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[AMPS] AL-1200

To: <amps@contesting.com>
Subject: [AMPS] AL-1200
From: 2@vc.net (measures)
Date: Thu, 31 Aug 2000 04:55:09 -0700
>
>Just spent quite a bit of time looking over the past 3 years of
>archives on the AL-1200
>
>They indicate:
>1)40/80 RTTY operation at near full power burns up tank circuit
>components

There is not enough copper in the tank.  There is apparently no air 
cooling for the tank.  Both problems can be fixed.  

>2)10 meter efficiency is poor with little chance of getting full
>output.

At best, you might be able to get 2db more suds on 10m/11m by using 
larger tank conductors.  Could anybody really tell the difference?  
Doubtful. 

>3)Parasitic oscillation problems haven't been solved

The good news is that 3cx1200A7s almost never have filament/grid shorts.  
The 3CX1200Z7 is a more stable design since it has approx. 10% as much 
feedback C.  MFJ has not switched to the improved version.  Is Martin F. 
Jue clueless?  

>4)Noise from fan intolerably loud
>5)WARC bands are a compromise because of tuned input circuitry. One
>has to mistune it to  get both WARC and adjacient non-WARC bands.
>
>Is this info still valid?  

You forgot the prob. with the 1000pF HV ''bypass''.  -88-ohms of Xc is 
assuredly not a ''bypass''.  

>If it is, it says manufacturer's apparently
>never test their
>products.  I don't understand why anybody would buy this unit.
>
>There doesn't appear to be any currently made amp out there that is
>instant on, quiet, stable, WARC band friendly with 1.5CCS output
>
>Brian/K3KO
>
? 1500w out CCS requires a 2500w CCS supply.  The Henry 3K-A is the only 
game in town.  However, the VHF stability needs improving,  it needs 
glitch protection, and it needs high speed switching.  

cheers


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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