>
> -----Original Message-----
> From: Amps <amps-bounces@contesting.com> On Behalf Of Joe
> Sent: Monday, September 13, 2021 12:36 PM
> To: Amps Reflector <amps@contesting.com>
> Subject: [Amps] Amp With A Roller Inductor?
>
> Here's a Question,
>
> Been hitting a dead end. I have had various AMPs all my Ham life, from 1975.
> But all have been like the SB-220,
>
> SB-220,
> SB-200
> FL-2100,
> Henry 2K
>
> etc.
>
> Plate cap, load cap, tapped inductor.
> and old school tube rigs Drakes mostly.
>
> So very familiar with tuning it up.
>
> Now I have been You Tubing, with zero results.
>
> And just plain old Googleing,,,, and all I get are results about antenna
> tuners.
>
> how to tune an amplifier with a roller inductor?
>
> I can not find an answer to that question anywhere.
>
> How does one tune an amp that uses instead of a tapped inductor, but uses a
> roller one?
>
> Joe WB9SBD
> _______________________________________________
You do the math or measure the coil’s inductance and per the plate load
impedance, pick your “taps”.
You will be using a turns counter dial. Write down the numbers for each band.
Chart on panel.
Do tune and load, as before. You don’t need to move the coil for tune-up.
It is nice to tweak the coil under power and do a little better than the text
book
It does give the versatility of running any lower power level.
If you don’t want full 1500, run 1000 and do a new chart with different Pl z.
I’ve seen a couple home-brews with motor drives and digital readouts or auto
control.
My 1980’s 3-500’s still works fine.
Charts are in the handbooks.
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