[Kenwood] TS940S "S" meter set up query

[Martin Sole]

John,

As with many of the alignment procedures in the 940 service manual reading
them several times might give you several ideas about what is expected. On
page 82 of the 940 service manual is the statement 'INPUT : 0dB (5uV) note
that the 5 is a misprint, should be 0.5. In the TS930 service manual on page
78 and 79 is a reference to Japanese SSG 0dB, American SSG 0.5uV. It is now
necessary to understand if they are talking about uV in open circuit,
unloaded, e.m.f. format or loaded p.d. format. Most European signal
generators/service monitors have a means to display or calculate their
signal generator output in either format.

>From the Kenwood data it can be seen that their use of 0dB (meaningless in
the context given without a terminator) is actually 0dBuV where 1uV is the
open circuit value. I don't know the TF2008 but you will need to determine
what the attenuator scale is calibrated in. If it is uV e.m.f. then use 1uV
for every reference of 0dB and double or half it for every change of plus or
minus 6dB respectively. If the attenuator is scaled in uV p.d. then use
0.5uV for for every reference of 0dB and again double or half it for every
change of plus or minus 6dB respectively. If the scale is marked in dBm then
-113dBm equals 0.5uV p.d. (1uV e.m.f.)

In the TS940 S meter alignment section it says to set the 0 point with the
generator at 0dB this is 0.5uV p.d. or -113dBm. S1 is set with the generator
at 8dB this is -105dBm or 0.9uV p.d. S9 is set with the generator at 40dB
this is -73dBm or 50uV p.d. and S9+60dB should occur with a generator level
of 100dB or -13dBm, 50mV p.d. You will need to through the procedur a few
times to get everything to match if you are starting from scratch.

Regards es GL
Martin HS0ZED G4UQF


-----Original Message-----
From: kenwood-bounces at mailman.qth.net
[mailto:kenwood-bounces at mailman.qth.net] On Behalf Of John E. Cleeve
Sent: 17 February 2006 19:38
To: kenwood at mailman.qth.net
Subject: [Kenwood] TS940S "S" meter set up query

I remember that in the past there was a discussion on setting up the S meter
adjustments for the TS940s.. one point raised was that the Japanese signal
level settings specified, caused some confusion. I would be grateful if
someone could jog my memory. I do have a copy of the service manual, and the
use of a Marconi TF2008 signal generator......thanks, John. G3JVC. 


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