[arm-allstar] WIFI Issue

[David McGough]

Hi Tom,

I'm interested to hear about your sporadic WiFi issues, I'm not sure what 
the cause could be.

I run *ALL* my RPi3 nodes, whether test/development or live/production, 
via WiFi. I don't have any RPi3 wired by Ethernet cable, anywhere. And, I 
never recall any network hiccups that weren't from my own causing...I do 
run static IP addresses everywhere.

...For some examples, on my development AP (a ubnt bullet M2), I've got an
uptime of 173 days. And, I just checked a in-cabinet LocoM2 AP at a
production site and have an uptime of 301 days!  My production RPi3 boards
only currently have an uptime of 11 days, since that was when I pushed out
my most recent beta-test code to them and rebooted. I've got a couple
developement RPi3's, which include NFS mounted dev filesystems that have
been up 60+ days.

I've found the key to stability is good power to the RPi3's and high 
quality (which doesn't mean expensive!) Access Points.

For in-cabinet or close range WiFi use, make sure to turn the RPi3 and AP
TX power WAY down...I usually set to about 0dBm (iwconfig wlan0 txpower 0
...or maybe 10)....Even with the power turned down my signal strength is
in the -40's.


73, David KB4FXC




On Wed, 16 Aug 2017, "Tom Hayward via arm-allstar" wrote:

> I've often had RPis stop responding over wifi. I wrote a script that I
> run on the Pi to resolve the problem (rather primitively):
> 
> /home/pi/check_network_and_reboot:
> #!/bin/bash
> ROUTER_IP=192.168.1.1
> ( ! /bin/ping -c1 $ROUTER_IP >/dev/null 2>&1 ) && sudo /sbin/shutdown
> -r now >/dev/null 2>&1
> 
> 
> Then I have a crontab like this:
> */10 * * * * /home/pi/check_network_and_reboot
> 
> The script reboots the Pi when the networking stops working. In my
> experience a reboot is all that has been necessary to get the wifi
> working again.
> 
> Tom KD7LXL
> 
> On Wed, Aug 16, 2017 at 1:47 PM, "Dave P via arm-allstar"
> <arm-allstar at hamvoip.org> wrote:
> > Greetings Doug,
> >
> > Jim NH6HI and I are troubleshooting an issue with another ham's RPI3
> > system.  WA8WNK Nodes 45756/57.
> >
> > He shut down his system (connected with WiFi) before he left on Vacation.
> > With the storms in San Antonio, Texas it was a wise move.  Upon returning
> > home and firing up his equipment, he sees all the devices are recognized on
> > his wireless router to include the RPI3 WIFI connection.
> >
> > He notices his node is not being recognized on the allstarlink page.
> > Although, his CISCO Wifi router shows the RPI3 is on the DHCP list table.
> > We are unable to putty to the WIFI address of the RPI3.  I had owner Lee
> > connect the RPI3 via ethernet and I was able to SSH in with no problem.  I
> > did notice when I tried to perform an update option 1 that I go an error
> > message that the update failed.
> >
> > At this point, I am having Lee get a new MicroSD card and lets rebuild the
> > nodes again.  Jim mentioned it could be a power spike may have corrupted
> > the MicroSD card or some anomaly.
> >
> > (Additionally on the same subject of WiFi problems, we have a node 45655 on
> > Maui that went through a power outage while Jim NH6HI was on the phone with
> > the owner. When the power came back, the node wouldn't reconnect via Wifi.
> > He ran the wifi setup again and upon rebooting,  no wifi connection even
> > though it was able to complete the setup successfully. The setup was tried
> > several times to no avail.  For the interm it is connected with an ethernet
> > cable. We will be rebuilding the node on a new microSd card in the near
> > future to make sure this isn't a hardware problem.  It looks like the Pi
> > needs battery backup as this problem has not reared it's head on battery
> > powered systems.)
> >
> > Just wanted to pass information if you ever encountered this issue.
> >
> > 73 and aloha
> >
> > Dave - AH6OD
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> >
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