[Amps] AL 811

[R@contesting.com]

On Jul 12, 2005, at 9:13 PM, W5WRL wrote:

> Folks
>
> I am interested in changing the relay on the amp to provide something
> quieter. Do you have any suggestions? Vacuum relays? If so, who?

> Is there a way to make the unit QSK?

Hello, Bill -- If you can: follow a schematic, and solder, the circuit 
on Fig. 7B on my Web site will fill the bill.  The T/R speed is c. 2mS, 
so it's good for up to about 40wpm QSK. For SSB-VOX it is quite 
delightsomely quiet.  I sell a parts kit for such that includes the 
Matsushita high-speed RF reed relay* for the RF input and, if needed, 
the high speed vacuum relay for the RF output.  The builder furnishes a 
piece of perf-board that will fit in his/her amplifier.
-  Free, unsolicited advice:  The AL-811 has a reputation for parasitic 
oscillation.  Thus, provided that you don't have a free source of 
811As, it might be prudent to reduce the VHF gain of the 811As by 
reducing the Q of the VHF suppressors.  Also, if yours has a HF 
"neutralization" circuit like that used somewhat less than successfully 
in the Heath Warrior and Gonset GSB-201, removing it will improve VHF 
stability

*  Matsushita RSD-12V relay (1mS) sold separately for $9.91.
>
>
>
> 73,
>
> Bill Lawless - W5WRL
> ARRL WTX Section Manager
>
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Rich Measures, 805.386.3734, AG6K, www.somis.org