Default [Q] Signal temporarily dropping?

I used to be on ZV8 radios until about a week ago, when I flashed Optimus ROM and ZVA radios. I then had an issue where signal would drop for a few seconds and then reconnect. My cell standby shows 1% without a signal because of this. I flashed back to ZV8 radios, but I continue to get this issue even on AOSP ROMs. I might try to flash stock and update profile/PRL/etc, but barring that, any ideas as to what could be wrong? Thanks!
Phone: Google Nexus 5 "hammerhead" ROM: LiquidSmooth F2FS Kernel: ElementalX 1.00
Tablet: Amazon Kindle Fire (Gen 1) "otterx" ROM: CM11-F2FS by Hashcode
Tablet: Google Nexus 10 "manta" ROM: LiquidSmooth F2FS-All Kernel: KT-Manta F2FS-All
Retired: Sprint Motorola Photon 4G "sunfire", Sprint LG G2 "LS980"