[AMPS] Re: CW/SSB Tune Up

[Tom Rauch]

> load,  of course.  Bird 43 with a 5kW slug was of no use,
> it is way too slow and does not respond to the 50 wpm
> dits.

Even if the metering system does not indicate peaks, it is generally 
good for geting optimum tuning on long pulses. The only 
requirement is the rise and fall be short compared to the flat time at 
the top. 

There is no magic with speed or duty cycle used, except as it 
relates to average dissipation in the elements.
 
> Anyway I found that once the tune and load controls were
> at resonance,  they did not seem to need to be tweaked
> as the drive was increased beyond 100 watts or so.  

The load is not resonanted. It sets the anode load impedance. The 
plate control is used to set resonance.

> max C).  With 200 watts drive,  factory data shows tune dial at 160,
> and the load C is lower, at a dial of 460 or seemingly significantly
> heavier loading of the output.  Maybe I should do this all over again
> and just use constant key down for the final tweaking.

A pulse should be fine with almost any meter, as long as the rise 
and fall times are short compared to the on time. The meter does 
NOT have to indicate peaks to let you tune the PA properly on a 
string of pulses. 
 
> Well,  maybe all of this fiddling is of no point,  as I lower
> the drive well down before going to the antenna set up!

Since most exciters have considerable overshoot, it is always a 
good idea to overload the tank somewhat. You can do that by 
opening the load control slightly past the point of maximum output 
at full carrier drive. The plate control should always be peaked for 
maximum output, unless the manufacturer tells you to do 
something else because of unstable feedback or something equally 
odd.

Grounded grid amps are really very forgiving, but it is best to load 
on the heavy side if you do make an error.
73, Tom W8JI
W8JI@contesting.com 

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