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Re: [Amps] AL-1200 on AM

To: "Daniel Hileman" <n9wx@hotmail.com>
Subject: Re: [Amps] AL-1200 on AM
From: rich <r@somis.org>
Date: Sun, 30 Oct 2005 08:04:04 -0800
List-post: <mailto:amps@contesting.com>
On Oct 30, 2005, at 6:02 AM, Daniel Hileman wrote:


> Hi Everyone,
>
> I am thinking of buying an AL-1200 (as opposed to the 1500, because  
> of the
> 3cx1200's great track record)
>

The 3cx1200A7 has more feedback C than a 3-500Z, so much so that  
Eimac redesigned it.  Of course, for those interested in building a  
VHF VFO the A7 is ideal.  The redesigned, improved version is the  
3cx1200Z7.  However, a Z7 is not even close to being interchangeable  
with an A7.
.  As to the AL-1500, it can be made more stable by adding a low VHF- 
Q parasite suppressor at the anode, however, this will reduce the  
output on 10m by a couple of %.   Also, if one is present, removing  
the so-called "neutralization" circuitry improves stability.


> and am getting interested in AM operation, I
> have Kenwood TS-850s which is supposed to be GREAT on AM.  One of  
> these
> days, I will get a nice Big Boat anchor..but for now the 850 will  
> have to
> do. My question is, how much carrier can I safely get out of the  
> 1200?? I
> figure my 25 watt carrier from the 850 will NOT drive the amp hard  
> on AM,
> but just curious.
>

100w PEP will overdrive a 3cx12007 or an 8877, but it will under- 
drive a pair of 3-500Zs.  To increase the output of a TS-850S,  
operate it at the rated max of 16VDC and adj. the internal ALC  
control for what u need.  I have been operating my 850 from 16V for  
over a year without a problem.  With 16V in an 850 should be capable  
of 150W out.


> If I had the ability to drive the amp on AM, what would be
> a safe carrier limit out of the amp?
>

80W drives a 3cx1200A7 to full throttle, so an AL-1200 amplifier  
should be tuned up for max out with a keyer sending 80w dits at  
50wpm.  Next, adj. the carrier to 20W and you're ready to make a 10- 
minute lock-to-talk transmission on very wonderful A.M..

end

>
> Thanks for all your input,
>
> 73,
>
> Daniel N9WX
>
>
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