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Re: [RFI] HF DF Antenna recommendations

To: rfi@contesting.com
Subject: Re: [RFI] HF DF Antenna recommendations
From: "K8RI (Roger)" <K8RI@rogerhalstead.com>
Date: Mon, 17 Jan 2011 21:51:46 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On 1/17/2011 9:17 PM, Frank N. Haas KB4T wrote:
> As some of you know, I am an interference investigator for a large Florida
> electric utility. I am fortunate that my employer has provided me with the
> best tools available to locate and pinpoint real sparking power line sources
> that can easily be found at VHF frequencies.
> Users of the HF frequencies are frequent customers. Some of these cases end
> up being HF only sources that can't be heard at VHF. Only one of my several
> antennas is designed for HF direction finding. It is large and unwieldy.
> After reading some old articles about ARDF 80M handheld DF units, I'd like
> to find something better suited to my needs.
> I'm curious if anyone on this list has any experience with HF DF antennas of
> any sort. For the last several years I've been using the G4TPH magloop for 3
> to 21 MHz searching. The loop works well but it is large and a nuisance with
> which to work. When I have to take multiple readings/bearings in a fairly
> short period, the big magloop is too much trouble. There has to be a better
> way.
This goes *way back*, but I used to use a Singer Metrics system.  The 
receiver weighed a ton...OK about 70# +/- but the antenna when went on a 
wood tripod was only about a foot in diameter. I used that from 100 KHz 
to around 30 MHz although my primary interests were from 100 KHz to 
around 7 MHz.

The antenna was quick to set up but that old receiver wasn't.  It looked 
like military portable gear although the company purchased it new.

Some of that old RF induction heating gear had to be watched pretty 
close and I had marked spots where I took readings and noted headings.

I also used the mobile ham rig, but directive it was not.

> I've read about products like the National RF Model HFDF and the Cubic
> Communications Model HH1307a. Both are active handheld HF DF antennas. The
> former retails for about $240 with a full complement of loops while I
> haven't found a price yet for the latter. Since the HH1307a is a military
> product I can only assume that it is very expensive.
> I wonder, is there anything in the middle?
> What tools do other pro's use for HF searching? I have good portable and
> handheld receivers. The antenna is the hard part.
> So... do any of you have any experience with the 2 products I've mentioned?
> Perhaps one of you can recommend something?
I'm afraid my work along these lines is pretty dated, kinda like me.  
When I was doing DFing equipment like that came on wheels, or it took 
two strong men to make it portable.  OTOH the antenna probably was not 
much heavier than the hand held unit above.

Gettin' old is a Bi**ch, but getting here was fun.


Roger (K8RI)
> Thanks for your input.
> 73,
> Frank N. Haas KB4T
> Utility Interference Investigator
> Florida
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