Where did you get the idea that an 8877 can "deliver safety only 1500W?"
It's a 1500W rated _dissipation_ triode. Normally, one can achieve about 2x
the plate dissipation rating of any transmitting tube operating in linear
ICAS. 8877's are used in broadcast service in the FM band at 2000W carrier
power output, continuously, albeit with larger power supplies and cooling
systems than you'll find in amateur amplifiers, and running Class C.
3CX800's and 4CX800's, having only 53% of the dissipation rating of the
8877, are commonly found and on the market running full amateur legal limit
output power.
The internal cooling system in the AL1500 appears fine for > legal limit
power, as the only thing getting hot during my testing was my Bird dummy
load. The amp exhaust air stream gets quite warm, as would be expected, but
does not seem overly hot. I have a number of external anode (finned cooler)
amplifiers using 8874's, 4CX250's, 8122's, etc, and the AL1500 exhaust air
is certainly no warmer than any of those (from Alpha/ETO, et al).
If you're skeptical, I'd recommend you go with something else. But I've had
no problems with the Ameritron products from the AL80B to the AL1500 (and
including the AL1200)...although admittedly haven't used the little ones
like the AL811, etc.
73
WB2WIK/6
"Each success only buys an admission ticket to a more difficult problem." --
Henry Kissinger
> -----Original Message-----
> From: alex [SMTP:alex@sandlabs.com]
> Sent: Monday, December 03, 2001 4:32 AM
> To: Steve Katz; amps@contesting.com
> Subject: Re: [AMPS] AL1500
>
> This is interesting... The tube, I understand, can deliver safely only
> 1500W.
> How do you get so much more... And how about cooling... Is the internal
> blower enough at these power levels ?
>
> Alex, N2NNU
>
>
>
>
> ----- Original Message -----
> From: "Steve Katz" <stevek@jmr.com>
> To: "'alex'" <alex@sandlabs.com>; <amps@contesting.com>
> Sent: Monday, December 03, 2001 4:42 PM
> Subject: RE: [AMPS] AL1500
>
>
> >
> > Is that a French ham or a Function key? <yuck>
> >
> >
> > > A friend of mine, an F3... , (has no internet access) wants to know:
> > >
> > > Does anyone know what the AL1500 is _really_ capable and under what
> > > conditions?
> > [Steve Katz] The AL1500 runs a lot of power. Not so much for
> > people using "tetrodes with handles," but more than the amateur legal
> limit,
> > for sure. Had one on the bench churning 2200W carrier power for (yawn)
> > about ten minutes before I decided that was enough garage heating for
> the
> > day. Besides, my Bird 1200W load was getting rather toasty. I don't
> doubt
> > for a moment that it can run 1500W output continuously (not necessarily
> in
> > the broadcast sense, but in the amateur sense).
> >
> > WB2WIK/6
> >
> >
> > > I have no experience with it, so perhaps somebody in the group could
> help
> > > him.
> > > TIA, Alex
> > > N2NNU
> > >
> > >
> > >
> > >
> > > --
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> >
> > --
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> >
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