DANIELS
ELECTRONICS LTD.
TM
iv IM10-VR3H040-AB
VHF Enhanced Extra Wideband Receiver Instruction Manual
3.2.4 RF
Amplifier.................................................................................................. 3-9
3.2.5 Image Rejection Filter ................................................................................... 3-9
3.2.6 Local Oscillator Filter.................................................................................... 3-9
3.2.7 Double Balanced Mixer................................................................................. 3-9
3.3 Enhanced Synthesizer...................................................................................... 3-10
3.3.1 Internal Power and Control (Digital Board) ................................................ 3-10
3.3.2 Common Analog Board Circuitry................................................................ 3-10
3.3.3 29 - 71.4 MHz Analog Board Circuitry....................................................... 3-12
3.3.4 Synthesizer Digital Circuitry (Digital Board) ............................................. 3-13
3.4 Frequency Control ........................................................................................... 3-13
3.4.1 BCD Switch Frequency Control.................................................................. 3-13
3.4.2 Synthesizer Base and Frequency Increment Table...................................... 3-14
3.4.3 5.0/6.25 kHz Channelization. ...................................................................... 3-14
4 RECEIVER
ALIGNMENT ....................................................................................... 4-1
4.1 General............................................................................................................... 4-1
4.2 Repair Note........................................................................................................ 4-1
4.3 Printed Circuit Board Numbering Convention .................................................. 4-2
4.4 Recommended Test Equipment ......................................................................... 4-2
4.5 Synthesizer OS-3, OS-3H)................................................................................. 4-3
4.5.1 VHF OS(R/T)-3H 29 - 71.4 MHz VCO Alignment ...................................... 4-3
4.6 Front End Tuning............................................................................................... 4-5
4.7 Main Board Tuning............................................................................................ 4-6
4.7.1 IF Amplifier Bias Current Adjustment .......................................................... 4-6
4.7.2 21.4MHz ........................................................................................................ 4-6
4.7.3 Audio
Levels.................................................................................................. 4-6
4.7.4 Distortion and Sensitivity .............................................................................. 4-7
4.7.5 Second IF / Demodulation ............................................................................. 4-7
4.7.6 Squelch
Window............................................................................................ 4-8
5 RECEIVER
CONFIGURATION AND TEST POINTS........................................... 5-1
5.1 21.4 MHz IF / Audio Main Board Factory Settings .......................................... 5-1
5.1.1 The 21.4 MHz IF/Audio Main Board Configuration: ................................... 5-1
5.1.2 The 21.4 MHz IF/Audio Main Board Configuration Jumper Settings.......... 5-1
5.1.3 Test
Points ..................................................................................................... 5-2
5.1.4 Power
Supplies .............................................................................................. 5-3
5.1.5 21.4 MHz IF / Audio Board Interconnect Pin Definitions ............................ 5-4
5.2 Enhanced Front End Test Points....................................................................... 5-4
5.3 OS(R/T)-3(A/H) Synthesizer Factory Configuration ........................................ 5-5
5.3.1 Jumper
Configuration .................................................................................... 5-5
5.3.2 Synthesizer Test Points.................................................................................. 5-6
