[Amps] Linear Amplifier Tuning---PROPERLY!

[Ron Youvan]

   Eddy Swynar wrote:

> Here's exactly what Tom says in his website which you directed me to:
> The last few tuning steps should always be:

> Load the amplifier to maximum obtainable output at full exciter drive (without exceeding amplifier short term overload ratings)
> After that, advance the loading control very slightly beyond that point (towards less capacitance).

> No mention of having to "re-tweak" the plate tuning control at all, that I can see---so does this mean "hands off" that particular knob, or that the writer is naturally assuming that one would naturally touch-up that control as a matter of course...?

   I think I understand the procedure, is it quite bad to under-couple the output of any amplifier, 
this is like "loosing the load." (something gone open)
   When the load is any less than optimum the device's RF output Voltage rises rapidly.  This can 
cause arcing and damage to such things as insulation and coupling capacitors not to mention "RF 
choke" damage.  (if any)

   The slight over coupling is intended to take you away from the "ragged edge" that you might have 
tuned to, this is so if "things" as they warm up, change the loading you will be much less likely to 
notice that burning smell.  (burning plastic etc.)

   No tuning should follow the "final" loading adjustment.  (tweak)
-- 
    Ron  KA4INM -    Ron  KA4INM - Did you know ...
                     ... that no-one ever reads these things?