[Amps] CW and High Voltage

[gdaught6@stanford.edu]

On 4 Sep 2005 at 7:17, R.Measures wrote:
> On Sep 3, 2005, at 10:53 PM, Phil Clements wrote:

< snip, snip : other attributions >

> >>>> Cutting the drive back too much will indeed cause a good size
> >>>> mismatch

< more snips >

> Most of the manuals that I have read give instructions that say to
> reduce drive during tuneup.  Do you agree with this procedure?

In my opinion, we may be addressing what shouldn't be a problem.  
What I mean is this:  the FIRST TIME I tune a new (or modified) amp, 
I believe it's prudent to start with reduced drive, so that I don't 
make a flash-bulb of the control grid (and/or screen grid) and seek 
the proper settings for the tune and load capacitors.  Then the drive 
can be increased, with the capacitors adjusted to get the designed 
value of power out, and all meters reading the proper numbers.  I 
increase the loading a tiny bit until the output drops just 
perceptibly.  Then, I write down the settings, and I can go to 
another band, and perform a similar exercise.  

Now I can return to the original band, duplicate the settings and 
transmit!  I know that I'm matched.  There's certainly no need for 
reduced drive.  In fact, there's no need for "tuneup" if I'm using 
the same antenna, etc.  At most, I'll twiddle the "tune" knob to peak 
the output if I've gone from 7.005 to 7.255 MHz or some such within 
the band frequency change.  (Although I don't know why anyone would 
want to be on 7.255 8>)

If I want to reduce power on CW, I'll turn down the "RF out" on my 
transceiver.  On SSB, the same thing works, but the "Mic gain" is my 
choice.  There's no need to redo the whole tuning thing.

Does this seem to be a reasonable approach?

73,



George T. Daughters, K6GT