These instructions describe alignment of the RF assembly of the UHF MASTR II receiver. The IF and Mixer alignment is not included; it rarely needs to be performed. You will need to consult the GE MASTR II Maintenance Manual for these instructions.

Some older receivers will not have the three trimmer capacitors (C406, C411, and C416) on the Oscillator/Multiplier board, they will have three inductors (L401, L402, and L403, from front to rear) with tunable slugs instead. Follow the directions as shown, but adjust L401 instead of C406, L402 instead of C411, and L403 instead of C411.

UHF MASTR II Receiver Alignment Controls Locations

Mixer and IF alignment is almost never required. Do not attempt to align the mixer or IF stages of the receiver without at least a signal-to-noise analyzer.

The frequency of the receiver ICOM can be adjusted by turning the trimmer capacitor on the top of the ICOM. The frequency can be measured directly with a frequency counter connected to the junction of C416 and L403 on the Oscillator/Multiplier board (frequency here should be (receive frequency - 11.2) / 3) or the ICOM's frequency can be adjusted by injecting a signal into the receiver from a known reliable source (signal generator or service monitor) and tuning the ICOM for best receive sensitivity.

All transmitter alignment measurements are performed with the transmitter keyed. Do not leave the transmitter keyed for an extended period until the alignment is complete. Make sure that a wattmeter and dummy load are connected to the transmitter output.

UHF MASTR II Transmitter Alignment Controls Locations

Use a frequency counter or service monitor to adjust the transmitter ICOM. The trimmer capacitor on the top of the ICOM adjusts the ICOM's frequency, and therefore the transmitter's output frequency.

Transmitter maximum deviation is set with R104. Note that this control adjusts the deviation level after the limiter. This control should be adjusted to ensure that maximum deviation does not exceed 5.0 KHz. A service monitor or deviation meter is required to make this adjustment. If you do not have the required test equipment, then don't adjust the deviation control, it's probably fine right where it is.

When setting power level, do not exceed rated output power. If the radio will be used as a repeater, or in any other similar high-duty-cycle application, then the maximum output power should be derated to 1/2 to 2/3 of the specified rated output power.