That may be the case, but my signal strength bars (i.e. 3G signal) stay visible along with my wifi strength bars, so with wifi on my 3G doesn't seem to disappear.
I guess my question is whether the phone automatically chooses the fastest available connection 3G/4G/wifi and bounces between them depending on what's available or strongest?
Your signal bars(the 4 vertical bars) will always show, whether your using Wifi, 3g or 4g. And yes, the 4 vertical bars are your cellular/3g signal strength.
But what I think your asking is if you leave all of your radios on how dose the evo decide what Conection to use. I asked myself this a few weeks ago so on a day off I paid attention to how my wifi and 3G were connecting while I ran some errands around town.
I left my wifi and 3G radios on and while I was in my house where I get crap 3G and great wifi, it was on wifi. Left the house and out of range of my home wifi it jumped to 3g. Then I stopped by a local Starbucks where I have there hotspot remembered and I get great 3G signal, my evo hopped on wifi.
After that I went to a Barnes & Nobles, the whole time I was walking there I was connected to 3G. Got to B&N's where I get good 3G and have there wifi remembered it jumped on wifi.
Then I walked to my wife's office, the whole time on 3g. Got to her office and jumped right on her office wifi. Granted their is almost no 3G signal.
But just from doing that I get the feeling the our evo's will always go for a wifi connection when ever there is a opened and previously remembered wifi hotspot available.
Don't know about 4G(my rom doesn't support it) but I would have to think that it would be the same.
If you see the "3G" symbol with the up down arrows, your connected to 3G data. If you see the wifi your connected to wifi and so on.
Sent From My Miui Haven, Gingerbread Throwing eVo4g