[RFI] Subject: Re: Recommended Handheld VHF-UHF Yagi?

[N1BUG]

On 06/23/2014 05:00 AM, KD7JYK DM09 wrote:
> 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.

I have a modified MFJ-856 which I found near useless out of the box. 
After modification it is better. It has a very deep, sharp null at 
90 degrees (off the side) which is more useful for confirming a 
source than the broad front peak. Information on the modifications 
can be found here:

http://blog.n1bug.com/2012/06/14/

> I've gone as high as 950 Mhz search for RFI.

Going higher in frequency helps a lot. I was able to confirm the 
pole for a few sources using 445 MHz where 135 MHz was ambiguous 
even using the null. I now have one of the old CATV signal meters 
which tunes up to 900 MHz. I eventually want to build a log periodic 
covering as much of the VHF/UHF range as possible while still being 
small enough to carry around, but will probably still carry a couple 
of UHF due to their narrower beam width.

-- 
Paul Kelley, N1BUG
RFI Committee chair,
Piscataquis Amateur Radio Club
http://www.k1pq.org