2.4ghz wifi not seen on Pi 3B+

[JonPike]

@JonPike

Are you sure you have the Country Code set correctly? Funny things can happen with the WiFi interface if it isn't.

In my townhouse an RPi3B+ WiFi scan picks up 14 different access points from around the neighborhood, some lowband and some highband.

From the command line, you can execute the command sudo iwlist wlan0 scan and see lots of info about the access points detected (ennumerated as Cell 01, Cell 02, ..., Cell 14 in my case). Here's a snippet from my scan (where i've elided some hex data)

Code:

pi@moode53K:/var/www/inc $ sudo iwlist wlan0 scan
wlan0     Scan completed :
         Cell 01 - Address: 48:5D:36:AE:11:40
                   Channel:6
                   Frequency:2.437 GHz (Channel 6)
                   Quality=45/70  Signal level=-65 dBm  
                   Encryption key:on
                   ESSID:"Phyllis"
                   Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
                             24 Mb/s; 36 Mb/s; 54 Mb/s
                   Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 48 Mb/s
                   Mode:Master
                   Extra:tsf=0000000000000000
                   Extra: Last beacon: 50ms ago
                   IE: Unknown: xxxxxxxxxxxxxxxxxx
                   <seven more lines of IE: Unknowns>
                   IE: IEEE 802.11i/WPA2 Version 1
                       Group Cipher : CCMP
                       Pairwise Ciphers (1) : CCMP
                       Authentication Suites (1) : PSK
                   IE: Unknown: xxxxxxxxxxxxxxxxxxxxxxxxx
                   <seven more lines of IE: Unknowns>
         Cell 02 - Address: 48:5D:36:E9:0B:2A
                   Channel:1
                   ...

It could be interesting to compare the 2.4GHz cells detected by your 3B+ and your other RPis.

Regards,
Kent

Well, Kent,  I checked the country code,  no prob there,  and eventually discovered I was having issues w the 5ghz radio.  NOT the 2.4ghz that I was having issues seeing.  Found when you dont get a connection to your configured radio, you eventually time out and go back to AP mode.  All that just made it difficult to get back into the player...

Eventually i got things working in the router,  got the player back up on 5ghz,  (but still not seeing the 2.4!) and was able to run that command to see what the radios heard.  Can post the results later,  but Im seeing 5-6 stations, both 2.4 and 5ghz radios,  my 5ghz radio,  but not my 2.4. Very strange.  On my 2.4 only Pi 3,  I see 8 stations, and of course my 2.4ghz that its connected to.  Got em both up to 5.31 now. Will look at it more tomorrow.  Open to other diagnostic ideas.