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[AMPS] Stability Question

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Subject: [AMPS] Stability Question
From: (Jon Ogden)
Date: Tue, 9 Feb 1999 20:08:54 -0600
>>Just one of my tubes.  Perhaps it's a problem with the tube and not 
>>amp.  I've a suspicion that this tube is possibly flaky.  Bandswitch 
>>position is 10m. 
>Does that tube produce more power than the rest?  Is it a different

Both are Eimac.  My only other "good" tube was destroyed by my 
oscillation last spring, it turns out.  The filaments don't even light!

I haven't really quantified which tube puts out more power since I don't 
have a "good" amp to test them out in.  So I can't answer your question 
right now.

>>Yes, I do.  I haven't measured that though.  I will try that this 
>>evening.  How would one do this?  Just start the amp oscillating and 
>>tune through the GDO to find the oscillating frequency?  Do I hold the 
>>GDO just above the PA cabinet?
>You probably need 3 hands. Just barely start oscillating and tune the
>GDO; keep it as far away as necessary to get a half scale reading. But
>keep one eye on the tube and be ready to hit the kill switch if it takes
>off in melt down mode.

That's what I had figured I do.  I'lll try it eventually.

>Depending upon the tank coil spacing a steel lid may offer sufficient
>detuning effect without absorbing too much good RF.
>Bottom line...I think you should concentrate on improving the 10M
>efficiency while watching for instability with other tubes.

Well, I would agree with you here, Carl.  After the recent discussions on 
the B&W tank coil and position of tune input circuitry, I am putting all 
other stability issues on hold.  Looks like I am going to go through yet 
another reconstruction project with this thing.  This time to modify the 
B&W tank coil and also to change the position of my input circuits.  Only 
question on the coil is how to add significant inductance on 80m easily.

BTW, how much do you want for a complete set of Arco trimmers and 

C'est la vie!  Learn, learn and learn again..............



Jon Ogden
KE9NA    <--- CHECK IT OUT!  It's been updated!!!!!

"A life lived in fear is a life half lived."

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