Setting channel on 900 MHz node shuts down RF #2324
Description
Describe the bug
On 900 MHz nodes (both Rocket M9 and NanoStation Loco M9) running 3.25.5.1 and later, setting the channel / frequency results in:
- no RF output (confirmed with spectrum analyzer)
- iwinfo reports "Channel: unknown"
- Radio section on information page displays nonsense
A 900 MHz node in which the frequency was only set with the old UI and then upgraded to 3.25.5.1 or later will operate correctly and show the corresponding 2.4 GHz channel number, although the frequency display is empty. After subsequently changing the frequency through the new UI, however, the RF shuts down and the channel number becomes nonsense (e.g. -299), but the frequency display shows the expected value.
If the node is then downgraded to 3.25.2.0, the frequency can be reset and the node will operate correctly. Nevertheless, if subsequently re-upgraded to 3.25.5.1, it will revert to the settings previously established under that version and will not operate correctly.
- Does this issue still occur on the latest version? Yes, as of 20250707-307d9e2f
Expected behavior
After changing the frequency setting, the node should display the new channel and frequency and transmit on that frequency.
Support data
supportdata-K3PGM-M900-Field-2025-7-12-18-9.tar.gz
supportdata-K3PGM-M900b-2025-7-12-18-8.tar.gz
[The support data for W3DRA-EB-9-SE is not currently accessible; sorry.]
Screenshots
Rocket M9 running 3.25.2.0:
wlan0 ESSID: "AREDN-5-v3"
Access Point: 68:72:51:68:8A:59
Mode: Ad-Hoc Channel: 4 (2.427 GHz) HT Mode: HT20
Center Channel 1: 4 2: -1
Tx-Power: 28 dBm Link Quality: unknown/70
Signal: unknown Noise: -95 dBm
Bit Rate: unknown
Encryption: none
Type: nl80211 HW Mode(s): 802.11b/g/n
Hardware: 168C:002A 0777:E1B9 [Ubiquiti Rocket M9]
TX power offset: 6 dB
Frequency offset: none
Supports VAPs: yes PHY name: phy0
NS loco M9 running 3.25.2.0:
wlan0 ESSID: "AREDN-5-v3"
Access Point: 68:72:51:6A:F9:C3
Mode: Ad-Hoc Channel: 5 (2.432 GHz) HT Mode: HT20
Center Channel 1: 5 2: -1
Tx-Power: 28 dBm Link Quality: 70/70
Signal: -30 dBm Noise: -95 dBm
Bit Rate: 130.0 MBit/s
Encryption: none
Type: nl80211 HW Mode(s): 802.11b/g/n
Hardware: 168C:002A 0777:E009 [Ubiquiti NanoStation Loco M9]
TX power offset: 6 dB
Frequency offset: none
Supports VAPs: yes PHY name: phy0
Rocket M9 running 20250707-307d9e2f but frequency was previously set with old UI:
wlan0 ESSID: "AREDN-5-v3"
Access Point: 68:72:51:68:89:65
Mode: Ad-Hoc Channel: 5 (2.432 GHz) HT Mode: HT20
Center Channel 1: 5 2: -1
Tx-Power: 28 dBm Link Quality: 70/70
Signal: -26 dBm Noise: -95 dBm
Bit Rate: 130.0 MBit/s
Encryption: none
Type: nl80211 HW Mode(s): 802.11b/g/n
Hardware: 168C:002A 0777:E1B9 [Ubiquiti Rocket M9]
TX power offset: 6 dB
Frequency offset: none
Supports VAPs: yes PHY name: phy0
Aforementioned NS loco M9 after upgrading to 3.25.5.1:
Note that the Frequencies display has mysteriously shifted to 915 - 919 MHz, the channel number is -298, and iwinfo shows Channel: unknown:
wlan0 ESSID: unknown
Access Point: 68:72:51:6A:F9:C3
Mode: Ad-Hoc Channel: unknown (unknown) HT Mode: NOHT
Center Channel 1: -1 2: -1
Tx-Power: 28 dBm Link Quality: unknown/70
Signal: unknown Noise: unknown
Bit Rate: unknown
Encryption: none
Type: nl80211 HW Mode(s): 802.11b/g/n
Hardware: 168C:002A 0777:E009 [Ubiquiti NanoStation Loco M9]
TX power offset: 6 dB
Frequency offset: none
Supports VAPs: yes PHY name: phy0
Note: the frequency of this node was set to 917 MHz previously while running 20250707-307d9e2f, which I suspect is why it reverted to that frequency after upgrading. Subsequently setting the frequency to 912 MHz changes the display to:
...but iwinfo still shows "Channel: unknown" and there is no RF output.
Additional context
Add any other context about the problem here.