[Amps] Question: Ameritron AL-80A tuning

[peter.chadwick at Zarlink.Com]

What's the input SWR? I'd suspect the input tuned circuits may be so far 
out that you're exciter is shutting down and the amp isn't getting much 
drive.

73

Peter, temporarily  SM/G3RZP





"NW7US, Tomas" <nw7us at hfradio.org> 
Sent by: amps-bounces at contesting.com
2004-12-01 17:46

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"amps at contesting.com" <amps at contesting.com>
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Subject
[Amps] Question: Ameritron AL-80A tuning






Hi,

I am using an AL-80A and have need as an Army MARS and National Guard Net 
member to utilize frequencies far out of normal Amateur Radio 
allocations.  I am finding it hard to get the Amp to tune on certain 
frequencies "out of band" - I can get about 100 watts on those problem 
frequencies.

I suspect that the filter netwoks in this Amp prevent it from being used 
too far out of frequency.  Is that true?

For instance, let's say that I need to be on a frequency close to 5 MHz. 
I cannot get more than about 100 watts out of the amp.  However, if I am 
just above 4 MHz, I can get full power out.  So - it must be a filtering 
issue.  In this case, I am keeping the BAND switch on 80, and the PLATE 
ends up around the 40 section, and LOAD is between 5 and 6.  I have tried 
other positions, and nothing works nearly as well as this - but this 
position only gets about 100 out.

Now - is there a mod for the amp that would allow a wider range to tune??  

Or, do I give up on this amp for MARS usage?

Thanks in advance.

-- 

73 de Tomas, NW7US (AAR0JA/AAA0WA)

: Propagation Editor for CQ, CQ VHF, Popular Communications :
: Creator; live propagation center http://prop.hfradio.org/ :
: Associate Member of Propagation Studies Committee of RSGB :
: US Army Miltary Affiliate Radio Service (MARS) SMD AAA0WA :
: 122.93W 47.67N / Brinnon, Washington USA CN87 CW/SSB/DIGI :
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