MURS Channel Assignments & Programming
The MU-5 is really a Radioddity GM-30 in MURS clothing. The only meaningful difference is in the firmware: a frequency whitelist and a fixed 2-watt power ceiling. This is a common pattern in the cheap Chinese radio market.
Fixed MURS Channels (1–20)
The first 20 channels are permanently assigned to the five MURS frequencies, repeating in a cycle of four:
| Channels | Frequency (MHz) | MURS Ch | Bandwidth |
|---|---|---|---|
| 1, 6, 11, 16 | 151.8200 | 1 | Narrowband (NFM) |
| 2, 7, 12, 17 | 151.8800 | 2 | Narrowband (NFM) |
| 3, 8, 13, 18 | 151.9400 | 3 | Narrowband (NFM) |
| 4, 9, 14, 19 | 154.5700 | 4 | FM |
| 5, 10, 15, 20 | 154.6000 | 5 | FM |
These channels cannot be reprogrammed, not in the radio's CPS software, not in CHIRP, and not by any other means short of writing custom firmware. The frequencies aren't even stored in the radio's EEPROM the way normal channels are. The firmware hardcodes the MURS frequency based on the channel number; the EEPROM locations for channels 1–20 contain 0xFFFFFFFF (blank) for both RX and TX frequency, and the radio just ignores them.
The things you can change on channels 1–20 are CTCSS/DCS tones, the channel name, scan skip, and per-channel extras like Busy Lock. So you can still set up privacy tones for your group—you just can't move the channels around.
RX-Only Channels (21–250)
Channels 21 through 250 are user-programmable, but they are receive-only. You can tune them to any frequency the radio's UHF + VHF front end can pick up, which makes them useful as a scanner of sorts—monitor NOAA weather, local business band, whatever you like. But the radio will not transmit on these channels regardless of how you program them.
Programming with CHIRP
CHIRP supports the MU-5. When you open the MU-5 in CHIRP, you'll see that channels 1–20 have their frequency, duplex, offset, and power columns grayed out. This isn't a CHIRP limitation—it's reflecting the actual firmware constraints. CHIRP marks these fields as immutable because writing different values to the EEPROM would have no effect; the radio would still transmit on the hardcoded MURS frequency regardless of what the EEPROM says.
What CHIRP will let you do is edit tones, names, and scan settings on those first 20 channels, and fully program frequencies on channels 21–250 (for receive-only use).