Comtech EF Data TRP500 - Manual (Page 67)

B–1
Appendix B. REMOTE CONTROL
B.1 Introduction
This appendix describes the operating features of the Troposcatter Outdoor Amplifier (TRP500). A
few key parameters and procedures are summarized, followed by detailed instructions of remote
control communication commands. The remote commands for the TRP500 closely match Comtech
EF Data’s other SSPA (Solid State Power Amplifier) product lines.
B.1.1 RF Input Level
The required RF input level to reach the full rated output power of the SSPA is determined by the
individual amplifier maximum gain and power rating. For example, if the test data of a SSPA rated
for 250W (54 dBm) indicated a gain of 40 dB, then a signal of 54 dBm – 40 dB = 14 dBm would
approximately give the rated output power. Increasing input power beyond this level would result in
an output signal with increasingly higher levels of distortion. The maximum input level should
never exceed 30 dBm, or permanent damage to the unit may occur.
B.1.2 Gain Control
The TRP500 is temperature compensated to maintain its gain over the unit’s specified temperature
range.
B.1.3 Mute Control
The TRP500 may be muted via software or discrete control. Exercising the MUT=1 command will
“software” mute the unit. The TRP500 also may be “hardware” muted by pulling Pin ‘S’ on the
J6 (COM1) Discrete control connector to ground (See Chapter 2. SYSTEM CONNECTIONS,
INSTALLATION
AND OPERATION).
The Mute command provides over 30 dB of RF on/off isolation. However, the Mute command
only turns off the first stage of the amplifier, the high power stages remain on. By allowing the
higher power transistors to stay on, the TRP500 remains in a more thermally stable state should
the mute condition be removed.
If the user desires to completely turn off the bias to the entire amplifier (perhaps to conserve
energy in a redundant system), both the
MUT=1 and AMP=0 commands should be executed. For
normal transmit operation, MUT=0 and AMP=1 are required.