[R-390] RF Transformer Alignment

[Gord Hayward]

> When peaking the RF transformers the technique is to tune to a "lower" 
> frequency, adjust the slug, then tune to a "higher" frequency, adjust 
> the trim cap, and repeat as necessary.  I can understand why the two 
> adjustments are inter-related, can anyone explain how it is that 
> eventually both the lower and the higher frequencies are peaked?


The trimmer capacitor for alignment is usually a small part of the 
overall resonating capacitance so at the high frequency end where the 
main adjustment
is at its minimum, the trimmer has its biggest effect and can be most 
accurately adjusted.  At the low frequency end, the coil is the most 
important so it
is best adjusted there.  Of course changing the capacity will affect the 
coil adjustment but this interaction has the least effect when the cap 
is adjusted at
the high end and the coil at the low end.

Cheers de Gord, VE3EOS

-- 

Gordon L. Hayward, Ph.D., P.Eng.,
Associate Professor, Biological Engineering,
School of Engineering, University of Guelph,
Guelph, Ontario, N1G 2W1.