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From: "J. Allen" <vy1ja@northwestel.net>
To: "LF \(RSGB\)" <rsgb_lf_group@blacksheep.org>
Date: Fri, 7 Jul 2006 22:53:40 -0000
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Subject: LF: Need Solenoid transformer data for antenna
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Status: O

I am starting to see progress but now, every time I get close to resonance, 
the waveform of the voltage becomes quite distorted.  I believe that it was 
Scott who told me that the way he beat the waveform problem was to use an 
isolating transformer at the antenna.

I have no iron but I have a LOT of different sizes of PVC conduit and wire. 
What I propose is to take a piece of that 10-3/4 inch form and wind a 
trifilar of #17? on it.  One winding would be for 50 ohms primary from the 
transmitter and the other two would be secondaries.  I can tap one of the 
secondaries for antenna impedances less than 50 and if needed add the second 
winding in series for impedances above 50.

The problem is that I do not have any idea how many turns I should have.  I 
think too few will result in poor coupling and too many may cause the 
internal reactance to limit current flow.

Any guesses where to start?  The wire works out to about 19 turns per inch, 
so dividing by 3 means 19/3 or 6-1/3 turns per inch on all windings.

To get started, I plan to make about 8 trifilar turns of each.  If this is 
poor design, please let me know.

I tried a transformer made over a TV horizontal output core and when I 
applied this to the dummy load, the current was lagging the voltage with 
only about 24 turns on it.  I do not like the result and set the idea of 
iron out of the way for now.

"J"