H.B.
I know someone that has the Summer video monitor (not the handheld one, the bigger one) and has two cameras in two seperate rooms for her 2 boys. She says it works awesome and flips back and forth every 8-10 seconds or something from room to room. She had to order the 2nd camera on the Summer website when the baby was born.
** She did say that she had interference for a while and realized it was the cordless phones that were running at the same frequency that the monitor was trying to use...so they changed cordless phones and all is well now...
I have the handheld Summer and never have interference except when my cell phone is ringing or receiving a message....you might want to check the frequencies of other things running in your home.
Best wishes!