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[AMPS] L-Net calculations: Am I doing something wrong?

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Subject: [AMPS] L-Net calculations: Am I doing something wrong?
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Date: Fri, 19 Feb 1999 20:22:25 -0500

On Thu, 18 Feb 99 09:20:26 -0600 Jon Ogden <> writes:
>>More to the point, exactly what is the 10M input network, as I asked 
>>weeks ago ?
>I have not gotten back inside the bottom of the amp since then.  And 
>no I 
>don't have the values handy now.  I will get to this eventually.

I'll reply eventually then also.  Sorry for the few day delay in
responding but trying to cram 13 hr days in M-TH and 9 hrs today in order
to cover my trip to NC next week.
My boss wanted that 40GHz PA  testing finished and the 20 piece
evaluation kit shipped. 

>>Have you ever measured any of the LC values?
>>What is the material in the slug tuned coil?
>No idea.  Again, this amp came from an estate sale.  Yes, it probably 
>would have been better to build it from the ground up myself.  Such is 
>life.  I used what it came with.

Which may be the crux of your grief.  Whenever I get an amp in for repair
I ALWAYS rip out the add-on parasitic garbage and proceed  " as designed"

>>What is the wire size and coil diameter?
>Coil diameter is probably about 1/2 inch.  Wire size is #18 magnet 
>if I remember correctly.

The sizes are fine, now to determine the core material.

>>What is the output on 12M, 15M, and descending bands?
>Not set up for 12M, 15M I top out around 1100 if I remember right.  I 
>haven't messed with it too much there.  On 20 I get out about 1400, 40 
>get around 1600 and on 80 I get around 1800.

Almost sounds like a soft tube  OR lossy input coils as the frequency
increases. I try and use 20M ( based on my old 4x1 building days) as an
efficiency guideline. IOW, if I get 65% efficiency on 20M I will not
accept more than a  -10% deviation on other bands. This often requires
playing with Q and minimum C values to get what works....not what looks
good on paper.

Modern tubes offer an even closer tolerance.

>>What is the exact VSWR on all those bands?
>Input VSWR?  Less than 2:1 for sure can be tuned to 1:1.
>>Its my turn for questions. How about only answers for once...
>Well, how can I give answers when I don't necessarily have them.

If you expect guidance you best have answers to questions .  " I dunno"
dont cut it.  "I do not know but will get back to you is fine."

73  Carl  KM1H

>Jon Ogden
>"A life lived in fear is a life half lived."
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