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From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <007701c6a218$306fb5a0$6501a8c0@eagles>
Date: Sat, 8 Jul 2006 00:07:42 +0100
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Subject: LF: Re: Need Solenoid transformer data for antenna
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I am afraid that suggests to me that you are not resonating the aerial at
the expected frequency. A high Q tuned circuit should make the sinewave
better not worse !! If you start putting transformers in you are going round
the old loop again where you are not quite sure whether you are measuring
the antenna or the transformer. My feeling is that you do need to get it
properly resonant first.

Could it just be that if your drive source has harmonic content and you are
using a series resonant method that someone suggested.......the poor
waveform is a good sign !! it means that you have the main resonance and
what you are seeing is the hamonic content of the generator  This is the
classic way of measuring harmonic distortion an amps and generators by
nulling the fundamental in a notch filter (more effective than a series
tuned cct)

Cheers de Alan G3NYK

----- Original Message -----
From: J. Allen <vy1ja@northwestel.net>
To: LF (RSGB) <rsgb_lf_group@blacksheep.org>
Sent: 07 July 2006 23:53
Subject: LF: Need Solenoid transformer data for antenna


> 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"
>
>
>