2 2@vc.net
Mon, 8 Oct 2001 21:35:12 -0700

>Aloha Rich and others who have responded,  hope
>I have the following correct:
>In response to my question,
>> >Question:  leave things just as they are now,  or increase
>> >the drive power to bring the SSB peak readings back up
>> >near 1500 watts?  
>Rich  wrote:
>> tune for max out with max drive, provided that the anode 
>> current rating  is observed.  
>Ok,  hmmmm.....
>Yes,  in my Henry Amplifier manual,  Henry publishes a full page
>of your instructions on the importance of correct amplifier
>tuning.  They indicate that the info is reprinted from the March
>1989 QST,  an article by you,  AG6K.  But no specific details!
>Now,  Ok,  here is the tricky part.  
>1. My amp has an Eimac 3CX3000A7
>tube.  The supply voltage,  key up,  is about 6200!  Unit is
>a Henry 8K.  So per your method,  I would set this puppy up
>for the about 5+kW output on CW into the Bird Coax Resistor,
>8890-300 dummy load load,  for starters.
For starters, you need at least 450w drive.  PEP out should be around 9 
assuming 60% efficiency.  

>Presume I would use the 50 wpm dits  for this tune up.  Would
>keep tweaking until the maximum output cababilities
>of the amplifier  seem to have been reached.  Wow,
>have no idea how high that might be!
It's a bunch with 6kVDC. 

>Next step written by others:
> 2. Then adjust the loading control such that the output 
> decreases by about 50-75 watts.  Said to lower IMD.
Not helpful with this bottle because the IMD c, 16db better than the 
cleanest transceiver. 

> 3. Reduce the drive to the amplifier to obtain maximum 
>legal output as seen on your dummy load/peak reading digital 
> meter.

Doing such be reducing mic. gain is best. 
>Depending upon the band,  this would cut the input drive to the
>amp from about 200 to 275 watts down to about 60 or so,  
>approximately to come down from the 5000+ output to the Bird.
>I have NEVER had the amp put out such power(5000+W) to the
>dummy load or anywhere else.  I might be afraid to,  hi.  

5 out is no big deal,  It's not even one S-unit more than the legal 

> These 200+  watt drive powers are from Paul Johnson at Henry in
>the data sheets that came with my amplifier a few years ago.
>4. Assuming that your antenna system is 50R +j0, switch 
> to the antenna system.
>With the tuner between the amp output and the antenna feed, this
>is possible.
>5. You should see very little change in power output as 
> viewed on the peak reading watt meter whether you operate 
> in cw or ssb mode.
True - with a resonant choke PS.  

>6. You can adjust the power output control of the exciter 
> slightly to achieve the maximum legal power output of the 
> amplifier as seen on the in-line peak reading watt meter.
>Ok,  have I got it correct?  Bought the 8K a few years ago in 
>order to have very clean,  cool,  lowest possible distortion and 
>the legal output power.
Sure, but one should not run less power than is needed to communicate.  
If it takes 9 to rise above jammers/sociopaths, that's just fine.  "Speak 
softly and carry a big stick."   

cheers, Jim

-  R. L. Measures, 805.386.3734, AG6K, www.vcnet.com/measures.  

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