Installation - TM-11-5820-554-120086

TM 11-5820-554-12

ELODOO38

Figure 12-2. CU-2004/U and Collins KWM-2/2A, hookup diagram.

marked SHUNT. Connect the ground strap from the

12-3. Installation (fig. 12-2)

terminal marked SERIES to the ground terminal.

Set the ANT OUTPUT C control to 24-00. Set the

SERIES COIL to zero.

Keep the antenna lead-in inside the building as short

f. Switch the wattmeter to the 200 WATTS

as possible. If the coupler is used inside an aircraft,

REFLECTED position (or use an swr meter).

the lead-in inside the aircraft should be as short as

g. Set the Collins KWM-2/2A EMISSION

12 inches. This lead length influences the selection

switch to LOCK.

of a mounting position for the coupler. With a

h. With the COAX INPUT C control maintain

heavy conductor such as shield braid, attach the

the Collins KWM-2/2A plate current at maximum,

GROUND terminal of the coupler to a good ground.

but no higher than 210 ma.

Ground radials buried below the surface of the

i. With the SERIES COIL control, find the

ground may be necessary. If the installation is in an

plate current dip, and watch the reflected power

aircraft, attach the ground wire to the skin of the

indication at the same time.

aircraft.

j. When properly tuned, the COAX INPUT C

control will maintain loading and should be set for

12-4. Tuning Procedure

plate current between 200 and 230 ma. The

a. Connect the Collins KWM-2/2A, 302C 3

SERIES COIL control maintains antenna resonance

directional wattmeter and antenna coupler as shown

and should be used to dip the plate current and the

in figure 12-2. Leave the coaxial lead disconnected

reflected power indications to minimum.

from the coupler at this time.

k. If the COAX INPUT C control reaches

b. Connect a dummy load to the coaxial lead

maximum (dial reads 10), add in one of the 500-f

from the directional coupler. Use any 50-ohm load

capacitors, using one of the COAX INPUT C

capable of dissipating the power output expected

jumpers.

from the transmitter.

l. If a unity swr still cannot be obtained,

c. Tune and load the Collins KWM-2/2A

connect the antenna to the terminal marked SERIES,

according to paragraph 3-12.

and repeat h, i, and k above at the same time

d. Remove the dummy load from the circuit,

adjusting the ANTENNA OUTPUT C along with

and connect the coaxial lead to the antenna coupler

the controls in h and i above. (Maximum C is

in place of the dummy load.

obtained when the dial reads O.)

e. Put the COAX INPUT C jumpers in the

SPARE jacks. Set the COAX INPUT C dial to

zero. Connect the wire antenna to the terminal

12-2