Hi!
I use JR radios myself and have never since 1980 when JR first came out have had any trouble with them.
Have you checked your batteries, I recommend checking the voltage on each cell (You have either 4 or 5 cells in you package) under load. Easiest way to check is to push needles through the plastic wrapping and use a volt meter. the reading should be 1,25 volt on each cell...lower and you must do something...!

Over here in Europe where we use 35MHz, my JR radios all have a range of 100m with the transmitter antenna fully collapsed, pointing at the airplane and with the receiver antenna inside the airplane fuselage fully extended.
Less than that ...at around 50m and I know something is wrong. This has happened twice for me and all because of bad cells in a battery package.

Regards!
Jan K
Airracing products
Swedish MVVS distributor