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Quantar mixed mode with multi PL/DPL

Posted: Sat Sep 26, 2015 2:06 pm
We have a ham UHF repeater that we need to maintain mixed mode and multi DPL/PL decode. The station control module supplies the decoded PL and audio into a Zetron 38 and the Zetron supplies DPL/PL tone into control module. The repeater audio and PTT and Cor come from MRTI connector. The repeater is set to carrier with high pass filter in off position. The Mod comp setting is important for DPL to work and needs to be aligned. The out of U305 pin 14 will have audio with PL/DPL to feed disc input on Zetron panel and tone out I'd Zetron panel needs to be connected to pin 3 of U318A via a 12 K resistor. I put a dual shielded cable between the RJ connectors to supply signals to The Zetron. The MRTI is used for PTT and Transmit audio and Cor to Zetron. The control feed PL and DPL to panel. I started with tone panel in factory default and found that the input PL/DPL needed to set for invert. The output was correct. The mods to station logic are on top and bottom of board with surface mount parts and require a chip resistor and wires to be added.

The Zetron sets hang time for analog and quantar is set for 0 hang time in software. I have used this with older control modules as long as MRTI connector worked for external audio. P-25 is working with no carrier hang time. I tried to get wide band audio from outboard connectors and was not successful. This mod requires a person who can work with surface mount parts in anti static envirement. I used hot glue to hold wires on control module to route on board.
Our repeater club can use multi PL and P-25 now without replacing our existing repeater.

D/A U303 via buffer U305D feeds PL/DPL to panel. U318A feed PL/DPL to exciter. Repeat audio and PTT and Cor is MRTI connector.