Peter -
The setting of the Passband tuner is not significant when doing the Preselector alignment. All
you're looking for is an amplitude peak. Sometimes the Calibrator signal is too strong, especially
on the low bands, driving the AVC too far and making it difficult to see the peak as you tune.
Alternate Calibrator signals vary in strength, so you can pick a lower one on either side (+/- 25
kHz). You can also put a smaller resistor on the ANT jack to reduce the level. Use FAST AVC to
better see the peak.
The resistive loads are to spoil the Q of either T3 and T4 while tuning the other to minimize
interaction of the adjustments. I have found that it really isn't necessary, that you can do just
as good an alignment by going through 3-4 iterations of the adjustments without the loads, as the
interaction refines out.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Peter Ravn wrote:
The otherwise comprehensive R4B preselector alignment instruction does not mention the position of
the passband selector during alignment. Should it be in the same position as during passband tuner
alignment, i.e. with the passband selector to .4, and the passband tuning knob to the shortest of
the curved lines on the panel. Or does it matter at all?
The manual suggests to use the S-meter when adjusting the preselector trimmers for maximum. I find
it much better to use an VTM. Finally the idea of using alignment resistors on S5C and S5D escapes
my understanding.
Thanks
OZ8CTH, Peter
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