[Lowfer] Re: Your un-tuned loop

[n8tl]

George:

Thanks for your loop comments....much appreciated.  I basically do the same 
thing only I'm not using a preamp of any
kind.  The R75 preamp is available if needed, however, in most cases, it is 
not required.

Best regards,

Tom N8TL

----- Original Message ----- 
From: "gboorerzl3pn" <gboorerzl3pn at xtra.co.nz>
To: "Discussion of the Lowfer (US, European, &amp; UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Friday, February 01, 2008 3:24 PM
Subject: Re: [Lowfer] Re: Your un-tuned loop


> 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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>>
>
>
> _______________________________________________
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