Cobra 29ltd Stcb Tranciever Manual

OPERATING INSTRUCTIONS FOR YOUR
40 CHANNEL
CITIZENS BAND 
2-WAY MOBILE RADIO
Model
29 LTD ST
Cobra Electronics Corporation
6500 W. Cortland Street
Chicago, IL 60707
PRINTED IN HONG KONG ©COBRA ELECTRONICS CORP. 1997 480-113-P-001 

The Citizens Band lies between the shortwave broadcast and 10-meter Amateur
radio bands, and was established by law in 1949. The Class D two-way commu-
nications service was opened in 1959. (CB also includes a Class Acitizens band
and Class C remote control frequencies.)
FCC regulations permit only ÒtransmissionsÓ (one party to another) rather than
ÒbroadcastsÓ (to a wide audience). Thus, advertising is not allowed on CB
Channels because that is Òbroadcasting.Ó
“Cuts Static coming in, adds Punch going...

Specifications (cont.)
GENERALChannels40 
Frequency Range26.965 to 27.405 MHz.
Frequency ControlPhase Lock Loop (PLL) synthesizer.
Frequency Tolerance0.005%.
Operating Temperature Range-30¡C to + 50¡C.
MicrophonePlug-in dynamic.
Input Voltage13.8VDC nom.(positive or negative ground).
Current DrainTransmit: AM full mod., 1.5A(maximum)
Receive: Squelched, 0.3A; full audio output, 1.2A
(nominal).
Size8 5
/
8Ó D  x 79
/
32Ó W  x 2 13
/
64Ó H .
Weight4 lbs.
Antenna ConnectorUHF, SO-239.
Semiconductors26...

5
Installation (Cont.)
3.
Connect the antenna cable plug to the standard receptacle on the unit. Most
CB antennas are terminated with a type PL-259 plug which mates with the
receptacle marked ANT.
4.
Connect the red lead of DC power cord to +13.8 VDC. In automobile instal-
lations, +13.8 VDC is usually obtained from the accessory contact in the
fuse box. This prevents the set being left on accidentally and also permits
operating the unit without the vehicles engine running.
Before installing the CB...

7
Installation (Cont.)
Ignition Noise Interference
Use of a mobile receiver at low signal levels is normally limited by the presence
of electrical noise. The primary source of noise in automobile installations is
from the alternator and ignition system in the vehicle. Under most operating
conditions, when signal level is adequate, the background noise does not present
a serious problem. Also, when extremely low level signals are being received, the
transceiver may be operated with vehicle engine turned...

Operation (Cont.)
9
6.
DELTA-TUNE.For normal operation, set this control to the center posi-
tion. This feature has several uses and can greatly enhance receiver oper-
ation. If a received signal is slightly off frequency, the Delta-Tune control
can be used to Òfine-tuneÓ your receiver. Fine tuning is accomplished by
listening for a more readable signal at the speaker or by noting the S-
meter reading when the Delta-Tune control is operated.
Another use of this control is eliminating adjacent...

Operation (Cont.)
11
C. Rear Panel1.
PUBLIC ADDRESS:An external 8-ohm 4.0 watt PAspeaker may be connect-
ed to the PASpeaker Jack when this unit is used as a public address system.
The speaker should be directed away from the microphone to prevent acoustic
feed-back. Physical separation or isolation of the microphone and speaker
must be employed when operating the PAat high output levels.
2.
EXTERNALSPEAKER:The External Speaker Jack is used for remote receiver
monitoring. The external speaker should have...

13 12
Operation (Cont.)
Operating Procedure to Receive
1.
Be sure that the power cord, antenna and microphone  are connected to the
proper connectors before proceeding further. The PA/CB  should be in the
CB position.
2.
Turn the radio ON by rotating the VOLUME CONTROLclockwise.
3.
Set the RF GAIN CONTROLfully clockwise.
4.
Set DELTA-TUNE CONTROLto center(click-stop) position.
5.
Rotate SQUELCH CONTROLcounterclockwise until incoming signal is heard.
6.
Set the CHANNELSELECTORSwitch to the desired...

15 14
Maintenance and Adjustment
The COBRACB transceiver is specifically designed for the environment encoun-
tered in mobile installations. The use of all solid state circuitry and its light weight
result in high reliability. Should a failure occur, however, review the following,
then if necessary, replace parts only with identical parts. Do not substitute. Refer
to the schematic diagram and parts. 
1.Check connections to the source of power and make sure it is the 13.8 VDC
required to operate your...

Appendix (Cont.)If You Think  You Need Service