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From: "J. Allen" <vy1ja@northwestel.net>
To: "LF \(RSGB\)" <rsgb_lf_group@blacksheep.org>,
	<lowfer@lwca.org>
Date: Sun, 9 Jul 2006 04:00:40 -0000
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Subject: LF: transformer question
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Status: O

Alan and All,

Alan, you were concerned about the transformer that was added between the 
coax and the loading coil at the base of the 137 kHz. antenna.  Here 
follow-up to your question.

If you remember it is a bifilar winding of ten turns which takes up on inch 
length on a 10-3/4 inch form.

I used Solenoid3 which may or may not be the right tool for the job, and 
calculate the self-impedance of the windings to be just about 50 Ohms at 
137.8 kHz. I do not know if 50 Ohms is good, bad or what.  Can anyone tell 
me?

I am concerned that the 50 Ohms of self impedance might be giving me a false 
OK on my system and that I actually still have antenna problems even though 
the system radiates and looks matched.

Even in the bad conditions yesterday, some bits of the transmission have 
appeared on Scott's screen 1000 Miles distant, and we are trying it again 
tonight.

The transformer was wound by guess, since I cannot remember if I have seen 
any data on properly wining a solenoid type transformer with bifilar 
winding.

Anyone know the answer or have a link to the information on winding these?

J.