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G0FTD > HELP 05.04.07 18:30l 43 Lines 1209 Bytes #999 (0) @ WW
BID : 000444094PZT
Read: GUEST
Subj: re: half wave end fed
Path: DB0FHN<DB0FOR<DB0MRW<DK0WUE<7M3TJZ<ON0AR<GB7SYP<GB7PZT
Sent: 070405/1522Z @:GB7PZT.#24.GBR.EU [Kidderminster] #:44400 XSERV410h
Date: Thu, 05 Apr 2007 16:22:15 +0000
From: g0ftd@gb7pzt.#24.gbr.eu (Andy)
To: help@ww
Subject: re: half wave end fed
GM7HUD wrote:-
> Andy G0FTD wrote:
>>For 20m, you could always make the matching unit using an air core coil plus
>
> Can you give some more details on the coil then?
It was a simple L-match, from memory about 15 turns wound on a 35mm
film canister and a postage stamp trimmer plus 10m wire for 14Mhz.
It helps if an "antenna analyser" is available, it saves so much time.
With my Palstar I just let it scan for min SWR (only takes a few seconds)
and adjust the inductance to suit until I get there.
I've just found my 20m auto transformer unit, alas it has nothing attached
to it so I can't be certain of the configuration, but it looks like this:
Total 15 turns on 32mm air core 18 swg with tap at 3 turns
|^^^^|^^^^^^^^|
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A B C
I think it went AB for the input (tap at 3 turns) and C to 11m of wire.
"A" being the earthy end.
Perhaps I'll play with it again at the weekend to confirm the config.
> Time for the silly question... Perhaps I've missed this bit, but do you
> need a counterpoise or earth connection?
No.
- Andy -
G0FTD @ GB7PZT
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