[Lowfer] Re: Your un-tuned loop

[gboorerzl3pn]

re untuned loops lf use..down here in  ZL  some   hams  use single turn loop 
for  recieving  coupled directly in to high gain low impedance 
transistor...no reactance correction etc is needed ...not for transmitting 
of course....very broad for recieving...i like to resonate my loops    ..73s 
george  zl3pn
----- Original Message ----- 
From: "J. B. Weazle McCreath" <weazle at hurontel.on.ca>
To: "Discussion of the Lowfer (US, European, &amp; UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Saturday, February 02, 2008 2:19 AM
Subject: Re: [Lowfer] Re: Your un-tuned loop


> Hi Tom, Lowfers,
>
> I thought you might be interested in the alternate feed
> arrangement that I'm currently trying on my big delta
> loop for 500 kHz.  I had been using series tuning and
> a 4:1 turns ratio step-up transformer to couple to the
> RG-6U feedline.  It works fine on the frequency that
> it was tuned to but left a lot to be desired if I moved
> away from that frequency.  I want to do some NDB
> work and hence need a broadband antenna/coupling
> arrangement.
>
> I measured the loop's inductance to be 200 uH. and then
> calculated the inductive reactance over the frequency
> range that I wanted to cover.  The calculations showed
> that a 2:1 turns ratio step-down transformer would give
> a reasonable match to the feedline.  I wound one using
> a binocular core with 16 turns on the antenna side and
> 8 on the feedline side.  It's reactance is much larger
> than the antenna's or feedline's.
>
> This seems to work pretty well, at least in the time I
> have been testing so far, but the lack of selectivity
> does show up.  I'm thinking of trying out an in-shack
> tuning setup similar to M0BMU's "lazy loop", but will
> my matching transformer give me trouble?  In essence
> I'd be doing the tuning on the feedline side rather
> than the antenna side.  Any comments are welcome.
>
> 73, J.B., VE3EAR - VE3WZL
> Solar and wind powered
> Lowfer " EAR"  188.830
> EN93dr
>
> http://www.hurontel.on.ca/~weazle
>
>
>
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