Airplay Troubles! ZD1200, R700s, T300s, Apple Airport Express

[bryan_berkowitz]

Hi, I've got a ZD1200, 12 R700s, 2 T300s, and an Apple Airport Express. Everything is working nicely. When using airplay from my iPhone 6, The music streams well when I'm near one of the access points. When I'm in an area with limited wifi coverage - ~20db, 20% signal, it still works MOST of the time, but will occasionally glitch. It is very unreliable. Is there anything I can do improve the streaming, other than adding new access points? Looking to get this resolved, as it's been quite troublesome for this site. Thanks!

[michael_brado]

Hi Bryan,

Unless very densely deployed, your AP power will probably not be adjusted.  I suspect possible

interference.  If you save your AP support info file (from Monitor/Access Points, click the first icon

to the right of the target AP), and edit with NotePad/WordPad/NotePad++, look for the Athstats

radio 0 section, to analyze the 2.4G band.  There will be a Histogram, showing how many PHY

errors are seen during the rolling 2 minute sample period.  For example:

Histogram of PHY errors per second (pcttime in each range)
   0  1-500 ..1K  ..2K  ..5K ..10K ..20K ..50K .100K  more
   1      58     21    11      7      2        1        0         0        0

------------ Airtime Stats ------------
Airtime utilized (percent) since clearing delta stats (1 sec)
   Busy: 35    RX:  8    TX:  6    Total: 49
Histograms of airtime (pcttime in each range) since clearing all stats
          0  0-10  ..20  ..30  ..40  ..50  ..60  ..70  ..80  ..90 ..100
busy: 2    93     4     1     0     0     0     0     0     0     0
rx:     0    86    12     1     1     0     0     0     0     0     0
tx:     0    97     2     1     0     0     0     0     0     0     0
tot:    0    11    76     7     3     2     1     0     0     0     0

You don't want to see more than 2K PHY errors per second.  This example says 7% of packets

had 5K PHY errors, 2% had 10K PHY errors, 1% had 20K PHY errors, indicating a spike is seen

sometimes.  Overall, this AP shows 91% of packets are at or below 2K PHY errors seen, so fairly

low interference and relatively good 2.4G environment.

[bryan_berkowitz]

Here's what I've got on the AP in question:

------------ PHY Error Stats ------------815489 PHY errors since clearing all stats (rx_phyerr)
    710274 phy ofdm group
    105215 phy cck group
0 PHY errors since clearing delta stats (1 sec)
Histogram of PHY errors per second (pcttime in each range)
   0  1-500 ..1K  ..2K  ..5K ..10K ..20K ..50K .100K  more
   9    85     3     1     1     1     0     0     0     0

------------ Airtime Stats ------------
Airtime utilized (percent) since clearing delta stats (1 sec)
   Busy:  0    RX: 12    TX:  2    Total: 14 
Histograms of airtime (pcttime in each range) since clearing all stats
        0  0-10  ..20  ..30  ..40  ..50  ..60  ..70  ..80  ..90 ..100
busy:  91     9     0     0     0     0     0     0     0     0     0
rx:     6    85     5     2     1     0     0     0     0     0     0
tx:     0    96     2     1     0     0     0     0     0     0     0
tot:    0    84     9     2     1     1     1     1     0     0     0

how do I clear the stats? would like to do a clean test.

We are going to relocate one of the outdoor APs closer to the area with poor coverage. 

Currently in this area, the iphone will connect to either that outdoor AP, or the closest indoor AP.... both with weak signal. Hoping that by relocating it, it will be strong enough to connect. Is that a sound assumption?

[michael_brado]

Yes, that sounds like a logical next step.

[bryan_berkowitz]

What is a reasonable signal strength that I should expect airplay streaming to work with? And sometimes, signal strength shows up as N/A. What's the best metric to go by, the Signal (%), or AP Rx Signal (dB),  AP Tx Data Rate?

[bryan_berkowitz]

OK, we've relocated the T300 closer to the area that needs it the most and are now getting good streaming audio. Except for the case where we hold the phone close to our body, with our back towards the T300 (blocking it). I guess that's an extreme edge case though, probably nothing we can do about that right?