[Amps] AL1200, RTTY contesting, temps, duty cycles (not 100%)

[Jeff Blaine AC0C]

Thanks for the catch, Bill.

My point (which I was not clear about) was to outline the relationship 
between the variables and the plate dissipation.  So the guy can do his own 
calculation.

I really don't recall the operating parameters of the 3500z other than 2KV 
is pretty low - I think the old SB220 ran about 3KV+ in the SSB position - 
that matches up with your numbers below.  I should have been more explicit.

73/jeff/ac0c

--------------------------------------------------
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
Sent: Sunday, July 05, 2009 11:03 AM
To: "Amps reflector" <amps at contesting.com>
Subject: Re: [Amps] AL1200, RTTY contesting, temps, duty cycles (not 100%)

> ORIGINAL MESSAGE:
>
> On Sun, 5 Jul 2009 09:03:15 +0800, "Jeff Blaine AC0C" 
> <keepwalking188 at yahoo.com>
> wrote:
>
>>
>>If I'm not missing my guess, I think you would only approach the tube 
>>plate
>>disipation limit at up to something like 1100 ma of plate current and
>>perhaps 100w drive.  Assuming the same overall efficiency, that would be
>>around 1200w out and a bit over 1KW of plate dis.  I'm assuming the B+ 
>>line
>>would drop slightly off the 2KV level.  The 3500z is a pretty tough 
>>beast -
>>if you can keep it's feet cool.
>
> REPLY:
>
> The 3-500Z cathode current limit is 400 Ma or 800 mA for two tubes. The 
> 3-500Z
> will work at 2 kV on the plate but it is happier with more. At 3 kV and 
> 800 ma
> you have 2400 watts DC input and with a decent tank circuit, should get 
> 1500
> watts out or very close to it. Also, at 3 kV on the plate, it can be run 
> "zero
> bias" which means you don't need a zener in the filament circuit.
>
> 73, Bill W6WRT
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