Here's a couple posts from NastyNate208 that might shed some light on 3G issues. From Sprint Comm. forums....................
"For everyone comparing the signal indicator to the EVO/Epic/Shift/etc.. remember that the Nexus S has a "true" mobile network indicator. So when the NS4G shows 1X and the EVO(or other device) shows 3G, its simply because the EVO does not indicate the correct network technology, it always says "3G".
Also, AOSP devices (NS4G) have a different algorithm for calculating the signal, its more of an underestimation (in laymans terms). The NS4G also only has 4 indicator bars where the EVO/Shift/etc has 7.
These are just factors to take into consideration.
I also have the NS4G (since launch) and have experienced this issue to a small degree. Nothing worth returning the phone for though. What this phone has to offer is the rare instance of the Android Open Source Project, which is certainly not for everybody. So if this is a dealbreaker, return while you can. But take into consideration the facts provided above before doing so."
"Whoah calm down everyone. I was simply stating facts regarding the signal reporting differences. I am not implying anyone is incorrect in what they are saying... Just trying to help.
After a little more investigation I believe the issue is being caused by the Samsung driver build. I am quite certain its not the Sprint network, which is good news for everyone because an OTA can easily fix this.
However I encourage everyone to do the following as no company is going to fix an issue because people are crying on a forum. We need to give some numbers. If everyone in this thread gave the following info, Samsung/Sprint would have something to work with.
-Zip Code where issue occurs
-Build# (settings, about, bottom of page)
-dbm reading (setting, about, status, signal)
-baseband version (settings, about)
-83706
-GRJ22
-76dbm
-D720SPRKD8
Hopefully we will all have similar or the same reporting. Then when they look at this thread, it will prove this is not happening because a select few don't have the correct software or that we are just not having strong signal to begin with. The lower the dbm the stronger the microwave is (60-120 is the spectrum)
I encourage everyone to do this, then when we have 10-20 someone can forward this message to a tech."
Here's the link to Sprint Comm Forums......
Sprint Community: Signal Issues with Nexus S