User's Manual

VRS750 Global Tuner
The Tuner for Professional Radios (Global Tuner) can be used to adjust the VRS750’s
Transmitter Output Power and Receiver Squelch Settings. In order to program the
VRS750 using the Global Tuner it should be connected to the mobile and to a PC via its
COM port as indicated in Figure 12.
Figure 12 VRS connection to the PC
Once the setup is complete and the mobile is turned on the current tuning parameters can
be read from the VRS750 by selecting File->Read Radio Information and Softpots on
the Global Tuner.
Note: Radio Serial Number and Radio Model Number shown at the bottom of the screen
will not match the model number and serial number of its associating VRS.
To adjust the Transmitter Output Power select TX Align->Transmit Power->High (or
Low) (see Figure 13). High and Low are associated with the VRS Output Power setting
in the VRS Personality window of ASTRO CPS. This will bring up a window of seven
test frequencies and their current softpot values. By increasing the softpot values the Tx
Output Power will be increased up to a Max of 4 Watts (UHF) or 5 Watts (VHF). Be
sure to adjust all seven softpot settings to the desired power level using a RF power
meter. The VRS750 determines its Tx Output Power by comparing the programmed
frequency to the test frequencies and selecting the softpot value of the one that is closest.
Once the softpots have been set to the desired power level click on the program button
and close the Transmit Power window by using the X in the top right corner. At this
point the mobile radio will reset. After the reset is complete select File->Program All.
This will program all adjusted softpot values into theVRS750’s EEPROM.
VRS7 SRIB
Connect to the PCs
COM Port
ASTRO Mobile