Have to reset (airplane mode) the phone everytime I use the internet.

I have a ZTE Quartz z797z and when I’m online…it drops me from 3G down to 1x ALL the time. if I’m receiving a text simultaneously…it kicks me down to 1x. I flip on airplane mode…then off,..and wait. if a car passes by our house…I’m back down to 1x. I’ve not watched a YouTube video from start to finish without airplane mode EVER… I’ve never encountered this problem with any other device. my husband has a little Alcatel and doesn’t have problems. is the cell signal antenna just a piece if crap? did they forget to install one…period???