Lee the 77 will work just fine on 17 meters. Put the bandswitch in the 15
Meter postition and use your transceiver's antenna tuner to improve the
match. The input tuning on the 77 is fairly broad but you'll see more
output with a better match.
You'll find that the settings for 17 will be very similar to the 20 meter
Load and Tune settings.
The situation on 12 Meters is a little different. The manual warns you
against operation in the vicinity of 25 mHz. This is because the plate choke
is series resonant in that region. Actually the two-tube versions come
closer to working than the single tube version. The fix is to switch out
the lower third of the choke on 40 meters and above, moving the resonance
above 30 mHz. This is a trick ETO (Alpha Power) utilizes on the newer rigs.
It's a fairly extensive upgrade just to make it work well on 12 meters. I
have modified two two-tube rigs for 12 meter operation but really I don't
want to do it again...just too much work.
I'm experimenting with a plate choke I bought at Radio Kit. That's whats in
my two-holer right now and when 12 meters actually opens up a bit, I'll be
more prepared to give an evaluation of that attempt.
If you really want to give it try, go to the 10 Meter position and see what
you can get out of it. Even 600 watts would be helpful. Just keep an eye
on the grid current as the tuning is rather sharp.
How about answering a question for me? I'm using Eudora Light as my mail
program. When responding on this forum is it best to 'forward';
're-direct'; 'reply' or what?
I like including the senders' comments along with mine.
73, Dick
>From: Lee Roger Wical <leewical@lava.net> (by way of Richard Byrd
<n4uq@mindspring.com>)
>Subject: [AMPS] ALPHA 77SX/77DX
>
>Gentlemen:
> I have a Alpha 77SX bequethed (sic) to me.
> My question has anyone place this amp on the WARC bands for 12 & 17 Mtrs?
> What does it take to get it working there?
> Lee
>Lee Wical
>
>
>
>
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