The DX 44HP Manual
DX 44HP
10 Meter Amateur Mobile Transceiver
OWNER’S MANUAL
Printed In Taiwan
P/N:A412308COA
TABLE OF CONTENTS
Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications
Page
2
Installation
GENERAL
Frequency Range
Frequency Control
Frequency Tolerance
Frequency Stability
Operating Temperature
Range
Microphone
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
Mounting the Radio . . . . . . . . . . . . . . . . . . . . . . .
4
Ignition Noise Interference . . . . . . . . . . . . . . . . . . . . . .
5
Input Voltage
Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
Current
Tuning the Antenna for Optimum SWR . . . . . . . . . . . .
6
External Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
Operation
Size
Weight
Antenna Connector
Meter
Control Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
A. Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
TRANSMITTER
Power output
B. Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
Modulation
Press-To-Talk Microphone . . . . . . . . . . . . . . . . . . . . . .
11
Operating Procedure to Receive . . . . . . . . . . . . . . . . . .
11
Operating Procedure to Transmit . . . . . . . . . . . . . . . . .
11
Alternate Microphones and Installation . . . . . . . . . . . .
12
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .
18
-1-
Spurious Emissions
Frequency Response
Output Impedance
Output Indicators
28.015 to 28.465 MHz
Phase Lock Loop (PLL) synthesizer.
0.005%
0.001%
-20 C to +50 C.
Plug-in dynamic; with push-to-talk switch and
coiled cord.
13.8V DC nominal, 15.9V max, 11.7V min.
(Positive or negative ground).
Transmit: AM/FM Hi Power _ 10A.
Receiver: Squelched, _ 0.3A.
Maximum Audio output, _ 0.7A.
2-3/8” (H) x 7-7/8” (W) x 9-1/4” (D).
5.0 1bs.
UHF, SO239
Illuminated; indicates relative output power,
received signal strength and SWR.
AM/FM – Variable; 10 watt maximum
Modulation: AM. Variable capacitance 90%±
10%
Frequency Modulation: FM. 4KHz ±1KHz
50 dB
AM and FM: 300 to 2500 Hz.
50 ohms, unbalanced
Meter- shows relative RF output power.
Transmit LED glows red when transmitter is
in operation.
-2-
Installation
RECEIVER
Sensitivity
Selectivity
Image Rejection
IF Frequency
Adjacent-Channel
Rejection
RF Gain Control
Automatic Gain Control
(AGC)
Squelch
ANL
Noise Blanker
Audio Output Power
Frequency Response
Built-in Speaker
External Speaker (Not
Supplied)
AM: 0.5 V for 10 dB (S+N)/N at greater than
½ -watt of audio output.
FM: 1.0 V for 20 dB (S+N)/N at greater than
½ -watt of audio output.
AM/FM: 6 dB @ 3 KHz, 50 dB @ 9 KHz.
More than 65 dB.
AM/FM: 10.695 MHz 1st IF, 455 KHz 2nd
IF
60 dB AM
45 dB adjustable for optimum signal
reception.
Less than 10 dB change in audio output for
inputs from 10 to 1,000mV.
Adjustable; threshold less than 0.5 V.
Switchable
RF type
4 watts into 8 ohms.
300 to 2500 Hz.
8 ohms, round.
8 ohms; disables internal speaker when
connected.
-3-
LOCATION
Plan the location of the transceiver and microphone bracket before starting the
installation. Select a location that is convenient for operation and does not interfere
with the driver or passengers in the vehicles. In automobiles, the transceiver is
usually mounted below the dash panel, with the microphone bracket beside it.
MOUNTING THE RADIO
Your transceiver is supplied with a universal mounting bracket. When
mounting the bracket and radio to your car, make sure it is mechanically strong.
Also provide a good electrical connection to the chassis of the vehicle. Proceed as
follows to mount the transceiver:
1.
After you have determined the most convenient location in your vehicle, hold
the transceiver with mounting bracket in the exact location desired. If nothing
will interfere with mounting it in the desired position, remove the mounting
bolts. Before drilling the holes, make sure nothing will interfere with the
installation of the mounting bolts.
2.
Connect the antenna coax connector to the standard antenna connector on the
rear panel of the radio. Most antennas are terminated with a type PL-259
connector.
3.
Connect the red DC power input wire (with the fuse) to +13.8V DC. This wire
extends from the rear panel. In automatic installation, +13.8V DC is usually
obtained from the accessory contact on the ignition switch. This prevents the
set being left on accidentally when the driver leaves the car and also permits
operating the unit without the engine running. Locate the accessory contact on
most ignition switches by tracing the power wire from the AM broadcast
receiver in the car.
4.
Connect the black lead to –13.8V DC. This is usually the chassis of the car.
Any convenient location with good electrical contact (remove paint) may be
used.
5.
Mount the microphone bracket on the right side of the transceiver or near the
transceiver, using two screws supplied. When mounting in an automobile,
place the bracket under the dash so the microphone is readily accessible.
--4-
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 generator 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 off. The unit requires very
little current and therefore will not significantly discharge the vehicle battery.
Even though the transceiver has ANL and NB controls, in same installations
ignition interference may be high enough to make good communications
impossible. The electrical noise may come from several sources. Many possibilities
exist and variations between vehicles require different solutions to reduce the noise.
ANTENNA
A vertically polarized, quarter-wavelength whip antenna provides the most
reliable operation and greatest range. Shorter, loaded-type whip antennas are more
attractive, compact and adequate for applications where the maximum possible
distance is not required. Also, the loaded whips do not present the problems of
height imposed by a full quarter-wavelength 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 all practical purpose, however, the
radiation pattern is nondirectional. The slight directional characteristic will be
observed only at extreme distance. A standard antenna connector (type SO239) is
provided on the transceiver for easy connection to a standard PL 259 cable
termination.
If 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.
When installed in a boat, the transceiver will not operate at maximum efficiency
without a ground plate, unless the vessel has a steel hull.
Before installing the transceiver in a boat, consult your dealer for information
regarding an adequate grounding system and prevention of electrolysis between
fittings in the hull and water.
-5-
NOTE
THE PROPER SETTING IS ACHIEVED WHEN THE SWR IS
1.5 OR BELOW, AND WHEN IT HAS THE SIMILAR
READING FOR CHANNELS 1 AND 40.
If you are having difficulties in adjusting your antenna, check the following:
A. All doors must be closed when adjusting the antenna.
B. Make sure the antenna base is grounded.
C. Check your coaxial cable routing (it may be pinched when routed into the
car).
D. Try a different location on your car (keeping in mind the radiation pattern
you wish)
E. Is the antenna perfectly vertical?
F.
Try a different location in your neighborhood. Stay away from large
metal objects when adjusting (metal telephone or light posts, fences, etc.).
NOTE
The transceiver will operate into an SWR of 2 to 1 indefinitely
and sustain an SWR of 20:1 for a maximum of 5 minutes at rated
operating conditions.
EXTERNAL SPEAKER
The external speaker jack (EXT.SPK) on the rear panel is used for remote
receiver monitoring. The external speaker should have 8 ohms impedance and be
able to handle at least 4 watts. When the external speaker is plugged in, the internal
speaker is disconnected.
-6-
Operation
5.
RF GAIN CONTROL: (outer dual concentric). Use to reduce the gain of
the received signal under strong signal conditions.
CONTROL FUNCTIONS
There are fifteen controls and six indicators on the front panel of your
transceiver.
6.
MIC GAIN CONTROL: (inner dual concentric). Adjust the microphone
gain in transmit and PA modes. This controls the gain to the extent that full
talk power is available several inches away from the microphone.
7.
DIMMER CONTROL: Controls the brightness of the meter lamp, channel
display digits, +10KHz LED, RB LED and the RX/TX LED. It does not
control the brightness of the SWR alert LED. That LED is always at maximum
brightness.
8.
RF POWER CONTROL: This control allows the user to adjust RF power
output.
9.
CHANNEL SELECTOR: This switch selects any one of the forty channels
desired. The selected channel number is on the LED readout directly above the
Channel Selector knob.
FRONT PANEL
MOD LAMP: When switched on, this Modulation indicator will illuminate as
you speak into the microphone. When you speak louder, it appears bright
because it is on nearly 100 percent of the time and when you speak softer, it
appears dimmer because it is flickering on and off. It does not glow at all when
there is no modulation. This lamp operates in all modes.
10. RX/TX LED: This LED lights red to indicate the unit is in the transmit mode.
It lights blue to indicate the unit is in the receive mode.
2.
MICROPHONE JACK: Used to connect microphone for voice source.
12. BAND SELECTOR: This switch is used to select the band.
3.
SQUELCH CONTROL (outer dual concentric): This control is used to cut
off or eliminate receiver background noise in the absence of an incoming
signal. For maximum receiver sensitivity it is desired that the control be
adjusted only to the point where the receiver background noise or ambient
background noise is eliminated. Turn fully counterclockwise then slowly
clockwise until the receiver noise disappears. Any signal to be received must
now be slightly stronger than the average received noise. Further clockwise
rotation will increase the threshold level which a signal must overcome in
order to be heard. Only strong signals will be heard at a maximum clockwise
setting.
13. TIME CONTROL: (outer dual concentric). This control is used to set the
interval of the echo effect.
1.
4.
OFF/ON/VOLUME CONTROL (inner dual concentric): Turn clockwise to
apply power to the unit and to set the desired listening level. During normal
operation, the VOLUME control is used to adjust the output level obtained
either at the transceiver speaker or the external speaker, if used.
-7-
11. METER: Indicates received signal strength, transmitter output power and
SWR.
14. ECHO CONTROL: (inner dual concentric). This control is used to set the
amount of the echo effect.
15. SWR/OFF/R.B. SWITCH: This switch controls the function of the meter
during the transmit mode. In the “SWR” position, the meter indicates the
Standing Wave Ratio (SWR) of your antenna (accurate at maximum power
output). There are no adjustments because the SWR circuit in this radio
calibrates itself automatically. When in the RB position, the radio transmits an
audio tone at the end of your transmission to indicate that transmission has
ended. As a courtesy to others, use the Roger Beep only when necessary. The
SWR function and the RB function cannot be used at the same time.
- 8-
16. NB/ANL/OFF SWITCH: In the ANL position, the Automatic Noise Limiter
circuit is activated. In the NB/ANL position, the RF Noise Blanker is also
activated. This Noise Blanker is very effective for repetitive impulse noise
such as ignition interference. Both ANL and NB are off when this switch is in
“OFF”.
REAR PANEL
17. MODE (PA/FM/AM) SWITCH: This switch is used to select PA, FM, or
AM mode of operation. When you set to PA position, the transceiver acts as a
public address amplifier. Before operating PA, you must first connect an
external PA speaker (8 ohm, 4-watt) to the PA Speaker jack on the unit rear
panel.
18. MOD LAMP/OFF/+10KHz SWITCH: When in the MOD LAMP position,
the Mod Lamp circuit is activated. When the switch is in the +10KHz position,
the frequency is shifted up 10KHz. When this switch is in the OFF position,
the Mod Lamp does not function and the frequency is not shifted up.
19. TALKBACK/ECHO/OFF: When this switch is in the TALKBACK position,
it is used to monitor your own voice in the radio speaker. For example, you
could use this feature to compare different microphones. When in the ECHO
position, it will add an echo effect to your voice. Both Echo and Talkback are
off when this switch is in the OFF position.
20. +10KHz LED: This LED lights green when the frequency is shifted up 10KHz.
1. ANTENNA. Accepts 50 ohm coaxial cable with a type PL-259 connected.
21. CHANNEL INDICATOR: Numbered LED indicates the selected channel
you wish to operate on.
2. POWER. Accepts 13.8V DC power cable with built-in 10 amp fuse.
22. RB/SWR LED: This LED lights red to indicate an SWR that is higher than
around 3:1. It is not an exact indicator of a 3:1 SWR. When it lights red, please
check your SWR using the built in SWR circuit. This LED lights blue to
indicate the Roger Beep circuit is on. If the Roger Beep circuit is on and the
SWR is high, during transmit both the blue and red segments of this LED will
light. The color will appear to be purple.
-9-
3. F.C. This socket is for optional FREQUENCY COUNTER model FC-347. The
FC347 will indicate the transmit and receive frequency.
4. PA. SP. Used to connect a PA speaker (8 ohm 4W) for PA operation. Before
operating PA you must first connect a PA speaker to this jack.
5. EXT SP. Accepts 4 to 8 ohms, 5-watt external speaker to be connected. When
external speaker is connected to this jack, the built-in speaker is automatically
disconnected..
-10-
PRESS-TO-TALK MICROPHONE
ALTERNATE MICROPHONES AND INSTALLATION
The receiver and transmitter are controlled by the press-to-talk switch on the
microphone. Press the switch and the transmitter is activated, release switch to
receive. When transmitting, hold the microphone two inches from the mouth and
speak clearly in a normal “voice”. The radios come complete with low-impedance
(500 ohm) dynamic microphone. For installation instruction on other microphones,
see next section, “ALTERNATE MICROPHONES AND INSTALLATION”.
For best results, the user should select a low-impedance dynamic type
microphone or a transistorized microphone. Transistorized type microphones have
a low output impedance characteristic. The microphones must be provided with a
four-lead cable. The audio conductor and its shielded lead comprise two of the
leads. The fourth lead is for receive control, and the third is for transmit control.
The microphone should provide the functions shown in schematic below.
OPERATING PROCEDURE TO RECEIVE
1.
Be sure that power source, microphone and antenna are connected to the
proper connectors before going to the next step.
2.
Turn unit on by tuning VOL control clockwise on your transceiver.
3.
Set the VOLUME for a comfortable listening level.
4.
Set the MODE switch to the desire mode.
5.
Listen to the background noise from the speaker. Turn the SQUELCH control
slowly clockwise until the noise JUST disappears (no signal should be
present). Leave the control at this setting. The SQUELCH is now properly
adjusted. The receive will remain quiet until a signal is actually received. Do
not advance the control too far, or some of the weaker signals will not be heard.
6.
Set CHANNEL selector switch to the desired channel.
7.
Set the RF gain control fully clockwise for maximum RF gain.
4 WIRE MIC CABLE
Pin Number
Mic Cable Lead
1
Audio shield
2
Audio Lead
3
Transmit control
4
Receive Control
OPERATING PROCEDURE TO TRANSMIT
Fig. 1 Your transceiver microphone schematic.
1.
Select the desired channel of transmission.
2.
Set the MIC GAIN control fully clockwise.
If the microphone to be used is provided with pre-cut leads, they must be revised as
follows.
3.
If the channel is clear, depress the push-to-talk switch on the microphone and
speak in a normal voice.
1.
Cut leads so that they extend 7/16” beyond the plastic insulating jacket of the
microphone cable.
2.
All leads should be cut to the same length. Strip the ends of each wire 1/8” and
tin the exposed wire.
Before beginning the actual wiring read carefully, the circuit and wiring
information provided with the microphone you select. Use the minimum head
required in soldering the connections. Keep the exposed wire lengths to a minimum
to avoid shorting when the microphone plug is reassembled.
- 11 -
- 12 -
Fig. 3 Microphone plug pin numbers viewed from rear of pin receptacle.
Be sure that the housing and the knurled ring of Fig. 2 are pushed back onto
the microphone cable before starting to solder. If the washer is not captive to
the pin receptacle body, make sure that it is placed on the threaded portion of
the pin receptacle body before soldering.
If the microphone jack is used to hold the pin receptacle during the soldering
operation, best results are obtained when the connections to pins 1 and 3 are
made first and then the connections to pins 2 and 4. Use a minimum amount
of solder and be careful to prevent excessive solder accumulation on pins,
which could cause a short between the pin and the microphone plug housing.
6.
When all soldering connections to the pins of the microphone plug are
complete, push the knurled ring and the housing forward and screw the
housing onto the threaded portion of the pin receptacle body. Note the location
of the screw clearance hole in the plug housing with respect to the threaded
hole in the pin receptacle body. When the housing is completely threaded into
the pin receptacle body, a final fraction of a turn either clockwise or
counterclockwise may be required to align the screw hole with the threaded
hole in the pin receptacle body. When these are aligned, the retaining screw is
then screwed into the place to secure the housing to the pin receptacle body.
7.
The two cable clamp retainer screws should now be tightened to secure the
housing to the microphone cord. If the cutting directions have been carefully
followed, the cable clamp should secure to the insulating jacket of the
microphone cable.
8.
Upon completion of the microphone plug wiring, connect and secure the
microphone plug in the transceiver.
Fig. 2 Microphone plug wiring
1.
Remove the retaining screw
2.
Unscrew the housing from the pin receptacle body
3.
Loosen the two cable clamp retainer screws.
4.
Feed the microphone cable through the housing, knurled ring and washer as
shown Fig. 2.
5.
The wires must now be soldered to the pins as indicated in the above wiring
tables. If a vise or clamping tool is available it should be used to hold the pin
receptacle body during the soldering operation, so that both hands are free to
perform the soldering. If a vise or clamping tool is not available, the pin
receptacle body can be held in a stationary position by inserting it into the
microphone jack of the front panel. The numbers of the pins of the microphone
plug are shown in Fig. 3, as viewed from the back of the plug. Before soldering
the wire to the pins, pre-tin the wire receptacle of each pin of the plug.
- 13 -
-14-
MEMO
MEMO
-15-
-16-
MEMO
WARRANTY
This radio is covered by a three year
limited parts and labor warranty.

“Limited” means that we will repair problems caused by factory defects or
normal use at no charge.

Before returning a radio to us for warranty service, please call our Service
Department for a Repair Authorization Number (RAN). This RAN must be
written below your return address on the outside of the shipping box. Boxes
which arrive without an RAN will be refused, and the shipping company will
return the unopened box to you. Be sure to have a pen and paper ready along
with the serial number of your radio before calling. We will give you the RAN
and our shipping address over the phone. The telephone number of the Service
Department is (760) 480-8800, and we suggest calling between 10:00 AM and
4:00 PM Pacific Time.

Please include a note with a detailed description of the symptoms. This is
important because it will help the technician who works on your radio to locate
your problem. Intermittent problems are easily overlooked, so be sure to give
as much detail as possible in your note. Also, please include your telephone
number in case our technicians have any additional questions.

Do not send your bracket, power cord or microphone unless we ask for these
items during our telephone conversation.

You are responsible for getting the radio safely to us. (We suggest using
United Parcel Service.) You must pay to ship the radio to us, and we will pay
to ship the radio back to you. Since we use UPS and they do not ship to Post
Offices boxes, please provide us with a street address for the return of your
radio.

We will repair and return your radio as soon as we can. We appreciate your
choosing a Galaxy radio and we want you to be on the air as much as possible!
Be sure to visit our web site at
www.GalaxyRadios.com
-17-
-18-
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