My latest ham radio project is assembling a portable repeater for VHF and UHF operation. The basic idea is to package two VHF/UHF transceivers and a repeater controller into a rack mount box that can be easily transported and powered from a 12 VDC source.
I chose the Yaesu FT-7800R for the transceivers since it covers the 2M and 70 cm bands and has a data/packet port for easy access to the required control signals. Specifically, the data port has transmit audio in, receive audio out, squelch signal and PTT (Push To Talk). The repeater controller used is the NHRC-6, which is designed for use as a bridging controller between two transceivers. Most repeater controllers are set up for a conventional repeater configuration, always receiving on one frequency and always transmitting on another. I plan to use the repeater in this mode (on the 70 cm band, with a small UHF duplexer) but also wanted to run the transceivers in a crossband repeat mode. The NHRC-6 handles this quite well, able to route audio in both directions between two transceivers and with identification support for both rigs.
I’ve got the system assembled and I am playing around with the configuration. More to follow, probably in a CQ VHF article.
73 Bob K0NR