[R-390] R-390 IF adjustment of .1 1. bandwidth

[David Wise]

There isn't any trim to bend the crystal, you just have to take what you get.

L503 is adjusted to resonate at the crystal frequency in order to get the widest 1kHz bandwidth.  (R502 and R503 "spoil" L503/C524 by a calibrated amount to get 1kHz or 100Hz respectively.)

I think C520 is adjusted to balance out stray capacitance at the crystal's parallel-resonant frequency.

Dave Wise

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Roger Ruszkowski
Sent: Monday, October 21, 2013 1:38 PM
To: R-390 at mailman.qth.net
Subject: [R-390] R-390 IF adjustment of .1 1. bandwith


Bill,

Now that we have counters the question becomes how to 
adjust the trim cap to pull the crystal onto 455 and get the 1Khz
band pass also centered on the 455.

As the TM came before counters, the TM does not 
address this adjustment process.

Fellows how should we conduct this adjustment process?

Roger.