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Date: Wed, 08 Aug 2007 10:33:08 +0100
From: Peter Dodd <g3ldo@ukonline.co.uk>
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Subject: Re: LF: Antenna testing
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Hi Dave,
Yes I agree with you about the cost of the AIM4710 but I needed it 
because of my involvement with the RadCom 'Antennas' column.

I have been using the 3M bridge with HF antennas for over 35 years after 
reading about it in June QST 1966. It can be quite accurate and able to 
measure the changes in the reactive component of impedance of a test 
resistor with different lead lengths. So simple to - I couldn't 
understand why it didn't catch on.
Not affected by big signals on the band either.

As regards 500kHz activity I recall that it was many months after NOVs 
were issued for 73kHz that we heard anyone at all.

Peter, G3LDO


Dave Sergeant wrote:
> An extensive review also appears in August QST. Nice box, but at $499 
> a lot of money even at the current exchange rates unless you have 
> another application than the MF bands.
>
> Rather less convenient but far cheaper is Peter's 3M bridge. I 
> adapted this and improved its accuracy and found it a perfectly 
> adequate method of matching my antenna. I have a detailed description 
> on my website 500kHz pages.
>
> But it is probably academic now. With yet another station giving up 
> the band last night because of a drop in activity and other reasons I 
> feel things have past their peak. (G3XAQ, G3XIZ, G3VTT and possibly 
> others have now gone QRT). Unless new stations come on the band for 
> proper QSOs I shall do likewise and not waste my time (which is a 
> pity as I am giving a talk about the band at my local club on 
> Wednesday...).
>
> 73 Dave G3YMC
>
> http://www.davesergeant.com
>
>
>
>
>