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mc (AN/USM-26 indicates 43.000
(9) Disconnect the 411A from J20. Re-
mc 25 kc).
place A14. Connect the 411A to
(5) Adjust the 721A output voltage
A9J4.
until the ME-26B/U indicates ex-
(10) S e t t h e r e c e i v e r - t r a n s m i t t e r
actly +4.0 volts dc. Record the fre-
BAND switch to 53-75.
quency indicated by the AN/USM-
mitter mc tuning knob in l-mc in-
crements from 53.50 to 75.50 mc,
(6) Adjust the 721A output voltage until
observe the indications on the ME-
the ME-26B/U indicates exactly
26B/U and the 411A.
+3.0 volts dc. Record the frequency
(12) The ME-26B/U indication should
indicated by the AN/USM-26.
be the same as that in (2) above;
(7) Subtract the indication obtained in
the 411A indication should be the
(6) above from that obtained in (5)
same as that in (4) above.
above. This value, which is the vfo
(13) If any of the indications obtained
sensitivity (kc/volt), at the lower
above are not normal, proceed to
end of the band, should be 300 kc
30.
the alignment procedure given in
c and d below.
(8) Reset the mc tuning knob to 51.50
mc and the 721A output (indicated
c. Preparation for Alignment.
by the ME-26B/U) to +3.6 volts dc.
(1) Prepare the following equipment:
The AN/USM-26 should indicate
(a) Transistor Power Supply 721A.
63.000 mc 25 kc.
(b) Frequency Meter AN/USM-26.
(9) Adjust the 721A output voltage until
(c) Multimeter ME-26B/U.
the ME-26B/U indicates exactly
(d) Rf Wattmeter AN/URM-43A.
+4.0 volts dc. Record the frequency
(2) Connect the positive lead of the
indicated by the AN/USM-26.
721A to A9J3. Connect the GRD lead
(10) Adjust the 721A output voltage until
the ME-26B/U indicates exactly
sis.
+3.0 volts dc. Record the frequency
(3) Connect the AN/URM-43A to ANT
indicated by the AN/USM-26.
connector J2.
(11) Subtract the indication obtained in
(4) Connect the ME-26B/U across the
(10) above from that obtained in
721A output. Adjust the 721A until
(9) above. This value, which is the
the ME-26B/U indicates exactly
vfo sensitivity at the upper end of
3.6 volts dc.
the band, should be equal to the
(5) Connect the AN/USM-26 ,to A14J2.
indication obtained in (7) above
within 15 kc.
panel controls as follows:
(12) Reset the 721A output voltage to
(a) BAND switch at 30-52.
exactly -3.6 volts dc as indicated
(b) Mc and kc tuning knobs for 30.50
by the ME-26B/U.
mc.
(13) If the indications obtained in the
(c) Function switch at ON.
procedures given in (7) and (11)
d. Alignment Procedure.
above are within limits, proceed to
(17) below. If the indications are
(1) Rotate the mc tuning knob to 31.50
greater than 15 kc apart, proceed
mc. Adjust T1 until the AN/USM-26
to (14) below.
indicates 43.000 mc 25 kc.
(14) If the frequency difference given in
(2) Rotate the mc tuning knob to 51.50
(11) above is less than that given
in (7) above, adjust C8 clockwise
indicates 63.000 mc 25 kc.
until the vfo frequency is decreased
(3) Repeat the procedure given in (1)
50 kc, as indicated by the AN/USM-
and (2) above until no further ad-