[Amps] AL-1200 Tuning Capacitor Range

[Kim Elmore]

Thanks, Carl! The tuning capacitor was *completely* unmeshed and I could 
not find the expected "double dip" points, which is what concerned me. I 
could never know if I was truly resonant or merely close.

I found a way to get the cover off without removing the amp and allowing 
me to spread the 15 m turns a bit.  After spreading the 15 m part of the 
coil, everything is precisely as I like it. I get full steam out on 15 m 
(with ~105 w of drive) and, as expected, run out of drive on 10 m. If I 
could drive it hard enough, I'm pretty sure I'd get 1500 W out before I 
hit the plate or grid current limits. All this with 4 kV on the plate, 
along with the necessary an added capacitor in the HV PS for the extra 
voltage and a bit more bias voltage on the grid to set the proper idle 
current.

The AL-1200 is nowhere near an Alpha (and far from anything with a 
3CX3000A7 in it), but I got it for an excellent deal. I added a QSK-5 
internal QSK switch, and replaced all the filter capacitors and bleeder 
resistors so my bang-for-the-buck is superb.

Kim N5OP

On 10/18/2014 10:59 AM, Carl wrote:
> If the tank is resonating at "almost" unmeshed and there are two 
> resonance points as you continue the rotation youre fine, leave it alone.
>
> Carl
> KM1H