C-22-G Instruction Manual R. F. Amplifier
C-22-G
R.F. AMPLIFIER
The Mirage C-22-G is the next generation of Power Amplifiers for 220 - 225 MHz. New
features make it the most useful and versatile amplifier available. Features include
automatic power shut-down circuitry for protection against excessive R.F. power input.
A newly designed GaAsFET receive pre-amp provides high gain and low noise
amplification for weak signal applications. The pre-amp incl udes a selectable attenuator
to reduce signal output level. This is useful in preventing Receiver Overload and
subsequent Intermodulation Distortion caused by strong signals. The Mirage C-22-G is
capable of FM, SSB, and CW operational modes.
SPECIFICATIONS
Frequency Range.......................................................220 - 225 MHz
R.F. Input Power (Drive)...........................................0.4 - 4 Watts (5 Watts max.)
R.F. Output Power..................................................... 20 Watts with 2 Watts drive
Duty Cycle.................................................................Intermittent (ICAS)
Modes........................................................................ FM, SSB, CW
Receive Pre-amp ....................................................... GaAsFET, Gain 21/15 dB-Nominal.
Noise figures less than 0.6 dB. 1 dB
compression point greater than -13
dBm input (Nominal)
R.F. Input Power Shutdown Point............................. In excess of 5 Watts nominal
Keying.......................................................................Automatic (R.F. sensing)
Input/Output Impedance............................................ 50 Ohms
R.F. Connectors......................................................... SO-239 (UHF)
Supply Voltage.......................................................... 13.8 VDC (for full R.F. power
output)
Supply Current .......................................................... 4 Amps (nominal)
Fuse ...........................................................................Low voltage, fast blow. 7-1/2 Amps
Physical Dimensions.................................................3-1/2 x 2 x 7 inches
Weight.......................................................................1 1/4 pounds
INSTALLATION
The Mirage C-22-G may be mounted using the brackets supplied or simply placed in a
convenient operating position. In either case, there must be adequate ventilation for the
finned heat-sink. This generally means at least 1 inch clearance from the sink to any
surrounding enclosure and an unobstructed flow from the front to the back of the sink.
CAUTION: With extended use the heat sink becomes very hot. If it is necessary to
extend the D.C. power leads, use wire of the same gauge in order to avoid a voltage drop
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C-22-G Instruction Manual R. F. Amplifier
on your power leads. Use a minimum length of good quality 50 Ohm cable between the
radio and the amplifier. The antenna system should have a VSWR of 1.5:1 or better for
best performance. The receiving pre-amp gain is set to the high value at the factory. To
switch to minimum gain move the DIP switch, which is located behind the left side cover
where there is a 1/4" hole, to the "up" position. If desired, the transmit relay hold-in
(hang-time) may be adjusted by adjusting the potentiometer located behind the hole on
the right side of the amplifier.
FRONT PANEL SWITCHES/LED'S
POWER ON/OFF SWITCH .........................Turns the D.C. power ON or OFF.
SSB/FM SWITCH.........................................Selects relay time delay for the mode
of operation. The relay drop time is
lengthened for the SSB mode of
operation.
PRE-AMP ON/OFF SWITCH...................... Turns Pre-amp power ON or OFF.
POWER LED................................................Indicates that D.C. power is applied.
PRE-AMP LED............................................. Indicates that the pre-amp is turned
ON.
OVERLOAD LED........................................ Indicates amplifier shutdown due to
excessive R.F. drive power. Reset
by turning OFF then ON.
REAR PANEL CONNECTORS
RADIO (SO-239).......................................... R.F. input from radio.
ANT (SO-239)...............................................R.F. output to antenna.
INTERNAL ADJUSTMENTS
SSB DELAY................................................. This allows the R.F. relay "hang-
time" or delay to be adjusted to the
time desired.
PRE-AMP ATTENUATOR SWITCH .........Sets the pre-amp gain to full or
reduced value.
INPUT VSWR AND OUTPUT POWER..... These adjustments are made at the
factory and should not require field
adjustment.
PRE-AMP TUNING..................................... These adjustments are also made at
the factory for best gain and noise
figure performance. They should not
require field adjustment.
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C-22-G Instruction Manual R. F. Amplifier
TROUBLESHOOTING
The Mirage C-22-G is designed for long, trouble-free performance and should not require
extensive troubleshooting in the field. NOTE: In the event of automatic power shut-
down, the amplifier must be turn ed off , and the cause of shut-down determined and
removed. In case of difficulty check the following before assuming amplifier
malfunction:
a. Loose antenna or power supply connections.
b. VSWR of antenna system.
c. Coaxial cables from radio to amplifier, and amplifier to antenna.
d. Output voltage of power supply.
e. Power output of radio.
f. Improper fuse rating.
WARNING:
This unit should not be op erated w ith the cover removed Th e cover
confines R.F. radiation, including harmonics, to the inside of the
case. Operation of the unit wi thout the cover could resu lt in direct
harmonic radiation. The harmonic filters contained in the circu it
will not suppress direct radiation.
IMPORTANT REMINDER
All MIRAGE amplifiers manufactured for amateur radio - with the exception of
repeater amplifiers - are rated as ICAS - Intermittent Commercial and Amateur
Service. This generally means 5 minute duty cycles, i.e. 5 minutes transmitting, 5
minutes receiving.
Although all of our units, except the hand helds, have thermal protection, continued
use where this cut out occurs can damage transistors.
TECHNICAL ASSISTANCE
If you have any problem with this unit first check the appropriate section of this manual.
If the manual does not reference your problem or your problem is not solved by reading
the manual you may call MIRAGE at 601-323-8287. You will be best helped if you have
your unit, manual and all information on your station handy so you can answer any
questions the technicians may ask.
You can also send questions by mail to MIRAGE, 921 HWY 25 South, Starkville, MS
39759 or by Fax to 601-323-6551. Send a complete description of your problem, an
explanation of exactly how you are using your unit, and a complete description of your
station.
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