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2.4ghz wifi not seen on Pi 3B+
#1
I've been seeing a problem with my Pi 3b+,  in that the 2.4ghz wifi isnt showing up in the scan.  I see the 5ghz fine.  This is the only Pi I have , that has the dual band radio.

Other, 2.4 only ones see that and connect fine.  I had been seeing both , beforehand Im pretty sure,  but several updates ago it stopped.  Probably before 5.0

Any idea on what might prevent  the player from seeing thr 2 4g wifi?
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#2
@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
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#3
(06-11-2019, 10:02 AM)TheOldPresbyope Wrote: @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.
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#4
Forgot about moOde going into AP mode if it doesn't find a connection. That would be confusing, for sure. I'm not sure what to suggest next but if I think of something I'll give a shout.

Regards,
Kent
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#5
(06-13-2019, 01:52 PM)TheOldPresbyope Wrote: Forgot about moOde going into AP mode if it doesn't find a connection. That would be confusing, for sure. I'm not sure what to suggest next but if I think of something I'll give a shout.

Regards,
Kent

Well,  I did some more research,  and found that despite having some issues with my router setup as it was, (experimenting with bleeding edge versions of OpenWrt)  reverting to the stable version improved but did not solve my problems.

I now can (usually) see the 2.4g wifi in the Moode scan,  I still have lousy to no luck in getting it to work after selecting it, though.  Thought I had it for a short while,  then no page refreshing,  then it's back to dropping out and returning to AP mode with "Moode" showing up in my local wifi listing for the PC.  And I'm back to settng it for my 5ghz wifi,  where it reliably connects and stably works.

I guess researching how the Pi selects one radio or the other,  or can one get config'ed funny while the other is OK,  might be a path forward.  I know that THIS Pi 3b+ used to work on 2.4g,  but suddenly stopped, a version or two (or 3) back.  I don't know how it gets confused somehow, without it being a Moode issue,  but that begs the question, if so, why isn't everybody on 5.x on a dual wifi Pi having the problem?  So, it's probably something else. 

Things I'll try...   It's pretty far away from my AP. Maybe a weak signal introduces issues. I  will bring it closer.  But, the 5ghz works,  which usually has less range than the 2.4g. 

Will try to learn the basic RPi dual wifi radio settings,  to see if something ain't right.
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#6
You could try reverting to the 4.14.98 kernel.
http://moodeaudio.org/forum/showthread.p...2#pid11222

-Tim
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