User Manual

1-1
Part No. 001-3422-003
SECTION 1
GENERAL INFORMATION
1.1 SCOPE OF MANUAL
This service manual contains alignment and service information for the Johnson Data Telemetry (JDT) DM-
3422 VHF Synthesized Telemetry Unit.
This manual concentrates on the RF section of the Data Link (DL) which may be paired with an internal
Loader board or 9600 baud Modem board.
Service manuals addressing items specific to the Loader board (Part No. 001-3240-003) and the Modem
board (Part No. 001-3295-002) should be referenced for the users specific configuration.
1.2 EQUIPMENT DESCRIPTION
1.2.1 GENERAL
The JDT DM-3422 is a synthesized data transceiver (transmitter and receiver) which operates in the 132-174
MHz VHF frequency range. Transmitter power output is 1-5 watts, 5W at 13.3V nominal. Operation is simplex or
half-duplex.
Versions of the DM-3422 covered in this manual are indicated in Section 1.5. The DM-3422 has a frequency
stability of ± 2.5 PPM (see Section 3) and is available with or without the Loader/Modem boards.
The number of channels that can be selected with the DM-3422 model is determined by the customer
supplied synthesizer loading circuitry. DL-3422 model can be supplied with the DL-3240 Loader board.
In addition to this VHF radio, JDT has a full line of radios and radio modems to meet wireless data
communication needs. Both OEM RF decks and complete FCC type approved radios and radio modems are
available from 132-174 MHz at VHF, 380-512 MHz at UHF, and 928-960 MHz at 900 MHz in both 5W and 2W
units (VHF and UHF). High Specification units are available to meet international requirements and bandwidths
to meet U.S.A. refarming requirements. To learn more about the other JDT products, call 1-800-992-7774 or
1-612-890-8155 to speak to a sales representative.