147.105

The repeater uses repackaged GE and other components with custom features added. The receiver is a modified GE Executive series. The exciter is a modified GE MASTR II of the PLL variety. It drives a 20 watt amplifier salvaged from an old KDK 2-meter transceiver. A home built squelch based on the famous Motorola squelch chip from a Micor has been added, along with signal strength and discriminator meters and some special control circuitry and indicators. The repeater controller is a Link Communications RLC-4 in the 2 meter repeater cabinet. Port 1 of the controller is internally wired to the 2 meter receiver and transmitter, while ports 2 through 4 are wired to DB9 connectors on the repeater rear panel for connection to external repeaters. When the system is on "high power" an external 110 watt amplifier repackaged from a GE MASTR II mobile is used. Thermostat controlled forced air cooling keeps the amplifier temperature within safe limits. A home built 13.8 volt 30 amp continuous duty power supply powers the repeater and charges a backup battery. The 110 watt amplifier has its own 30 amp power supply salvaged from an old RCA VHF base station. The amplifier does not have battery backup as it would discharge the battery very quickly.

A Decibel Products DB4062B six cavity duplexer provides receive/transmit isolation, allowing the use of a single antenna for both transmit and receive. Two additional Decibel Products 11 inch pass cavities (one in the receive path and one in the transmit path) were added to prevent interference from or to a nearby APRS digipeater. There is a home built GaAsFET preamp between the receive side pass cavity and the receiver.

The feedline is approximately 120 feet of LDF5-50A (7/8 inch) heliax. The antenna is a Sinclair SRL235-2 dipole array with its center 95 feet above ground.

444.950

The UHF repeater is more of a "quick and ugly" approach. The repeater is a Motorola Micor mobile with duplex modifications. It runs at 25 watts. I did mount it on a rack panel with easily accessible volume and squelch controls, a few status indicators, and a local speaker. It is connected to port 2 of the RLC-4 controller located in the 2 meter repeater cabinet. This repeater has its own home built power supply and does not have battery backup available.

The duplexer is a Motorola T1504A which was built from individual cavities scrounged from various sources. Some were flood damaged. All were disassembled and completely cleaned. There is a home built GaAsFET preamp on the receive port of the duplexer.

The antenna is a home built 10 element coaxial collinear approximately 50 feet above ground and fed with 75 feet of LDF5-50A (7/8 inch) heliax.

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