When I think about it, the H-1000 was probably only rated to 25 MHz....
Actually their uses as I witnessed them were most for NVIS
and as a component in very early frequency-hoppers.
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: <G3rzp@aol.com>
To: <sm0aom@telia.com>; <avilaseca@bluewin.ch>; <wa1hco@adelphia.net>
Cc: <amps@contesting.com>
Sent: Wednesday, December 29, 2004 11:19 AM
Subject: Re: [Amps] 8122 x 12
>
> In a message dated 29/12/2004 08:45:18 GMT Standard Time, sm0aom@telia.com
> writes:
>
> About 30 years ago, you could buy such an amplifier from Marconi, the H-1000.
> It used 12 4CX250B's in a distributed wide-band amplifier configuration and
> provided
> 1 kW CW or PEP with 100 mW drive between 1.5 and 30 MHz.
>
>
>
> When I worked on them at Marconi, going above about 28MHz resulted in
> smoke!!! There was an unfortunate resonance in the 10 metre band which was a
> bit of
> a pity.......
> One downside of the distributed amplifer is that half the RF is wasted. The
> signal into the anode lines goes to the load at one end, but the other end
> needs a termination resistor.
>
> Distributed amps were used a lot in 'scopes and rx multicouplers. There's a
> good description in Millan and Taub's Pulse and Digital Circuits. More
> recently, they've been used in wideband microwave amps using GaAsFETS,
>
> 73
> Peter G3RZP
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