[Amps] AL-80A tube glow

[jeremy-ca]

Id say thats pushing the 3-500Z a bit too much. Drop the drive down to 
60-70W and the grid current to 125-150ma and the tube will thank you by 
working much longer. At 600-700W the difference at the other end is nil.

Carl
KM1H



----- Original Message ----- 
From: "Kim Östman" <kim.ostman at tut.fi>
To: <amps at contesting.com>
Sent: Saturday, July 07, 2007 3:09 AM
Subject: [Amps] AL-80A tube glow


> Howdy,
>
> I've been using the AL-80A successfully (apart from some rare arcing
> inside) for about 10 years off and on, including contests.
>
> Something that I've paid notice to only as of late in the 3-500Z tube
> is a gradually increasing orange or light red colored glow in the
> metallic cooler wings(?) as one sends CW of SSB during an "over". Is
> it normal for the tube to begin glowing like that, or is something
> wrong?
>
> The SWRs on my antennas are below 2:1, tube plate current around
> 450-500 mA (which I guess is stretching it a bit), and grid current
> around 200 mA. Output according to a Daiwa meter is between 700 to
> 1000 watts depending on the band.
>
> Thanks in advance!
>
> 73 / Kim OH6KZP
>
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