The Current 435 repeater rack, top to bottom:
- Internet remote controlled AC Power switch.
- Control / link radios.
- Radio mount (unused)
- Internet stack: router, firewall, switch, VoIP interfaces.
- Samlex 1KW 120v AC power inverter for battery backup.
- Linux computer; 8-core; VoIP interfaces, audio logging, analysis, finger printing.
- Dual RF TX circulator.
- 2m repeater based on a GE Mastr (Custom).
- RLC Club Deluxe II 6-port repeater controller.
- Samlex 100A 12V power supply.
- Motorola timebase (unused).
- 2m TX Henry RF amplifier.
- 2m RX Preamp.
- 2m duplexers and band pass cavities.
- Batteries for inverter backup power.
More Detail on the Custom GE Repeater
The core repeater is a rebuilt GE with RX helical resonator front-end. The repeater is based on a GE Mastr II RX shelf converted to uMASTR II configuration with TX based on an Mastr Exec II PA frame gutted & rebuilt with a modern FET-brick and reworked crystals. We have a custom front panel, wiring harness and connectors compatible for our controller, finger printer, etc. The new TX FET-brick is cleaner and more efficient than the original class C PA; and should last for years at 100% duty cycle.
We stayed with the GE dual-hysteresis squelch and CTCSS filter. They’re amazing! CTCSS is completely removed, but recovered audio is otherwise unchanged. Thus a fairly flat audio is realized. The transmitter exciter includes its own special audio input for flat-below-4KHz TX audio. No limiter or clipper is present, or pre-emphasis; only the factory adjacent-channel splatter filter. Within the bandwidth limits of our 2-Meter channel, this is the ideal setup for high-fidelity audio.
The Mastr Exec II TX PA frame on the back is a bit crusty on the outside, but it’s now beautiful inside with the new power brick and precision variable resistor for fine-tuned RF power adjustment. The frame came from an Exec with 435 crystals. We cleaned it up a bit and added a heatsink fan before it was deployed on the hill September 2016.