LF: Re: M0BMU mods to the G0MRF PA

["James Moritz" <james.moritz@btopenworld.com>]

Dear Warren, LF Group,

It is possible to add taps to the output transformer for different output 
powers, although adding the extra bits of wire will tend to increase leakage 
inductance and make the construction more complicated. Personally I have 
found varying the DC supply voltage is mare convenient, as G4WGT has done. 
If you do have a tapped output winding, I would suggest limiting yourself to 
one or two taps only - how many levels of output power do you really need 
anyway? If you just require a low power setting for tuning-up purposes, and 
are stuck with a fixed-voltage PSU, an alternative is a large resistor 
inserted in series with the DC supply. Although it is inefficient, it does 
provide inherent current limiting, making it hard to blow up the PA while 
tuning.
Cheers, Jim Moritz
73 de M0BMU