Table of Contents
Features......................................................................................................................................................... 1
Technical Specifications (Typical Unit):.............................................................................................. 2
Receiver: ......................................................................................................................................... 2
Transmitter: .................................................................................................................................. 2
Simplified Technical Description: ......................................................................................................... 3
MFJ-8621 Technical Description: ...................................................................................................... 3
General: ........................................................................................................................................... 3
Receiver: ......................................................................................................................................... 3
Transmitter: .................................................................................................................................. 3
T/R Switching: ............................................................................................................................. 3
TNC Data Carrier Detect Compatibility ............................................................................................ 4
Connecting To Your MFJ-8621:.......................................................................................................... 4
Power Supply: ............................................................................................................................... 4
Antenna:.......................................................................................................................................... 5
TNC Connection:.......................................................................................................................... 5
RFI:..................................................................................................................................................... 5
Selecting Baud Rate: ................................................................................................................................ 6
Receiver Filter:.............................................................................................................................. 6
Transmitting:................................................................................................................................. 6
Transmitter Deviation: ............................................................................................................................. 6
Setting Deviation: ........................................................................................................................ 6
Two-Way Deviation Monitoring: ............................................................................................ 7
Confirming Deviation: ................................................................................................................ 7
Ordering Crystals: ...................................................................................................................................... 8
Receiver Crystal:.......................................................................................................................... 8
Transmitter Crystal:................................................................................................................... 8
Installing Crystals: ...................................................................................................................................... 9
Crystal Oscillator Calibration:................................................................................................................ 10
Transmit Oscillator:.................................................................................................................... 10
Receiver Oscillator:..................................................................................................................... 10
More About 9600-Baud FSK Packet Signals: ............................................................................... 11
Sending And Receiving 9600-Baud Data: ....................................................................................... 11
In Case Of Difficulty:................................................................................................................................... 12
1. Unable To Copy Off-Air Signals: ........................................................................................ 12
2. Unable To Connect:............................................................................................................... 12
3. Transmitter Erratic Or Inoperative: ............................................................................... 12
Important Operator Notes:.................................................................................................................... 12
Appendix......................................................................................................................................................... 13
Technical Assistance................................................................................................................. 13
Replacing The Fuse Link........................................................................................................... 13
