3.15.1.0b04 Issues

Is this in comparison to beta2 or 3.0.2?

The 7dBm lower received signal strength does not necessarily indicate it is a defect or a problem, this can be by design and an improvement.  let me explain...

This may be common when there are fairly strong signal.   The Ambient Noise Immunity (ANI) features in the driver purposely attenuates the signal to better handle and decode the data stream in noisy environments.  We have been digging into this ANI change in behavior with upgrade of OpenWRT (why we have a beta 04).   

The ANI logic follows error rates in the receiver and looks to minimize these error rates by tuning parameters, one of which is lowering  AGC (or received signal strength).  Unless you are noticing degradation in actually using the mesh network, or worse, a link no longer shows, then we've yet to known in this instance if there is a real problem of concern here.   One way to confirm, is to measure actual data thoughput across the link, then roll back to 3.0.2 and do the same to compare difference.

Follow-up update:   The signal strength calculated on these Atheros chips is measured in reference to the noise floor and is not an absolute measurement.  The ANI logic is controlling gain, sets levels affecting spurs, and weak-signal detection stuff.  It works along side noise floor calibrations.   Long story short, I see that triggering resets in these ANI levels and causing re-calibrations, the indicated received signal strength instantly changes, and sometimes dramatically,  by 10+ dBm.   It shouldn't be doing this, but it does.  Here's a good reference for anyone that wants to dig in further:  http://www.google.com/patents/US7245893  .   Things have certainly changed into this upgrade release of OpenWRT and signal strengths are determined or affected differently.   We have to be careful to compare with prior release.

Joe AE6XE

When I upgraded from 3.0.2 to AREDN B02, on my Airgrid M5 I noticed a 8+  db drop in my indicated signal strength on my established links. I also had to drop down to 10Mhz bandwidth where I was running 20Mhz reliably over a 35 mile path.  Noise floor is at -95 and I should be in the clear with regard to frequency.   What used to be a -70 signal (20Mhz b/w)  is now running around -78 (10 Mhz b/w).  I just upgraded this same unit from B02 to B04 and there appears to be no "improvement" in the indicated signal strength.

One thing that I did notice is that the units can now seem to operate down to a lower "spread" of S/N almost down to around 6 where it used to take around 15 to 20 db S/N in order for the link to perform reliably.  I'm thinking that nothing has really changed with regard to the signal strength and the decoding algorithms seem to be working better.  The proof in the pudding is obtaining overall reliability.

I have 3 more of the Airgrid units to update and I will report back if there are any different results.  Once I get all ends upgraded and stabilized I will attempt to change back to 20Mhz b/w and see what happens.

T.D.

I updated to beta 4 from beta 3 load on a airgrid M2 and it trashed my node.

Some very bizarre behavior:

• Still radiates as “Mesh Node”
• I can connect to it as a Wifi AP but can’t control it. 
• It says its IP is 192.168.1.1 if I connect direct via Ethernet but it won’t respond to a ping
• Won’t respond to the browser at that IP either
• It gives me an IP of 192.168.1.19 if I connect direct so it’s DHCP seems to work
• Won’t respond to 192.168.1.20 either
• Ran an IP scan tool and it says there is a Ubiquiti on 192.168.1.

I can try the reset, but it's up on the roof at the moment.

3 observations/questions regarding beta 4:

1) To confirm another post, I also experienced a change in signal level/noise floor on receive, using channel 1 (2412 Mhz) @ 20 Mhz when compared to BBHN 3.1.0. Noise floor improved from -88 to -95, maybe better (-95 seems to be about the lowest measurable threshold(?). However, weak signals got even weaker and often disappeared. A link I had at -75 now reads -85-90db. Wifi scans turn up less than half the previous hits. It's been hard to quantify the change in lq but it does not seem improved on weak signals. The kind of links we have available are currently less than pristine so we rely on being able to “qrp”. The above link is 2.5 miles and not fresnel zone clear. Bullet/dish on this end, AirGrid on the other. Hopefully our club can soon put something up on an area water tower.

2) So, as I continue to work with the beta 4 on other devices, I reverted the above link to BBHN 3.1.0. I had no success using the AREDN admin console for this, had to tftp the “factory” bin. AREDN's update screen did not recognize the BBHN factory bin and only partially completed the sysupgrade version. Is this normal or am I doing something wrong?

3) After reverting to BBHN 3.1.0 there “appears” to be some persistence regarding the receive signals levels left over from the AREDN beta 4 flash. Do some parameters carry over from that flash? Can I ssh into a file somewhere and reset? Maybe reinstall the BBHN or even the factory UBNT first? When a unit is flashed, does it read the noise in its present environment and calibrate the new firmware accordingly? I ask that because the original BBHN flash was done in the “shack” at ground level, in a much lower noise environment, -95db. When put up at 42 feet it dropped to -87-88db with the same install. When remotely flashed at 42 ft with AREDN it improved to -95 and stayed there when reverted to BBHN 3.1.0.

Any insight on the above would be appreciated, as well as any advice on improving an analytical technique to assist in beta testing. I'm fairly new at all this so the learning curve is still pretty steep!