Topband: k9ay Loop relay box?

[Daniel Hileman]

 Hi Everyone,
 
Thanks for the Great input! I'm gonna give the FAR circuit a try! 
 
Thanks and 73,
Dan N9WX
 
 
 

> From: g3pqa at onetel.com
> To: n9wx at hotmail.com
> Subject: Re: Topband: k9ay Loop relay box?
> Date: Wed, 15 Feb 2012 11:03:40 +0000
> 
> Hi Dan,
> 
> Not too difficult construction or critical components. Switched 12 (or 24) 
> volt psu, and virtually any two double change-over (12 or 24v) relays in the 
> remote box, with their associated matching transformer, chokes, capacitors 
> etc..
> http://www.hard-core-dx.com/nordicdx/antenna/loop/k9ay/k9ay_orig.pdf
> The small 12v mains transformer cost approx $1.50 and the relays 1$ each. A 
> few capacitors and 100uH chokes. Most of this you should be able to pick up 
> at a hamfest.
> I built one for a friend, using Gary's original article, similar to link 
> above. Photos attached, you can zoom up and see exactly how it is wired. 
> (sorry, not my prettiest construction).
> The only major difference from Gary's circuit was that, if I remember 
> correctly, I used a binocular ferrite (1:9 for 50 ohm coax, 1:6 for 75 ohm 
> coax) matching transformer in the remote box rather than an autotransformer 
> to reduce any possible common-mode feeder pickup, but this was not strictly 
> necessary. I could have simply wound 20 or so turns of thin coax in a 
> FT240-31 and patched it into his feeder close to the box which also would 
> have blocked any common-mode.
> 
> Also I have built the Far-Circuits kit, which is two pcbs including a 
> W7IUV-type preamp and 160m hpf for rejecting BC birdies, but never completed 
> it because it still needs mounting in the boxes and home-brew psu switching, 
> and seemed over complicated for the purpose (the switching design and kit 
> was not included with mine). I think it works OK though, particularly if you 
> need the extra gain, perhaps others who have it working will advise you. 
> Usually, extra preamplification at a K9AY is not needed on 160m.. The other 
> difference between this kit and Gary's original design is that Gary's just 
> power-feeds the switching voltages down the coax centre, whereas the 
> Far-Circuits design uses a multicore cable.
> 
> Good luck with the project.
> 
> 73's
> John G3PQA
> 
> -----Original Message----- 
> From: Daniel Hileman
> Sent: Wednesday, February 15, 2012 12:38 AM
> To: topband at contesting.com
> Subject: Topband: k9ay Loop relay box?
> 
> 
> Hi...I am interested in building a set of K9AY Loops, but those relay boxes 
> are expensive to BUY! Anyone know of source of a kit? Or, anyone in the 
> Dallas area want to get together and help a newbie to building circuits, etc 
> build one?
> 
> Thanks and 73,
> Dan N9WX
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