One or two "flat" roller inductor coils, in the form of a concentrical
spiral made with a silver plated copper belt, were a common solution in
medium power (up to 10 Kw) 2-30 Mhz HF commercial amplifiers (Collins &
others).
A 20 uh fixed, home made version of this coil type, moreover for a 160m use,
hasn't big requirements than a reasonable space in two dimensions and do not
has a potentially saturable core to deal with.
73,
Mauri I4JMY
----- Original Message -----
From: Radio WC6W <wc6w@juno.com>
To: <amps@contesting.com>
Sent: Tuesday, January 25, 2000 7:10 AM
Subject: [AMPS] Smallest practical 1.5KW 20uH coil
> I'm now considering a short solenoid cross section wound in the form of
> two adjacent spirals (one spiraling into the center, the other out)
> fabricated from .375 by .07 silver plated copper ribbon. Sixteen turns,
> 8 in each spiral, in a 3" diameter by just under 1" thick form factor
> should provide the requisite inductance. I'll just slip some thin strips
> of fiberglass between the turns to keep them properly spaced. The only
> drawback that I perceive in employing this geometry is the somewhat
> higher than usual inter-turn capacitance but, this part is only for use
> on 160M.
>
> Comments, suggestions, alternative ideas??? but, please no
> superconductors! :-)
>
> 73,
> Marv WC6W
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