier to pinpoint noise and
the antenna isn't too bulky. If you will be dealing with a power company, use
the range they do, at least it'll be something they might understand, "Oh, that
guy has stuff just like ours".
I've gone as high as 950 Mhz search for RFI.
Kurt
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