In "Settings", "Wi-Fi" you should have "Ask to Join Networks" set to "OFF". Also disable BlueTooth if you use 2.4 GHz as it interferes with 2.4 GHz wireless.
If you really want to insure that a momentary wireless drop doesn't end up reconnecting on the wrong network you have to insure that your DL1608 network is the only one known to the iPad by:
In "Settings", "General", "Reset" you should "Reset Network Settings". This will reboot your iPad!
You can then connect to your DL1608 network (you will have to re-enter the Password).
Now if you have a momentary drop the iPad will always connect only to your DL1608 network
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You should make sure that you set your router to a clear channel if possible. In the States here we only have channels 1, 6, and 11 to use for 2.4 GHz. You'll need a laptop (running inSSIDer) or Android device (running WiFi Scanner) to scan for other routers as the @$$#*!#$ at Apple have banned WiFi scanners from their app store
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