TM 11-6625-586-45
(16) Adjust the LO RF UV dial until 10K ap-
pears under the hairline.
MHz.
such that 10KUV is under indicator Line. Turn
5-6. High RF Voltage Range and Accuracy
RF SET TO LINE control knob such that RF
Adjustment
meter reads ton "red line."
a. Connect HIRF terminal of unit under test
bp. Repeat steps as through bl. Record all data
under 80 MHz. Calculations and procedure ex-
terminal of multimeter.
actly the same as prescribed for 50 MHz case.
b. Set OPERATE-OFF-STANDBY switch to
bq. If an out of tolerance voltage is found, ad-
OPERATE.
just as follows:
c. Turn FUNCTION switch to MOD OFF and
(1) Connect LO-RF terminal of unit under
RF OUTPUT switch to 62.5 KUV.
test through Z105 and 50-ohm adapter to multim-
eter.
NOTE
(2) Check that FUNCTION switch is set to
If any multimeter reading is not within toler-
MOD OFF and RF OUTPUT switch is set to 0
ances, proceed to step i.
10KUV.
(3) Loosen the power probe stop on piston
lowing frequencies: band A 18 and 26 MHz, band
attenuator assembly A1A2.
B 26 and 37 MHz, band C 38 and 54 MHz, and
(4) While looking in the front end of the
band D 54 and 80 MHz.
piston attenuator, turn the LO-HI RF SET TO
e. At each frequency, the multimeter should
LINE control until the vertical pick-up wire al-
indicate between 47 and 78 kuv.
most comes in contact with the harmonic mode
suppressor.
f. Turn RF OUTPUT switch to 125 KUV and
(5) With BAND SWITCH and RF TUN-
repeat step d. At each frequency, the multimeter
ING control select frequency of 80 MHz.
should indicate between 94 and 156 kuv.
(6) Adjust piston attenuator trimmer capac-
g. Turn RF OUTPUT switch to 250 KUV and
itor for maximum output on multimeter.
repeat step d. At each frequency, the multimeter
(7) Adjust LO-HI RF SET TO LINE con-
should indicate between 187.5 and 312.5 kuv.
trol for red line indication on IF UV RF SET TO
h. Turn the RF OUTPUT switch to 500 KUV
I
LINE meter.
and repeat step d. At each frequency, the mul-
(8) With multimeter on 10 MV scale, ad-
timeter should indicate between 375 and 625 kuv.
just piston attenuator with LO RF UV control for
i. Turn the RF OUTPUT switch to 250 KUV.
2 db reading.
j. Set BAND SWITCH to band A and select a
(9) Tune through band D with RF TUNING
frequency of 18 MHz with RF TUNING control.
control, keeping the IF UV RF SET TO LINE
k. Adjust the LO-HI RF SET TO LINE con-
meter set to red line, and observing the db spread
trol for a 250 kuv indication on the multimeter.
on multimeter.
l. On RF attenuator switch board S1, adjust
(10) Adjust piston attenuator trimmer ca-
HI-RF METER CAL control S1R1 for a .55 or
pacitor for least amount of db spread over the
red line indication on the front panel IF UV RF
entire band.
SET TO LINE meter.
(11) Check db spread on bands A, B, and C.
The maximum allowable db spread over any band
5-7. RF Output Impedance
is 1.5 db. Readjust piston attenuator trimmer,
a. Connect LO-RF terminal of unit under test
if required.
through impedance matching network Z105 to HI
(12) Turn LO RF METER CAL control R61
terminal of RX meter.
fully clockwise.
b. Turn OPERATE-OFF-STANDBY switch
(13) Adjust power probe for red line indica-
to STANDBY.
tion on IF UV RF SET TO LINE meter with LO-
c. Turn RF OUTPUT switch to 0-10KUV.
HI RF SET TO LINE control.
(14) With LO RF UV control adjust piston
cies of 20 MHz, 50 MHz and 80 MHz.
attenuator for one-half the amount of db spread.
e. At each frequency, the impedance measured
(15) Set piston attenuator and power probe
should be 50 10 ohms + j 0 10 ohms.
stop.
5-6
