Mirage BD-38-G User manual

MIRAGE BD-38-G Dual Band Amplifier
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MIRAGE BD-38-G
DUAL BAND POWER AMPLIFIER
INTRODUCTION:
The Mirage BD-38-G is a 80/60 watt dual band power amplifier for use with today's
dual band handie talkies operating in the 144/440MHz bands. We have succeeded in
the development of a cross-band full duplex function and have incorporated it into
this design. The BD-38-G is a remarkable and useful dual band power amplifier for
the discriminating Amateur Radio operator. This compact dual band power
amplifier has two independent GasFET pre-amp for VHF and UHF bands.
FEATURES:
• High output power
Up to 80 watts at 144MHz or up to 60 watts at 440MHz. Output is achieved
with 2 to 5 watts input.
• Input power from 0.25 to 5 watts.
With an input power of 5 watts maximum, the Mirage is compatible with most
modern hand-held tranceivers.
• Automatic Frequency selection and control circuit. This allows the amplifier to
have only one input connector and makes for a perfect match for today's dual
band radios and dual band antennas.
• Separate VHF and UHF Pre-Amps.
• Separate LED Indicators for VHF and UHF Pre-Amp usage.
• LED Bargraph Power Level indicator.
• Hi-SWR and Over Temperature Protection.
• Patch Cable included (BNC to PL-259).
• Input: 13.8 VDC at 15 amps.
• Size: 6.5” W x 2.5” H x 9” D
• One Year Warranty

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SPECIFICATIONS:
FREQUENCY: 144 TO 148MHz / 430 TO 450MHz
RF INPUT: 0.25 - 5 watts
RF OUTPUT: Up to 60 watts at 440MHz and up to 80 watts at
144MHz
DUTY CYCLE: INTERMITTENT (ICAS)
MODES: F3 (FM)
KEYING: AUTOMATIC SENSING
SUPPLY VOLTAGE: 13.8 Vdc
RF CONNECTORS: TWO (2) SO-239 UHF
SUPPLY CURRENT: 15 AMPS TYPICAL
FUSE: 8 AMP, FAST BLOW
INPUT/OUTPUT IMPEDANCE: 50 OHMS

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EXPLANATION OF FEATURES:
Front Panel
• POWER ON Switch
This switch turns on the power to the amplifier. When the power switch is
engaged the amplifier is ready to amplify any signal of the proper frequency
applied to its input.
• VHF Pre-Amp Switch
This switch turns the pre-amp on for the VHF (144~148MHz) band.
• Pre-Amp VHF LED
This LED indicates status of the VHF (144~148MHz) band pre-amp. When the
LED is ON, the pre-amp is active.
• UHF Pre-Amp Switch
This switch turns the pre-amp on for the UHF (430 - 450MHz) band.
• Pre-Amp UHF LED
This LED indicates status of the UHF (430~450MHz) band pre-amp. When the
LED is ON, the pre-amp is active.
• SWR LED
This LED will turn ON if the SWR of the antenna used is too high. When this
light is on, there will be no amplified output from the BD-38-G due to the
protection circuit inside the amplifier.
Back Panel
• ANT (RF OUTPUT)
The coax from your antenna is connected to this port.
• RADIO (RF INPUT)
The coax from your radio or exciter is connected to this port.
• DC PWR (13.8V)
This port has two wires. The Red wire is for positive and incorporates a FUSE
holder. The Black wire is for negative. The Mirage BD-38-G amplifier
requires a source of 13.8 Vdc at 15 amps.

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INSTALLATION AND OPERATION:
The Mirage BD-38-G may be mounted using the bracket (not 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 heat-sink to any surrounding enclosure and an unobstructed flow from the
front to the back of the heat sink. Do not operate the amplifier in places where it will
be exposed to direct sunlight or a nearby heat source such as heaters, radiator, etc.
+CAUTION: With extended use, the heat sink becomes VERY HOT!
If it is necessary to extend the DC power leads, use wire of the same gauge in order
to avoid a voltage drop on your power leads. Be careful that the DC power supplied
is no higher than 15 Volts or damage may result. A source voltage of 13.8 Vdc and
16 amps is recommended and should be used whenever available. Some automobiles
will generate a high current surge when started. It is recommended that the amplifier
be placed in the OFF position when starting your vehicle.
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. If used in a mobile installation, choose a good mobile antenna which
will withstand the power of this amplifier. Be sure to check the SWR for any
degrading once the antenna has been heated by a few minutes of operation. An
antenna with a rating of 100 watts is recommended.
Never connect the "rubber duck" antenna supplied with your tranceiver directly to the
antenna connector of the amplifier unit by use of a SO-239 to BNC converting unit,
or by any other means; It may cause damage to both the amplifier and the "rubber
duck."
When utilizing a mono band antenna, check the transmitting frequency of your radio
and be sure that it is matched to the type of antenna you are using prior to operation.
Furthermore, when inserting coaxial switches to either or both input or output of the
power amplifier in order to operate two sets of tranceivers and antennas of which the
frequencies differ, be sure to carefully check switch positions.

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A typical connection of this amplifier with duplex type dual band tranceiver and a
dual band antenna is shown in Figure 1. If connection of this amplifier is made with
either two tranceivers or two antennas, please refer to Figures 2 or 3.

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During 144MHz / 440MHz crossband full duplex operation, there may be some
minor interferences such as noise on certain frequencies (depending on the
combination of Transmit / Receive frequencies selected). Select TX/RX frequencies
which show no interferences and/or trouble especially with a 144MHz band
transmission and a 440MHz reception. Select frequencies that are not mutually
harmonic.
With some regulated DC power supplies, the output voltage may rise to an abnormal
level, resulting from malfunctions due to RF signal intrusion. Therefore, use a power
supply with sufficient current capacity as well as with good protection against RF
intrusion. If the power supply malfunctions, discontinue operation by turning the
power switch off.
If the amplifiers power cables are connected in reverse polarity, the cables could
sustain damage, especially when your source is a battery. Be sure to check the
polarity before connection!
After confirmation of proper connections, etc., turn the power switch ON. Transmit
either a 144MHz or a 440MHz signal to the antenna and confirm the SWR is at the
proper level. Switch the band of operation opposite of the one selected above and
transmit again to confirm that the amplifier has detected the proper band and the
SWR is at the proper level.
To operate the pre-amp, simply turn the switch corresponding to the proper band to
the ON position. The LED for this band will light up and indicate that the pre-amp is
in use.
TROUBLESHOOTING:
The Mirage BD-38-G is designed for long, trouble-free performance and should not
require extensive troubleshooting in the field. If difficulty is encountered, check the
following before assuming the amplifier has a malfunction:
1. Loose antenna or power supply connections
2. VSWR of the antenna system
3. Coaxial cables from radio to amplifier, and amplifier to antenna
4. Output voltage of power supply
5. Power output of radio
6. Improper fuse rating

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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 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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ONE YEAR LIMITED WARRANTY
Any Mirage Communications product found to be defective in materials or workmanship will be repaired
or replaced (at Mirage’s option) for a period of one year from the date of original purchase.
During the warranty period Mirage Communications will provide, free of charge, both parts and labor
necessary to correct defects in material or workmanship.
• To obtain such warranty service, the original purchaser must:
(1) Provide “proof of purchase”
(2) Ship the product in its original container or equivalent, fully insured and shipping
charges prepaid, to Mirage, as addressed below.
(3) Mirage agrees to repair without charge to the original owner any defective product
under warrantee provided the product is returned with postage prepaid to Mirage with a
personal check, cashiers check, or money order for $10.00 covering postage and handling.
• All internal adjustments are factory set for best performance consistent with reliable operation.
Changing internal adjustments may void this warranty.
• Improper maintenance or repair may also void this one year warranty. We recommend that units
requiring repair during the warranty period be returned to the factory.
• This unit was not designed for repeater operation, and its use in such service is at your own risk.
• Mirage assumes no responsibility for any item connected to or used in conjunction with this
product.
• The foregoing constitutes Mirage’s entire obligation with respect to this product and the original
purchaser and any user or owner shall have no remedy and no claim for incidental or consequential
damages.
• All Mirage products to be serviced, in-warranty or out-of-warranty, should be shipped, freight paid
to: Mirage, 921 Louisville Road, Starkville, MS 39759, USA. Product must be accompanied by a
letter describing the problem in detail. Be sure to include YOUR NAME, ADDRESS, AND
TELEPHONE NUMBER!
• This warranty gives specific legal rights and you may also have other rights which vary from state to
state.
WARNING: This unit should not be operated with the cover removed. The cover confines RF radiation.
The harmonic filters contained in the circuit will not suppress direct radiation that may result if the cover
is removed.