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From: "Ashlock,William" <William.Ashlock@edwards.boc.com>
To: rsgb_lf_group@blacksheep.org
Date: Tue, 8 Oct 2002 16:33:07 -0400
MIME-Version: 1.0
Subject: LF: RE: Re: RE: Lasso alias loop
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Reply-To: rsgb_lf_group@blacksheep.org

Mal,

> My loop uses the same wire as the vertical antenna and radials. I use
multi strand 2.5 mm insulated  
> electrical  wire.  
 
OK, that's the same as US AWG #10 which is about 15% lower in Rac per foot
compared to Mike's #12, when some ground loss is figured in. 
 
>The loop is vertical and the top wire is up abt 70 ft and its natural
resonant freq is 90 metres. 
 
That would make the perimeter about 1.5 times larger than our loops, which
is good. The Rac total would be about 1.5 ohms. You will need a 6 to 1
transformer able to handle your power level installed at the feedpoint of
the loop. What are you using for this? BTW, on Receive the transformer
increases the signal by 6X . 
 
You also need a resonant capacitor bank in series with the loop and
secondary of the transformer of about 7000pf and able to withstand your
power level. This would mean many kv and many amps. What are your using for
this? 
 
What I think you are doing, based on the impression I got when you set up
this loop earlier in the year, is that you have left out the transformer and
the resonant capacitor bank and are trying to achieve the matching back in
the shack. Not surprising because these are difficult components to obtain
in the 1kw power range. What makes the US lowfer band so easy (and fun) is
the transformer can be as simple as 6 turns on a 1/2" ferrite core and a
500v dipped mica can be used as the resonant capacitor.
 
IF this is the case, would you please do the following for me and the rest
of the loop enthusiasts? :  Install the transformer and resonant capacitor
bank  - able to handle a power level that is not too difficult to achieve,
say 50 -100W. Reduce your transmitter's power to this level and make A/B
comparisons between your vertical and the loop, with contacts in the general
direction to which your loop is pointed. I bet my bottom dollar that you
will be impressed with the results! 
 
Best regards,
Bill A

 
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