MMDVM DMR Repeater

After a year of assembling, programming, troubleshooting and tweaking, we recently put up a MMDVM (Multi-mode Digital Voice Modem) repeater for the south end of Davis County, UT. Last year I entered the world of digital voice with a purchase of an MD-380 digital DMR handheld radio. Since our area lacked good repeater coverage, I decided to try to build a repeater to help fill in some of the coverage gaps.

One of the hardest parts of putting a repeater on the air was simply getting a frequency coordination for the 70 cm band. The key pieces of the repeater are the actual MMDVM board that sits on an Arduino Due board. The Due is connected to a Raspberry Pi which runs G4KLX’s MMDVMHost software that interfaces with the MMDVM software on the DUE¬† and connects the repeater to the Brandmeister DMR network. The radios are two Motorola CDM-1550LS+ radios connected via duplexer to a Diamond X-50A antenna.

Below are some pictures of the repeater:

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