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Re: [Amps] Initial test of 813 amplifier

To: amps@contesting.com
Subject: Re: [Amps] Initial test of 813 amplifier
From: Vic K2VCO <vic@rakefet.com>
Date: Sun, 15 Aug 2010 07:34:36 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Yes, there are VHF suppressors.

I am thinking that the neutralization was upset because I adjusted it before I 
installed 
the plate transformer, which is not that far from the neutralizing capacitor. 
This, 
combined with the large amount of feedback caused by the missing shielding may 
be the 
reason. Grid-driven tetrodes have a lot of gain!

I think I'm going to finish up the shielding, readjust the neutralization with 
it in 
place, and try it again.

I really don't like arcing because I'm afraid it might damage the capacitor or 
the vacuum 
relay on the output, etc.


On 8/15/2010 4:53 AM, Bill, W6WRT wrote:
> ORIGINAL MESSAGE:
>
> On Sun, 15 Aug 2010 00:04:22 -0700, Vic K2VCO<vic@rakefet.com>  wrote:
>
>> Here's my question: Should I bother with this oscillation at this point? Or 
>> is it normal
>> to have instability when no load is connected to the amplifier?
>>
>> I suppose the fact that there's no enclosure or bottom plate is also a 
>> cause...
>
> REPLY:
>
> The amp should be stable with or without a load (both input and
> output), but the shields should be in place too. Try it again when
> they are.
>
> Is there a VHF parasitic suppressor?
>
> 73, Bill W6WRT
-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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