[Elecraft] K3 on AM with AL811H amplifier

[Joe Subich, W4TV]

> However, according to Ameritron and Tom, W8JI (designer of 
> the AL-80B), 1000 watts PEP on SSB is the upper limit as is 
> 800 watts on CW. 

I don't normally disagree with Tom, W8JI.  However, Eimac's 
data sheets on the 3-500Z - both the 1968 version and the 
current (1980) version - rate the PEP Output Power of a single 
tube in AB2 at 750 Watts.  The 1980 version includes a set of 
at 3500V on the plate that pushes the output to 900 Watts 
PEP - NOT 1KW.

> The key to minimizing non-linearity is to 
> tune with drive set to produce the maximum PEP that will be 
> produced by the transmitted envelope and then slightly 
> "over-tune" (less capacitance) the load control.

And that's not something that one can do when trying to drive 
the AL-80B/K3 combination to 400 W carrier/1600W PEP output. 

73, 

   ... Joe, W4TV 
    





> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Chuck - AE4CW
> Sent: Sunday, February 21, 2010 5:30 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3 on AM with AL811H amplifier
> 
> 
> 
> Joe,
> 
> You are quite correct about limiting AM carrier power on the 
> K3 to 25 watts and AL-80B carrier power to 200 watts.  
> However, according to Ameritron and Tom, W8JI (designer of 
> the AL-80B), 1000 watts PEP on SSB is the upper limit as is 
> 800 watts on CW.  The key to minimizing non-linearity is to 
> tune with drive set to produce the maximum PEP that will be 
> produced by the transmitted envelope and then slightly 
> "over-tune" (less capacitance) the load control.
> 
> Chuck, AE4CW
> 
> 
> 
> > Don´t know how much the AL80B can handle
> > but 1600W PEP sounds to be too much.
> 
> The AL-80B is a single 3-500Z.  It is capable of 800W peak if 
> it is to remain clean and should not be run at more than 500 W 
> CW.  40W carrier from the K3 and 400W carrier from the AL-80B 
> are, in both cases, grossly out of spec. 
> 
> The K3 should not be run at more than 25W of carrier (28W absolute 
> max) and the AL-80B (or any single 3-500Z) should not be pushed to 
> more than 200W carrier (absolute maximum).  
> 
> 73, 
> 
>    ... Joe, W4TV 
>   
> 
> -- 
> View this message in context: 
> http://n2.nabble.com/K3-on-AM-with-AL811H-amplifier-tp4605487p
4609071.html
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