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How can I override the wlan driver's region limitations to permit the (legal) 900MHz unlicensed operation of my 802.11ah evaluation kit?

The [Silex evaluation kit for 802.11ah][1] doesn't seem to work at sub-GHz. A spectrum analyzer shows no power in the sub-GHz. It is operating, apparently, at 5.825GHz. Their support email has failed to respond after 11 days and this appears to be a problem with the SSD that comes with the kit as evidenced by the following output.

pi@raspberrypi:~ $ iwconfig wlan0
wlan0     IEEE 802.11  ESSID:"Wi-Fi"  
          Mode:Managed  Frequency:5.825 GHz  Access Point: 84:25:3F:87:FA:E8  
          Bit Rate=6 Mb/s   Tx-Power=30 dBm  
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=70/70  Signal level=-32 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:100   Missed beacon:0

pi@raspberrypi:~ $ cat ~/sx-newah/conf/US/sta_halow_sae.conf
ctrl_interface=/var/run/wpa_supplicant


country=US
network={
    ssid="Wi-Fi"
    proto=RSN
    key_mgmt=SAE
    ieee80211w=2
    pairwise=CCMP
    group=CCMP
    sae_password="12345678"
    freq_list=2422 2432 2442 2452 2462 5180 5185 5190 5195 5200 5205 5210 5215 5220 5225 5230 5235 5240 5745 5750 5755 5760 5500 5520 2437 2457 5765 5770 5775 5780 5785 5790 5795 5800 5805 5810 5815 5820 5825
    scan_freq=2422 2432 2442 2452 2462 5180 5185 5190 5195 5200 5205 5210 5215 5220 5225 5230 5235 5240 5745 5750 5755 5760 5500 5520 2437 2457 5765 5770 5775 5780 5785 5790 5795 5800 5805 5810 5815 5820 5825
}
p2p_disabled=1
ignore_old_scan_res=1


pi@raspberrypi:~ $ iw reg get
global
country US: DFS-FCC
(2402 - 2472 @ 40), (N/A, 30), (N/A)
(5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
(5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
(5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
(5735 - 5835 @ 80), (N/A, 30), (N/A)
(57240 - 63720 @ 2160), (N/A, 40), (N/A)

PS: I've tried modifying the conf files.
[1]: https://www.silextechnology.com/connectivity-solutions/embedded-wireless/sx-newah-evaluation

James Bowery
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1 Answers1

0

Partially my mistake. It is, indeed, operating in the 900MHz spectrum.

What threw me off was the agreement between all of the command outputs provided in the question, that there was no support for 900MHz, in combination with a mistake of my own:

I modified the "freq_list" (and scan_freq) to include the 900MHz frequencies. This caused the driver to fail to broadcast at all. I didn't realize this, so upon taking delivery of the spectrum analyzer nothing was showing up in 900MHz thereby "confirming" my belief the unit was operating at 5GHz (the spectrum analyzer I bought only went up to the 2.4GHz range). Only after realizing that the radio might not be broadcasting at all did I revert the configuration to the original. At that point the spectrum analyzer showed 928MHz power.

James Bowery
  • 121
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