User's Manual

Programming Mode
The programming mode allows the user to retrieve or program TX/RX frequencies, HI/LO power
Setting and channel spacing, when pin 9 of J501 is set to ground. Programming mode will Inhibit,
Serial communications can then be made in order to read/program the on- board EEPROM
( IC502 )which contains radio- specific data.
EEPROM
Relevant channel information, such as RX / TX frequencies, is stored in the EEPROM (IC502)
which is a 93C46. This information may be programmed and erased via the D- type socket. The
EEPROM has 1024 (8x128) capacity and is written serially.
Power supply circuit
The data radio is supplied with a nominal + 13.8V dc power supply input from external equipment
which is filtered using C532 ,L501 and C533.This supply is converted into three separate voltage
levels on the board using the switching transistor Q506 and associated components .
The +13.8Vdc supply and Q506 switching waveform are summed using D503 to supply a boosted
voltage supply, which is regulated at +16V using Zener diode D506. This supply is used as the
supply for the tuning voltage for the VCOs.
The +6V line is regulated by Zener diode D505 and filtered using L503 and C538.This +6V line is
fed to the RF circuit and is regulated to +5V using two regulators on the board.
4. PERFORMANCE TEST AND ALIGNMENT
The alignment and performance test procedures assume the use of the following equipment.
Discrete test equipment
Volt Meter Spectrum Analyzer and notch filter (option)
RF Power Meter. Coupler (20dB isolation)
DC Power Supply, 0-15V 2A min
Oscilloscope, 20 MHz dual beam
RF Frequency Counter,
100 kHz - 600 MHz
AF Signal Generator 0 – 20 kHz
RF Signal Generator
SINAD Meter
Modulation Meter
Audio Power Meter
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