1KW input on CW, 2KW PEP on SSB was the FCC reg back then. For that reason
many amps of that era had a CW/SSB plate voltage switch. Many left it in the
SSB position irregardless of the mode (; No sense in throwing away 3dB in a
pileup.
Carl
KM1H
----- Original Message -----
From: <Gudguyham@aol.com>
To: <garyschafer@comcast.net>; <amps@contesting.com>
Sent: Monday, July 23, 2007 12:33 PM
Subject: Re: [Amps] Drake amplifier
>
> In a message dated 7/23/2007 12:21:44 P.M. Eastern Daylight Time,
> garyschafer@comcast.net writes:
>
> I have a drake L7 amp.
> How much power out do you typically get from a drake L4 or L7 amp? I have
> 95
> watts drive and get just short of 1100 watts on 40 meters.
>
> The amp's wattmeter and a bird wattmeter with a brand new slug agree
> almost
> exactly.
>
> This seems a little low or is that about all that can be expected from
> the
> 3-500Z's. They run at 2450 volts on the plates and 230 ma grid current.
>
> Thanks
> Gary K4FMX
>
>
>
>
>
> Hi Gary, Yup, that is about right 110-1200 watts out with around 100 watts
> of drive. If you have a look at an AL-82, it will do about 1600 watts out
> with 100 watts in. The difference is in the fact that the Ameritron AL-82
> runs
> the anode at about 3600-3700 volts. The extra plate voltage really makes
> the
> 3-500Z's play great. The "HOT" set up for the Drake L4 or L7 would be to
> build up a better HV supply. The Drake tank circuit can take 4KV no
> problem.
> But what you are seeing now is right on the money. You have to remember
> that
> when the L4/L7 were made, the maximum power permissible by the FCC was
> ONE
> KILOWATT DC INPUT. That being so, the amp companies did not run a pair
> of
> 3-500's to their full potential so they got by with wimpy power supplies.
> Put a
> good power supply on an L4 and it will perform nicely. Easy legal limit
> amp
> plus. Oddly, the Drake RF deck makes a great conversion to an 8877 and
> handles the 2KW easily.
> 73 Lou
>
>
>
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