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Re: LF: 8.97kc - TV transformer info needed

To: [email protected]
Subject: Re: LF: 8.97kc - TV transformer info needed
From: Stefan Schäfer <[email protected]>
Date: Mon, 31 May 2010 16:53:34 +0200
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Mike,

Try to use just 65 % of the turns of your primary winding and i bet the optimum will be on 9 kHz! :-)

73, Stefan


Am 31.05.2010 05:03, schrieb Mike.WE0H:
Well worth testing. There might be some other transformers that work and we won't know which ones until someone tests them. Looks like 4kc is the peak of efficiency on that transformer you tested. I found 5.8kc is the best efficiency on my TV transformer.

Mike
WE0H




John B wrote:
Hi Mike, LFers,

I grabbed one of my many MOTs and ran some tests with the primary connected to a signal generator's 600 ohm output and the secondary connected to a VTVM. The measured L of the primary is .047 H and the secondary L is
16 H.  The turns ratio (120 Volt Primary) is 1:18 give or take a bit.

With the signal generator set at 10 volts RMS, the secondary voltage was measured at 1 kHz. steps as below:

Freq. in kHz.   Sec. voltage

          1                     120
          2                     150
          3                     190
          4                      250
          5                      210
          6                      160
          7                      140
          8                      110
          9                        85
         10                       60

The results are poor, just as you found Mike, so it looks like we can rule out using MOTs for Dreamers Band. It's about what one might expect from a transformer designed for 60 Hz. operation.

73, J.B., VE3EAR

LowFER Beacon "EAR"
188.830 kHz. QRSS30


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