Have you update the latest radio FW? When I first flashed MeanROM there is a section in the OP for flashing the radios. Here is a copy paste from the OP...
Originally Posted by Husker Z
The 1.22.651.3 update comes with a firmware upgrade that upgrades the radio, PRI, etc. When running MeanROM ICS v1.4 or higher, the new firmware is not required, but it is recommended. Since the ROM will run with or without the firmware, you can install the latest version of MeanROM ICS and then install the firmware, or install the firmware first, then the ROM: order doesn't matter! What does matter is whether you are s-on (HTC unlocked) or s-off (LazyPanda). If you do run into trouble flashing the ROM first, however, try flashing the firmware (or radio) first to see if that solves the issue. So here's what you do:
Option 1 (s-on HTC unlocked): While there are other firmware bits in the latest RUU, people who are s-on can only update the radio at this time. For the 1.22.651.3 RUU, this appears to be OK and taking the radio firmware and not the PRI and other firmware bits seems to have little or no down side. So to update your radio firmware if you are HTC unlocked (s-on), flash this file from recovery. Because you are HTC unlocked (s-on) it is flashed from recovery just as you'd flash a ROM (using "install" from TWRP). You do not load this from the bootloader!
Option 2 (s-off LazyPanda): Because you are s-off, you can flash all firmware bits: radio, PRI, and all. Just take this file, rename it PJ75IMG.zip, and place it on the root of your sdcard2 partition. Then boot to the bootloader (power + voldown) and follow prompts. Don't forget to delete the file after you reboot.
I did option 2 and have not had any issue with signal loss in CM10. Might be worth a shot. Looks like links are missing in the copied content, so if you want the links to the files needed the visit the thread on XDA.
Also, how are you wiping prior to flashing? I have a Super Wipe zip file that I got from another user on XDA. Let me know if you want to try that. I always use that zip to wipe before I install a ROM. Might also be worth a shot.