[Racal] RA17 37Mcs Filter Alignment

[Brian Goldsmith]

----- Original Message -----
From: "G4GJL"

Does anyone know if ther 37Mcs filter can be aligned reasonably well by ear?
 I cannot get to my Spectrum analyser at the moment due to too much gear in
the shack, and I have a Mk II receiver on the bench.....

I imagine peaking for maximum signal when tuned to centre passband will be
about right?


***** Pete,you can align the 17's 37.5MHz band pass filter without a sweeper
or spectrum analyser but certainly ,not by ear!! The indicating device (VTVM
or 10 Meg digital VM with RF probe) must,repeat must, be shunted to   to
12pF and connected to TP3.Remove the 1 Meg crystal,V9 and V5.
Align the filter in the following order:- L50,C90,81,72,63,55,45,35,24,L28
and L33 several times,for max. output.The input required to produce 1 Volt
should be approx. 2.5 mV.
Email me if you have any problems.
                                                  Brian Goldsmith.