Retransmission Operating Procedures (cont)

TM 11-5821-28S-12-1

60. Since a monitor capability is not provided in this

NOTE

hookup, an FM-3 radio should be used for contact and

the

one-terminal monitor on operator C-1611/AIC position 3.

secure

e. Radio retransmission is an arrangement of two

voice mode,

radios connected together to provide automatic

volume for

retransmission of signals between two radios that are too

ciphered

far apart to communicate directly with each other.

signals

Frequencies selected for the receiver-transmitters at the

controlled

retransmission site must be such that the transmitting

by the VOL

power of one will not interfere with the signals being

control on

received on the frequency of the other receiver-

the

C-

transmitter.

The frequencies selected should be

1611D/AIC

considered as follows. (1) Fl and F2 must be separated

while plain

by at least 10 MHz.

signals

(2) Do not use frequencies which are separated

volume is

by exactly 5.75 or 24.00 MHz,

controlled

(3) Do not use frequencies which are in the order

by both the

of the second harmonic. For example, the frequency

C-

setting of 30.00, 32.65, and 35.00 will possibly interfere

1611D/AIC

with a radio using 60.00, 65.30 and 70.00 MHz,

and

the

respectively. Changing either the lower frequency or the

HYL-

higher frequency should eliminate the interference that

3/TSEC

may occur.

VOL

controls.

b. Momentarily press the ptt switch on the U-94A/U.

The interrupted tone should no longer be heard in the

earphone and secure voice messages can now be heard

on the monitored channel.

c. To transmit to either station in the secure voice

mode, place the HYL-3/TSEC FUNCTION switch to

XMIT 1 or XMIT 2 as desired; press the ptt switch, wait

for the beep tone and then speak into the microphone.

NOTE

If at any

time it is

desired to

operate in

the

plain

voice mode

with

the

TSEC/KY-

28 installed,

place

the

PLAIN-

CIPHER

switch

the

C-

8157/ARC

to PLAIN.

In the plain

voice mode

the

beep

tone is not

heard in the

earphone

when the ptt

switch

pressed.

d. The channel may be operated without an HYL-

3/TSEC installed and retransmit plain voice signals only.

The HYL-3/TSEC cables No. 53 (RT/1) and No. 55

(RT/2) are attached to the two bypass connectors No.