Hardware version A1
Located in USA
Factory reset performed before firmware upgrade to 1.30 and again after update
Only 2.4Ghz 802.11N used on main WiFi router and AP,
Main WiFi router signal is -80db on channel 1, this AP is on Ch 11, other WiFi signals in the area are weaker than -90db
There is a rarely used wireless DECT 6.0 house phone about 15ft away from the AP. There has been no correlation with phone use and AP problems,
Encryption is WPA2, AES, channel width 20Mhz, group key interval 1800, manual update
Short GI disabled, IGMP snooping disabled, connection limit disabled user limit is default value of 20 (there are about a dozen total , 1 Windows 7 laptop, Android and Apple pad computers and smartphones total that make occasional use of the AP.)
Intrusion detection disabled, QOS disabled,
Transmit power was 100% but changing it now to 50% per your guidance