Midland 77-857 User manual

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40-CHANNEL MOBILE TRANSCEIVER
OWNER'S GUIDE

FEDERAL COMMUNICATIONS COMMISSIONS REQUIREMENTS
Your new Midland 77-857 is a combination receiver-transmitter designed and built for licensed
Class D operation on any of the 40 frequencies designated for citizens band use by the Federal
Communications Commission. You are required to read and understand Part 95 of the F.C.C. rules
and regulations prior to operation of this unit. You are
also required to complete F.C.C. form 505 and
submit it to the FCC, GETTYSBURG, PA. 17326 in order to receive your license to operate this unit.
F.C.C. regulations will be violated if you transmit with this unit without complying with procedures
explained on F.C.C. temporary license form 555-B.
You may use Form 555-B as a temporary permit while your regular Form 505 application is being
processed by the F.C.C.
Both Forms are packed with the transceiver along with a copy of part 95 regulations for your use
and convenience.
NOTE: The technical information, diagrams, and charts provided in this manual are supplied for the use of a qualified
holder of a first or second class radiotelephone license in servicing this transceiver. It is the user's responsibility
to see that this unit is operating at all times in accordance with the F.C.C. Citizens Radio Service regulations.
If you install or service your own transceiver, do not attempt to make any transmitter tuning adjustment. Trans-
mitter adjustments are prohibited by the F.C.C. unless you hold a first or second class radiotelephone license or
are in the presence of a person holding such a license. A Citizens Band or Amateur license is not sufficient.
When service is performed by an authorized and licensed person, care must be taken in the replacement of
parts to use only authorized parts, in order not to void the type acceptance of this model.
Midland International Corporation, Communications Division, hereby certifies that this unit has been
designed, manufactured and F.C.C. type accepted in accordance with Part 95 and Part 15, Subpart C of the
current F.C.C. rules and regulations as of the date of manufacture.

OWNER'S GUIDE
Your 77-857 is a versatile, professional quality transceiver and we strongly suggest that you read
this Owner's Guide carefully before operation so that you may receive full benefit from its many
features.
OPERATING CONTROLS CONNECTORS AND THEIR FUNCTIONS
VOLUME CONTROL/POWER SWITCH
This turns the power on or off.
This controls the sound output from the speaker when receiving or from the public address (PA)
speaker connected to the PA jack on the rear panel. The volume control does not affect transmitting
output.
PA/SQUELCH CONTROL
This transceiver has been equipped with a simple PA (Public Address) amplifier system. When operat-
ing the transceiver as a PA, place the control in the PA (fully counter-clockwise) position and connect
a suitable 8-16 ohm PA speaker to the EXT. CB/PA Jack on the rear panel. Press the Push-to-Talk bar
on the microphone and talk into the microphone, then your voice will be heard from the PA speaker.
For regular 2-way communications, turn the control clockwise. Further turning operates the squelch
and quiets the receiver when signals are not being received and allows a quiet standby operation. It
functions only in the receive mode and does not affect the receiver volume when signals are being
received.

To adjust, when no signals are present, rotate the control clockwise until the receiver is silent. In-
coming signals will automatically release the squelch. Careful adjustment is necessary as a setting too
far to the right will not allow weaker signals to release the squelch.
ANL -
OFF SWITCH
An Automatic Noise Limiter, (ANL) circuit is provided for reducing undesirable atmospheric noise.
To operate the ANL circuit place the switch in the ANL position. To cut off the circuit, place it in
the OFF position.
EXT. CB -
OFF SWITCH
Model 77-857 has been designed to enable you to monitor CB calls through a P.A. speaker connected
to the "EXT. CB/PA" jack on the rear panel.
For example: if you leave your car and you are expecting a call on your radio, simply put the EXT.
CB-OFF switch in the "EXT. CB" position. This channels incoming calls through the P.A. speaker
and cuts off the built-in speaker (or speaker connected to the "EXT. SPEAKER" jack). It is possible
for you to transmit while the unit is in the "EXT. CB" mode although the unit's built-in speaker (or
external speaker) will not be operational until the EXT. CB-OFF switch is moved to the OFF position.
The P.A. function of your unit is located on the squelch control. To use your unit as a P.A. amplifier
simply turn the squelch control counter-clockwise to the P.A. position. When the unit is in the P.A.
mode, it will not act as an external CB monitor.
CHANNEL SELECTOR SWITCH
This controls both transmitter and receiver frequencies simultaneously and may be set to any of the
40 channel positions indicated. All necessary crystals are supplied for full 40 channel operation.

DELTA TUNE CONTROL
This is a 3-position switch which varies the receiving frequency for about ±1 kHz. This enables you
to receive stations transmitting slightly off frequency. Place the control in one of the three positions
where the clearest reception is obtained. This control does not affect transmitting frequency.
S/RF POWER METER
This gives the relative strength of incoming signals when receiving and RF power output when trans-
mitting.
ANTENNA CONNECTOR
Used for antenna connection, matches PL
-
259 standard type.
EXT. SPEAKER JACK
Used for an external speaker (8 ohms) connection.
This jack accepts a standard (3.5 mm0) 2 circuit phone plug. When the plug is inserted into the jack,
the built-in speaker is automatically disconnected.
EXT. CB/PA JACK
This will be used for connection of PA speaker, see "PA/SQUELCH" control and "EXT. CB-OFF"
switch in this manual.
DC POWER CONNECTOR
Used for connection of DC power cord supplied with the unit.

CHANNEL SELECTOR
VOLUME CONTROL/POWER SWITCH
S/RF POWER METER
ANL SWITCH
EXT. CB-OFF SWITCH
OPERATION OF CONTROLS
PUSH-TO-TALK MICROPHONE MIC JACK
PA/SQUELCH CONTROL

DELTA TUNE

•
QC POWER CONNECTOR 
ANTENNA CONNECTOR
EXT. CB/PA JACK
(8 or 16 ohms) 
EXT. SP JACK (8 or 16 ohms)

MOBILE INSTALLATION
Safety and operating convenience are the primary factors to consider when mounting any piece of
equipment in an automobile. Be sure that the transceiver controls may be easily reached by the
operator. Also be sure that connecting cables do not interfere with the operation of the brake, ac
celerator, etc.
POWER CONNECTION
The transceiver may be installed and used in any 12 volt DC negative or positive ground system
vehicle. Most newer U.S. and foreign-made cars and small trucks use a negative ground system while
some older cars and some newer large trucks may use a positive ground.
A negative ground system is generally identified by the (—) battery terminal being connected to the
vehicle motor block, but if you cannot determine the polarity system of your vehicle, it is suggested
that you contact your vehicle dealer for definite information.
NEGATIVE GROUND SYSTEM
Connect the red DC power cord from the transceiver to the positive or (+) battery terminal or other
convenient point and connect the black power cord to the negative or (—) battery terminal.
POSITIVE GROUND SYSTEM
In the case of a positive ground system connect the black DC power cord from the transceiver to
the negative or (—) battery terminal or other convenient point and connect the red power lead to the
chassis or vehicle frame or (+) battery terminal.
With regard to the connection of the power cords, it may be possible or desirable to connect the
(red lead for negative ground system) or (black lead for positive ground system) to the ignition switch
accessory terminal, so that the transceiver is automatically turned off when the ignition switch (key)
-- 7 —

is turned off.
Alternately, the power cord may be connected to an available terminal on the fuse block or even to
a point in the wiring harness. Care must be taken, however, to guard against a short circuit condition
so when in doubt, please contact your vehicle dealer for specific information for your vehicle.
MOBILE ANTENNA CONNECTION
A vertical whip antenna is best suited for mobile operation. A nondirectional antenna should be
used for best results in any case. The base-loaded whip antenna will normally provide effective com-
munication or for greater range and more reliable operation a full quarter-wave whip may be used.
Either of these antennas use the metal car body as a ground plane and the shield of the base lead
as well as the metal case of the transceiver should be grounded. A standard antenna connector
(type SO-239) is provided on the transceiver for easy connection to a standard PL-259 coax plug.
Following the antenna manufacturer's instructions carefully will insure proper operation.
Whatever the type of antenna selected, it is important that it be properly adjusted and matched and
the connecting transmission line be in good condition so as to avoid a high VSWR (voltage standing
wave ratio). A VSWR over 2.5 results in reduced radiated power and may cause instability and damage
to the final output stage of the transceiver.
BASE STATION OPERATION
When the 77-857 is used as a base station, any Citizens Band beam, dipole, ground plane or vertical
antenna may be used. A ground plane type antenna will provide good coverage, and since it is es-
sentially non-directional, it is ideal in base station to mobile operation. From base station to base
station or point-to-point operation a directional beam will give greater distance even under adverse
conditions. The range of the transceiver also depends on the height of the antenna so whenever pos-
sible, select the highest location within F.C.C. limits.
— 8 —

OPERATING INSTRUCTIONS
1.
Insert the MIC plug in the MIC connector.
2.
Make sure your Antenna is securely connected to the antenna connector.
3.
Turn the Power on and Adjust the VOLUME control for proper sound level.
4.
Temporarily turn and place the PA/SQUELCH control in slight clockwise position.
5.
Place the DELTA TUNE switch at center position.
6.
Place the EXT. CB-OFF switch in the OFF position.
7.
Place the Channel Selector switch to a desired channel.
8.
To transmit press the Push-to-Talk button on the microphone and to receive release the button.
IMPORTANT: Do not short circuit the antenna or do not try to transmit without an antenna
connected to the Antenna connector on the rear panel. This may cause damage
to the output power transistors. Transmit only after carefully checking the
installation of antenna connector and coaxial cable.
SPECIFICATIONS
Circuitry: 
3 ICs, 21 Transistors, 13 Diodes, 2 Zener Diodes, 1Vari-cap
Frequency Control:

PLL (Phase Lock Loop) Synthesizing System
Channels: 
40 channels all installed
Mode of operation:

AM