[CQ-Contest] Amp questions

[Bob Wolbert]

On Sun, 4 Jan 1998 11:17:53 EST TOMK5RC <TOMK5RC at aol.com> writes:
>Need a couple of quick answers about amps and the "amplifier" 
>reflector has
>been non-responsive.
>
>Ameritron AL1200 - What is the Manufacturer's not-to-exceed grid 
>current? What
>is typical grid with 1500 watts out?
>

The manual says 250mA on the meter. The tube mfg rates grid diss at <50W.
I believe this manual is available on-line at Ameritron or MFJ's web
site.

Typical grid current at 1.5kW? "None"
Why--1. Amp works better at lower freqs-about 220mA/1.5kW on 80/40/20m.
About 250mA at 15m. Cannot get 1.5kW on 10m, even with >160W of drive.
Manual rates maximum drive at 120W.

Evidently there is very wide variation among AL1200s. Mine is quite
different from QST review, and a bit different from its manual(!). I
guess that's what we call "MFJ Quality" [sic].

AL-1200 is a decent value at $1700, IMHO. I got mine used for $1000 in
nearly perfect shape. Got a semi-used spare tube for $400. New tubes are
$650 from RF Parts, I think--not sure though. 

However, my AL1200 is now amp #2 to my new Alpha, because of the high
drive and low 10m output power issues. There is a HUGE difference between
the two in terms of quality and operating ease. 

In fairness, the AL-1200 has one advantage to a casual operator/DXer: it
is ON and ready in ten seconds, while the other takes 2.5min--but I'm
sure you already know that, Tom, and it doesn't relate to normal contest
operation.

73, HNY & GL de Bob, K6XX


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