[Kenwood] R-5000 "S" meter cal, found the problem

[Phil Atchley]

Hello all
Well, I found out why I couldn't set VR5 for S9+60dB (per the manual
procedure)  The VR5, VR3 and VR1 all interact.  In this case, VR5 was so far
out of adjustment that when you adjusted VR3/VR1 per the manual, VR5 was too
far off to have any effect!  I figured it out when I set the generator to
92dBu and the meter stayed pegged no matter where I set VR5.  So, I backed
down to 32 dBu (S9), turned the S meter down some with VR5, readjusted
VR1/VR3 for S2/S9 like they should be then rechecked S9+60.  Voila!  It was
just slightly over S9+60 instead of the needle banging "pegged".  Going back
and forth a few times brought the S meter into where it tracked pretty
close.  NOT perfect, but close enough. I imagine that to get any closer my
generator would need a lab quality calibration at a cal lab and then take
more time than I want to spend on it.

ONE OTHER NOTE:  The set is much 'quieter' with no signal input.  Whoever
had gotten "screwdriver-itus" in this set had turned VR1 (IF Gain) up quite
a bit higher than it should be. I guess that they thought that if the "S"
meter reads much higher, the set is that much more 'sensitive'!!!  My local
blockbuster BCB station now reads S9+40 and has no distortion where it
previously pegged the meter and had to have 20dB of attenuation inserted to
prevent overload distortion.  Yet, with the signal generator I can easily
hear a 1uV 50% modulated AM signal clearly in the AM mode at 14.1MHz, so the
receiver is plenty sensitive!  I didn't do a MDS (minimum discernable
signal) on the set as I'm not certain of how precision it's level is anyway.
The lowest level I can get out of it is supposedly .6uV with it's internal
attenuators/meter cal.

73 de Phil  KO6BB
Loving home provided for wayward Boatanchor Receivers
ko6bb@elite.net
Merced, Central California
37.18N 120.29W CM97sh



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