I was able to improve the performance of using my iPhone 3GS with my home MicroCell. I want to share how I did it. It doesn't work perfectly, but it does work about 75% of the time now. This is a big improvement over the 30% success rate I was having.
The problem: Sometimes my iPhone connects and sometimes it doesn't.
My partial solution: I got a 25ft. internet cable (It comes with a 6ft. cable.) and an extention cord. I tried it in various locations in the room. After about 10 tries, I found the location (and heights) that worked best for me. It is now hanging from the ceiling in a corner of my home study room.
My iphone/microcell performance is now at an acceptable level. It would be nice if it worked near 100% of the time as one does in my office at work where I have another microcell but the same iPhone. I was about ready to give up and go to Verizon because of the microcell problems I was having at home ... an expensive move for me ... but now with a 75% success rate, I'm staying with AT&T ... at least for now.
I had called AT&T Tech Support numerous times, exhanged my original "defective" microcell for another unit that performed just as badly. I reviewed suggestions on this forum. etc. etc. and nothing seemed to work consistantly. The bottom line is that AT&T has done a terrible job with this device. It is very much influenced by location relative to the signals received from nearby cell towers. Why it works better near my ceiling than it does at desk level, I have no idea ... but it does.
So ... if you're having problems with your MicroCell and can't seem to find a good solution, get a long internet cable, an extension cord, and experiment with different locations/heights. It might be worth the effort/expense.
Lastly, a caveat ... Since the microcell unit works with the AT&T network, I can't be 100% sure that changing my unit's location was the primary reason for it's improved performance. Coincidently with moving my microcell to it's current "ceiling location", AT&T may have made changes to the microcell (by downloading new firmware/software) or made changes to it's nearby cell tower system, or ... who knows what else??? The only way for me to know for sure is to move the microcell back to it's original location that produced poor performance and see what happens ... but I'm done experimenting.
I had similar problems with dropouts during calls. After re-reading the User Manual for the umpteenth time, I noticed the disclaimer about keeping the Microcell away from other wireless devices. Right away I noticed that my cordless phone base had migrated across my desk to where it was within a foot of the Microcell. When I moved the cordless phone base further away to another table, the dropouts were much less frequent, but did not go away entirely. I planned to buy some longer cables for both someday to see if I could get better results by moving the Microcell even further away from everything else on my desk (wireless router, Bluetooth keyboard, cordless phone).
Then recently I started working on a project that used the DECT cordless phone system. When looking up the radio frequencies used by DECT, I noticed that the DECT cordless phones actually use a tiny slice of spectrum that is in the MIDDLE of the 3G band. Arrrrgh! My cordless phone was a DECT type, and it would be nearly impossible to prevent the DECT signals from interfering with the Microcell when the base unit periodically pinged the remote phones. Even 5 feet away was not nearly far enough away. I swapped the DECT cordless phone for an old 5GHz cordless phone, and now my dropouts have disappeared...at least for a few days so far.
Oddly enough, everything I was using was from ATT, and all came equipped with rather short cables. It is hard to get the DSL Wireless router, the Microcell, and the cordless phone far away from each other.