[ARC5] ARC-5 antenna match

[Christopher Bowne]

Yes- this is an external circuit.  I made mine up on a small wooden board.  I don't recall the specifics of the coil described in Walt's article (it was in an 1989 or early 90s ER issue), but they probably are not too critical.  I just used what I had  (the old Eico 720 pi-net coil) and it works great.  It circuit looks a little odd in that there is no connection to the "top" of the parallel tuned circuit, the antenna feedline is tapped up about 6 turns from the cold end, and the series fixed 200 pf cap to the transmitter antenna post is tapped in about three turns from the cold end.  Of course, both the coax shield and the transmitter chassis are connected to the cold end.  The Eico coil has about twenty closely spaced turns and a second section with maybe 10 wider spaced turns.

Maybe someone can find the article and post the details, my back issues are buried away too deep to get at them easily!




________________________________
 From: David Stinson <arc5 at ix.netcom.com>
To: arc5 <arc5 at mailman.qth.net> 
Sent: Sunday, July 28, 2013 10:40 AM
Subject: Re: [ARC5] ARC-5 antenna match
 


----- Original Message ----- From: "Christopher Bowne" <aj1g at sbcglobal.net>

> ..... the parallel tuned circuit autotransformer circuit described by Walt >Hutchens, KJ4KV very early on in his ER in Uniform series of articles on the >SCR-274/ARC-5 command sets. It consists of a parallel tuned circuit where >the antenna feed line is tapped on the coil about 5 turns up from the >grounded (cold) end, and the transmitter is fed through a 200 pf series cap to >a tap about 3 turns up from the cold end of the coil. ...

I'm a bit confused.  Do you mean you solder taps on the tank coil
inside the rig, or use an external coil?
If external, what are the specifications of the coil?

73 Dave S.

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