[Amps] Amp With A Roller Inductor?

[RCM]

> 
> -----Original Message-----
> From: Amps <amps-bounces at contesting.com> On Behalf Of Joe
> Sent: Monday, September 13, 2021 12:36 PM
> To: Amps Reflector <amps at 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.