Raspberry Pi 3
SD Card: Samsung EVO Plus, 32Gb
Power Supply: 5v@2.4a
OS: Raspbian, Jessie
dist-upgrade 10/21/16
USB: WiFi Dual Band Adapter - https://www.amazon.com/TP-LINK-TL-WDN42 ... ss+adapter
Project (did I get this right?): Dual Band Mode with hostapd.
Opening comments:
1) Works out of the box in client mode, 2.4 and 5 GHz.
2) Excellent appearance. Nice!
3) 3' usb cable for optimum placement.
4) I would add shrink tubing at the usb to adapter connection.
5) Runs cool to the touch.
6) I suspect the adapter has one radio. Waiting confirmation from tech support but, we know this is the case.
The not so good part, Raspbian, Jessie:
Going from memory here but, this is reproducible. Ran through it three times.
1) AP already established, 2.4 GHz on motherboard, with hostapd. Excellent performance!
2) Power down and add adapter.
3) Client mode operates as expected.
4) "Turn Off WiFi". All WiFi dead.
5) Power down, hard boot.
6) Remove WiFi adapter cable.
7) Power up and origional AP is dead! Toggle on and off, dead.
8) Power down, hard boot.
9) Re-install usb cable and power up.
10) Motherboard AP back on-line. Usb WiFi still dead.
11) Power down, hard boot.
12) All back on-line.
Most likely I will edit the trouble shooting but, some thing isn't right here. Inexperienced people will be chasing their tails needlessly. This isn't the TP-LINK TL-WDN4200.
I still need to work on AP mode with hostapd but, I got side tracked.