[Amps] Question for the tetrode experts

[Vic K2VCO]

Q should be about 12. I have discovered that the screen meter is the tuning indicator. I 
have my trip point set at 35 mA, so I have so far kept it at 25-30 mA. I have still only 
tried it on 40M. I'm going slowly, trying to fix all of the issues before something gets 
damaged.

On 11/8/2013 1:30 PM, Peter Voelpel wrote:
> What is the loaded Q of your Pi circuit?
> Is that sharp tuning with the load capacitor on all bands?
>
> When tuning the anode capacitor, peak screen current with it and use load
> for the correct screen current of about 35mA with a good tube.
> That should coincidence with about 1500-1600W out.
>
> 73
> Peter
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Vic K2VCO
> Sent: Freitag, 8. November 2013 22:09
> To: N1BUG
> Cc: amps at contesting.com
> Subject: Re: [Amps] Question for the tetrode experts
>
> I have a vernier on it. Maybe I exaggerated -- it's not all that bad, just
> different. It
> is smooth. I just need to get used to it. A plus: the screen meter is very
> useful as a
> tuning indicator!
>
> On 11/8/2013 1:01 PM, N1BUG wrote:
>>> Tuning is VERY touchy. You really have to have the loading right or the
> screen current is
>>> excessive in either direction.
>>
>> None of my 4CX1000A or 4CX1500B amps were all that touchy, from 1.8 to 144
> MHz. Screen
>> current does vary with loading, from negative through zero to positive,
> but it is a smooth
>> and easily controlled change provided the loading capacitor has some
> reasonable rate of
>> adjustment. I prefer vacuum variables, but if using an air variable I put
> a vernier drive
>> on it.
>>
>> With vacuum variable tune and load caps in a pi network, I have no problem
> going from band
>> to band by using logged presets. Of course the presets have to be changed
> if I make any
>> change to the antenna system, and tuning needs to be verified if there is
> any possibility
>> of weather conditions affecting the antenna (ice or snow).
>>
>> 73,
>> Paul N1BUG
>

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