Hy-Gain 2795 User manual

hggaîn
SOLID STATE 120 CHANNEL
CITIZENS BAND 2-WAY RADIO

introduction
TotheOwners
Thank you for your confidence in selecting the model 2 95. We know you will find
your transceiver as exciting as it is practical. Only the highest quality components are
incorporated into your radio to assure reliability and maximum performance.
nstalling and operating the transceiver is not complicated, but the flexibility provided by
its many features may not be fully appreciated until a little time is spent becoming
familiär with its Controls and connections.
t will be to your advantage to save the packaging material — carton, filier, cushioning,
etc., they will prove valuable in preventing damage should you ever havé occasion to
transport or ship the unit.
1

installations
Installation
Plan the location of the transceiver and the microphone bracket before starting the
installation. Select a location that is convenient for operation and does not interfère
with the driver or passengers in the vehicle. The transceiver is usually mounted under-
neath the dash panel.
Mounting and Connections
The transceiver is supplied witn a universal mounting bracket. The transceiver is held in
the bracket by two bolts permitting adjustment to the most convenient angle. The
bracket must be mounted with the machine screws and the nuts supplied. The mounting
must be mechanically strong and also provide a good electrical contact to the chassis of
the vehicle. Proceed as follows to mount the transceiver.
1. After you hâve determined the most convenient location in your vehicle, hold the
transceiver with mounting bracket in the exact location desired. f nothing interfères
with mounting it in the desired location, remove the mounting bracket and use it as a
template to mark the location for the mounting bolts. Before drilling the holes, make
sure nothing interfères with the installation of the mounting bolts.
2. Connect the antenna cable plug to the standard réceptacle on the rear panel. Most
CB antennas are terminated with a type PL-259 plug and mate with the réceptacle of
the transceiver.
3. Connect tne power cord plug to the de power socket on rear panel.
4. Negative Ground Systems. Almost ail domestic mobiles and trucks are negative
grounded. The red lead at the end of the power cord connects to the positive pole of
the battery or electrical system, and the black lead connects to the negative pole of the
battery or suitable chassis ground.
5. Positive Ground Systems. n positive ground system mobile, connect the red lead
to the positive pole of the battery or suitable chassis ground, and the black lead to the
negative pole of the battery or electrical system.
6. Mount the microphone bracket to dashboard or other convenient location.
Ignition Noise Interférence
Use of the mobile transceiver at low level signal condition is normally limited by the
presence of electrical noises. The primary source of noise in an automobile installation
is from the generator and ignition system in the vehicle. Under most operating con
ditions, when signal level is adéquate, the background noise does not present a serious
problem. Also when extremely low level signais are being received the transceiver may be
operated with the vehicle engine off. The unit requires very low current and therefore
will not significantly discharge the battery. Even though your transceiver has a noise
blanker, in some installations ignition noise interférence may be high enough to make
good communications impossible. The electrical noise may corne from several sources.
Many possibilities exist and variations between vehicles require different solutions to
reduce the noises. Consult with your dealer or two-way radio technician for help in
locating and correcting the source of severe noise interférence.
2

control location
3

control functions
Controls
There are 9 Controls and 2 indicators on the front panel of your transceiver.
1. Volume/Squelch. These are concentrical Controls which do the following individual
adjustment:
Volume (inner knob). Turn clockwise to apply power to the radio and set the desired
listening level. Squelch (outer knob). This control is used to eut off oreliminate the re-
ceiver background noise in the absence of an incoming signal. For maximum receîve
sensitivity the control should be adjusted only to the point where the receiver back
ground noise is eliminated. Tum fu ly counterclockwise then slowly clockwise until the
receiver noise disappears. Any signal to be received must now be slightly higher than the
average received noise. Further clockwise rotation will increase the threshold level which
a signal must overcome to be heard. Only strong signais will be heard at a maximum
clockwise setting.
2. L/M/H (Band Switch). n this transceiver, 120 channels are divided into 3 groups of
40 channels, low 40, middle 40, and high 40. Set this selector to the position to which
the channel you desire belongs.
3. FM-LSB-USB-AM. This selects the mode of operation in either FM, AM, upperside-
band, or lower sideband. Transmissions in the FM, AM or sideband mode can only be
communicated to a station operating in the same mode.
4. Channel Selector. This switch selects one of 120 channels desired in conjunction
with the L/M/H Band switch. The selected channel will be digital ly displayed in the
window above.
Channels 1 through 40 are selected on this selector with the Hi-Lo Band switch placed
in the L position, channels 41 through 80 in the M position, while channels 81 through
120 in the Hi position.
5. Channel Indicator. This is an LED (light emitting diode) digital channel readout to
show the channel selected by the Channel selector.
6. RF Gain. Controls the réception sensitivity of the receiver. f a station received
sounds distorted, place this control in counterclockwise position where the S meter
pointer does not exceed S9.
. Clarifier. This provides fine tuning of the receiver. On regulär AM or FM réception,
this will permit adjustment to off-frequency transmissions. n the SSB (either USB, or
LSB) modes, this is used as a voice clarifier to adjust for clearer voice réception.
8. Meter. This shows the relative strength of an incoming signal from the antenna,
and transmit power output to the antenna. The meter is illuminated when power is on.
9. Tone Switch. Changes the receiving audio quality in two ways. Hi position empha-
sizes high tones, while Lo position emphasizes low tones.
10. NB (noise blanker) Switch. n the NB position, the RF noise blanker is activated.
The noise blanker is very effective in réduction of répétitive impulse noise such as ignition
interférence.
4

connections
Antenne
Only a properly matched antenna system will allow maximum power transfer from the
52 ohms transmission line to the radiating element. n mobile installations (cars, trucks,
etc.), an antenna system that is non-directional should be used.
A vertical polarized quarter-wave length whip antenna provides the most reliable opera
tion and greatest range. The shorter loaded type whip antennas are more attractive,
compact and adéquate for applications where the maximum possible distance is not re-
quired. Also the loaded whips do not present the problem of height imposed by fuit
quarter-wave length whip.
Mobile whip antennas utilize the metal body of the vehicle as a ground plane. When
mounted at a corner of the vehicle, they are slightly directional in the direction of the
body of the vehicle. For ail practical purposes, however, the radiation pattern is non-
directional. The slight directional characteristic will be observed only at extreme dis
tance. A standard antenna connector is provided on the transceiver for easy connection
to a standard cable terminations.
f the transceiver is not mounted on a metal surface, it is necessary to run a separate
ground wire from the unit to a good metal electrical ground in the vehicle.
Remote Speaker Connection
The external speaker jack (marked EXT SP) on the rear panel is used for remote re
celer monitoring. The external speaker should hâve 8 ohms impédance and be able
to handle at least 3 watts. When the external speaker is plugged in, the internai speaker
is automatically disconnected.
Sélective Call Connection
Special provision has been made for your transceiver to connect the optional sélective call
device. Ask your dealer for definite information. The sélective call unit is connected to
the Sell-Call jack on rear panel of the transceiver, which is normally occupied with a
prewired plug for normal operation. Do not remove the plug unless you are using a
sélective call unit.
5

Operation
Microphone and Transmit Switch
The receivenand transmitter are controlled by the transmit switch at the side of the
microphone (supplied). Depress the transmit switch and the transmitter is activated,
release the switch to receive. When transmitting hold the microphone 5 or 6 centimeters
from your lipsand speak in a normal voice. The transceiver will not be operative without
microphone connected to avoid unauthorized use.
Receive Operation
Connect the microphone to the radio and proceed as follows:
1. Rotate the Squelch control to 9 o'clock position.
2. Rotate the RF Gain control in fully clockwise position.
3. Temporarily, place the FM-LSB-USB-AM switch in AM position.
4. Turn unit on by rotating the Volume control clockwise and set for a comfortable
listening level.
5. Select a channel that is unoccupied by any other station and turn Squelch control
clockwise slowly until the hissing noise just disappears.
6. Adjust the FM-LSB-USB-AM switch and Clarifier for FM or SSB réception. The
knack of adjusting the Clarifier is very critical and important when listening to an SSB
signal. We suggest you spend some time becoming familiar with its use.
Transmit Operation
After you hâve checked that the channel you hâve chosen is elear proceed as follows.
1. Select a mode of émission — FM, LSB, USB or AM.
2. Again, make sure that the channel is elear.
3. Depress the transmit switch on the microphone.
4. Speak clearly with your mouth 5 to 6 cm from microphone.
5. To stop transmission and receive, release the transmit switch.
6. Allow a 2 to 3 second break betvveen the incoming signal and your transmission.
6

maintenance
Maintenance
The transceiver is specifically désignée! for the environment encountered in mobile in
stallation. The use of fully transistorized cireuitry containing very reliable Csand semi-
conductors resuit in high reliability and stability in both transmit and receive operation.
Should a failure occur, however, replace parts only with identical parts specified in the
schematic diagram (page 9).
f the performance described in the Receive Operation and Transmit Operation sélections
can not be obtained, review the instructions to ensure that the proper procedures are
followed. f a problem still exists, ask your dealer or qualified radio technician for
specific information.
7

technical information
General
Frequency Composition: PLL (phase locked loop) synthesization.
Frequency Range: 26.965 to 28.305 MHz.
Channels: 120
Frequency Tolérance: ±0.005%.
Emission: FM, AM, lower sideband, upper sideband.
Operating Température Range: —30°C to +50°C.
Operating Power Voltage: 13.8 volts (nominal 12 volts) de.
Receive Portion
Sensitivity at 10 dB S/N (AM): 0.7 microvolts*.
Sensitivity at 10 dB S/N (SSB): 0.2 microvolts*.
Sensitivity at 20 dB S/N (FM): 0.5 microvolts*.
IF Response at 6 dB down (AM): 6 kHz.
IF Response at 6 dB down (SSB): 2 kHz.
IF Response at 6 dB down (FM): 6 kHz
Audio Output Power for 8 ohms: 3 watts.
Clarification: ±800 Hz.
Squelch Range: 0.7 to 300 microvolts.
Intermediate Frequency (AM/FM): 10.695 MHz, 455 kHz.
Intermediate Frequency (SSB): 10.695 MHz.
* : with the RF Gain in fully clockwise position.
Transmit Portion
Harmonie Suppression: 60 dB down.
SSB Generation: Double balanced modulator with crystal'lattice filter.
Carrier Suppression (SSB): 40 dB down.
Opposite Sideband Suppression (SSB): 60 dB down.
RF Output Power at 13.8 volts dc (AM/FM): 7.5 watts.
RF Output Power at 13.8 volts dc (SSB): 12 watts PEP.
8

schematic diagram
9