[Amps] 8122 x 12

[Karl-Arne Markström]

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 at aol.com>
To: <sm0aom at telia.com>; <avilaseca at bluewin.ch>; <wa1hco at adelphia.net>
Cc: <amps at 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 at 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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