Microwave Data Systems MDS 4310, Installation, Operation & Field Maintenance

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4-2 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A
TEST EQUIPMENT REQUIRED
Continued
Frequency measuring equipment usually requires a “warm-up” period to achieve
maximum accuracy; a warm-up period of 30 minutes is not uncommon. Please read
the unit’s instruction manual before proceeding with frequency measurements.
NOTE
FCC regulations require a frequency accuracy of .00015% (1.5
ppm). MDS transceivers meet this requirement by using
temperature compensated crystal oscillators. A frequency counter
used to set the transceiver on-frequency must have an accuracy
that is five to ten times better than what it is reading, which is an
accuracy of .00003% to .000015% (0.3 to 0.15 ppm).
If a frequency counter with a frequency accuracy of better than 0.3
ppm is not available, do not make any adjustments to the
transceiver frequencies.
DC Voltmeter—A digital voltmeter such as a Fluke 75 is suitable.
Oscilloscope—If the service monitor does not contain a low frequency oscilloscope, then
a basic one is required. The oscilloscope should have a frequency response of 100
kHz or higher, AC/DC coupling and have a horizontal sweep resolution of 2 ms per
division.
MDS Hand-Held Terminal (HHT)—Kit P/N 02-1501A01. The HHT is most
convenient way to set the operating parameters controlled by the transceiver’s micro-
controller, and to use the built-in test and diagnostic features of the radio.
NOTE
To perform the tests in this chapter, operators must be familiar
with connecting the HHT, opening and closing the Diagnostics
Channel and issuing the required commands. Chapter 3—
Programming and Diagnostics contains complete instructions
for using the HHT.
If desired, a personal computer running a standard terminal emulation program such
as PCPLUS™ or PROCOMM™ can be substituted for the HHT. In this case, the
program should be set to 1200 bps, eight data bits, no parity, and one stop bit. The
keyboard must be set with the
caps lock
key pressed; the radio responds only to
commands and numbers entered in uppercase characters. The commands for a PC are
identical to those used with the HHT. (See Chapter 3—Programming and
Diagnostics, for more information.)
Room Thermometer—This thermometer should be accurate to 1
°
C. It is used to
calibrate the temperature sensor on the Remote Maintenance Module.
Power Supply—The output needs to provide 12–14 Vdc at 3 amperes or more.
Small, flat-bladed adjustment tool—It is used to adjust potentiometers on the
transceiver. It should be made of plastic or metal.
Data Terminal Emulator—This device is required for radios with a built-in modem
installed. It is used to key the transceiver and simulate incoming data on the DB-25
INTERFACE
connector. A simple terminal emulator can be wired for this purpose as