User's Manual

TM-200 Issue 1.02 November 2005 Page 24 of 64
Setup of IF Pre-Correction on Signal Conditioning PCB
1. Install the modulator but do not apply power yet.
2. Ensure that the two IF pre-correction potentiometers on the front panel of the
modulator are turned fully counter clockwise.
3. With the transmitter and modulator fully installed, apply power and bring the
transmitter up to rated power.
4. Apply a red field test signal to the input of the modulator with the aural carrier
turned on.
5. Take a sample of the RF output and view it on a spectrum analyzer.
6. Looking at the +/- 920kHz intermodulation products, adjust the two IF pre-
correction potentiometers to obtain the lowest level on the intermodulation
products.
Varying these two pots can increase and dec
rease the
output power, so this should be carefully monitored.