Midland BR777 Alignment Procedure
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1. REFERENCE TEST EQUIPMENT
A. HP8921A Cell site test set or HP8920A, B Communication Test Set with Spectrum
Analyzer option.
B. Fluke 187 Digital Voltmeter
C. HP E3615A Power supply
2. TEST POINT
A. ANTENNA
B. VCO reference voltage
C. RX audio output
D. TX Mic. Input
E. Battery Vcc
F. Up Key
G. Down Key
H. Function Key
I. Monitor Key
J. PTT Key
K. CALL Key
Note. : All key can be activated when connect with ground except Power key.
3. VCO ALIGNMENT
A. Set unit to Channel 1 and connect a voltmeter to TP1 (VCO PD).
B. Press & hold PTT.
C. Extend L303 until the voltmeter reads 1.0V.
D. Release PTT button so units is in receiving mode and monitor the voltage on TP1. The
voltage should be in the range 1.0Vds +/-0.5V
E. Set unit to channel 4.
F. Press & hold the PTT switch and observe the voltage on TP4. The voltage should be 1 –
2.4 Vdc.
G. Release PTT and observe the voltage on TP1. The voltage should read between 1.0 – 2.4
Vdc.
Note : VCO shield-can should be soldered after VCO alignment is finished.
4. TRANSMITTER FREQUENCY ALIGNMENT
A. Press & hold the PTT button.
B. Align CT201 trimmer capacitor such that the output frequency is equal to the channel
frequency with a maximum error of +/- 200 Hz. CT201 is located on the left side of VCO
shield can.
BR777
ALIGNMENT PROCEDURE
: Test point is not prepared. Use antenna contact with
ANTENNA_GND_T(antenna ground).
: Test point 1 is prepared.
: Test point SPKOUT is prepared.
: Test point MICIN is prepared.
: Test point BAT is prepared.
: Test point UP is prepared.
: Test point DW is prepared.
: Test point Menu is prepared.
: Test point SCAN is prepared.
: Test point PTT is prepared.
: Test point CALL is prepared.
Page 1

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Summary of Contents for Midland BR777

  • Page 1 BR777 ALIGNMENT PROCEDURE 1. REFERENCE TEST EQUIPMENT A. HP8921A Cell site test set or HP8920A, B Communication Test Set with Spectrum Analyzer option. B. Fluke 187 Digital Voltmeter C. HP E3615A Power supply 2. TEST POINT A. ANTENNA : Test point is not prepared. Use antenna contact with ANTENNA_GND_T(antenna ground).
  • Page 2: Alignment Procedure

    BR777 ALIGNMENT PROCEDURE 5. TRANSMITTER OUTPUT POWER CONFIRMATION A. Set unit to channel 1 and power Hi mode. B. Press & hold the PTT button. C. Transmit power should normally be between 1.0W to 1.5W. 6. TRANSMITTER DEVIATION ALIGNMENT A. Connect an audio generator (600 ohms) to the ear jack. The audio frequency should be set at 1KHz with a level of 200mV RMS.
  • Page 3: Frequencies Table

    BR777 ALIGNMENT PROCEDURE FREQUENCIES TABLE Display # Freq. MHz Display # Freq. MHz 464.5000 462.9125 464.5500 464.4875 467.7625 464.5125 467.8125 464.5375 467.8500 464.5625 467.8750 466.0375 467.9000 466.0625 467.9250 466.0875 461.0375 466.1125 461.0625 466.1375 461.0875 466.1625 461.1125 466.1875 461.1375 466.2125 461.1625 466.2375...
  • Page 4 BR777 LABORATORY TESTING PROCEDURES UNIT TEST - (UNIT ASSEMBLED) TEST PREPARATION 1) Install 1 Lithium Ion battery. Left bottom terminal is the system plus polarity Right bottom terminal is the system minus polarity. 2) Press the power button. SYSTEM TEST 1) Radiated Transmit and Receive performance may be observed.
  • Page 5 BR777 LABORATORY TESTING PROCEDURES SPECIFIC TEST METHODS AND GUIDANCE Modulation Characteristics – (paragraph 2.1047(a) of the Rules) FOR TX AUDIO FILTER RESPONSE 1. Connect audio generator with 10uF coupling capacitor to microphone input jack. Press PTT button. 2. Connect RF output with modulation meter. (Filters of modulation meter should be set to a 50Hz to 15KHz.)
  • Page 6: Production Specification

    BR777 PRODUCTION SPECIFICATION 1. GENERAL SPECIFICATION Items Specifications 461.0375MHz ∼ 469.5625MHz Tx Frequency range Tx VCO Frequency range Same as item 1 Same as item1 RX Frequency range 4439.6375MHz ∼ 448.1625MHz ( Lower Heterodyne ) RX VCO Frequency range Channel Number...
  • Page 7: Detailed Specification

    BR777 PRODUCTION SPECIFICATION 2. DETAILED SPECIFICATION A. RECEIVER SECTIONS * Normal test condition * TYP. LIMIT 1. MAXIMUM USABLE SENSITIVITY * 1KHz +/-1.5KHz DEV. -120dBm <-118dBm * REF. CHANNEL 1 & 4 2. 20dB QUIETING SENSITIVITY * 1HKz +/-1.5KHz DEV.
  • Page 8 BR777 PRODUCTION SPECIFICATION B. TRANSMITTER SECTIONS LIMIT 1. TRANSMITTER FREQUENCY TOL. * REF. CHANNEL 1 <+/-200Hz 2. TRANSMITTER RF POWER * REQUIRED CONDUCTIVE CONNECTION * REF. CHANNEL 1 Hi Power (DC3.7V) 1.2W +0.3W / -0.2W Low Power 0.4W +0.3W / -0.2W 3.
  • Page 10 BR777 TX AUDIO TEST RESULT Frequency Response of Audio Low Pass Filter (150mV input) -8.90 -15.80 -21.10 -25.30 -28.90 -32.00 -34.50 -45.40 -52.1 -9.00 -15.90 -21.20 -25.30 -28.90 -31.90 -34.50 -45.20 -50.2 Page 1...

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