[Lowfer] Re: Your un-tuned loop

[n8tl]

Hi JB:

Yes...that's the reason my loop is untuned....its is then broadband to 
receive other parts of the spectrum, e..g., NDBs,
time broadcasts at 60 khz, 500 khz, etc.

The co-ax is direct coupled at the antenna end. The characteristic impedance 
for the loop at 600 meters is about
19 ohms and drops as you go lower in frequency to about 2.7 ohms at 60 khz. 
So for matching to co-ax impedance
I would need to have variable coupling between 19 and 2.6 to 1.  Since I 
copy most stuff in the frequencies of interest,
I decided not to try and match.  However, if I were coupling an RF exciter 
to the antenna.....then proper matching would be necessary.  I relize that 
the efficiency would be better if the antenna was resonant at each frequency 
with better
signal sensitivity....but, gee whiz,  this system is working okay to copy 
east west signals, and, I don't have to run outside and change an impedance 
tap hi hi.

Best Regards,

Tom N8TL

----- 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: Sunday, January 06, 2008 9:03 AM
Subject: [Lowfer] Re: Your un-tuned loop


> Hi Tom,
>
> How are you coupling the coax feeder to your 150 ft.
> perimeter un-tuned loop?  I have a 333 ft. perimeter
> loop I use for 500 kHz., but it's series tuned and fed
> via a 4:1 step-up transformer.  Maybe I should think
> about making it un-tuned so I can use it for NDBs
> and other LF signals outside "our bands".
>
> 73, J.B., VE3EAR - VE3WZL
> Solar and wind powered
> Lowfer " EAR"  188.830
> EN93dr
>
> http://www.hurontel.on.ca/~weazle
>
>
>
> _______________________________________________
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