[R-390] RF Alignment Questions

[DJED1 at aol.com]

I'd say use the signal generator and align per the manual.  A wider  
bandwidth like 8 Kc is good, especially if your generator drifts a bit.   But all you 
have to do at this point is set the frequency on the radio and tune  the 
generator to peak the signal in the passband.  Remember that the  receiver should 
be in manual gain control setting, and the generator output  should be set for 
the -4VDC at the diode load using your VTVM.  As others  have noted, there are 
specific high and low frequencies in each RF band (e.g.,  1-2, 2-4, 4-8 etc) 
at which the capacitor trimmers or slugs are tuned, so follow  the 
instructions.  I noticed that these tuning frequencies are also printed  on the RF module 
cover for quick reference.  
Other things to check- note that there are two capacitors in the first RF  
transformer- the front one is a balance adjustment, and the rear one is the  
trimmer.  You can check the balance if you intend to use a balanced  twinlead 
type feedline.  
Watch how the capacitance trimmers respond as you turn them: you should get  
two peaks as you turn each- otherwise your at the limit of capacitance and may 
 need to change a fixed capacitor later.  (I wouldn't bother unless the  
measured performance is not up to spec)
You may need to give some caps a shot of Deoxit to clean the contacts- I  had 
to do that to one of my caps when doing my recent alignment.
Sounds like you're making good progress- enjoy
Ed
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