[Elecraft] 100 Watts or 500 Watts

[Vic K2VCO]

I just finished building a grid-driven amplifier using two 813 tubes. With a 3 db 
attenuator at the input, it requires between 16 and 40 watts of drive on 160 through 10 
meters respectively, for 800 watts output (only 700 on 10). Without the attenuator, it 
would need 8 - 20 watts drive.

And this is a class-C amplifier designed for CW only! If it were a class B or AB linear, 
the drive requirement would be even lower.

Grounded-grid is not the only way to design a tube amplifier. Although a traditional 
grid-driven circuit is a little more complicated, it's one way to get more gain.

I am going to put some pictures and schematics on my web site soon, not that I think 
anyone will want to duplicate it!

On 12/22/2010 7:50 AM, Ron D'Eau Claire wrote:
> Even the Elecraft 100 watt amps are integrated with either the K2 or K3
> control logic so they cannot be used as a stand-alone amplifier with other
> transmitters.
>
> The only reason I have ever seen from the FCC for the amplifier
> certification and 15 dB gain limitation is to discourage the CB
> 'bootleggers'. Certainly building a stable, clean amplifier that would take
> even a few milliwatts to 1000+ watts is a straightforward design exercise.
> There's no real problem with using more than one stage of gain if there was
> no 15 dB limit on the system gain.
>
> Ron AC7AC

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/