Wireless headphone triggers off after a few minutes

Hello, I recently bought a wireless headphones Sennheiser RS 120 II and they are really good, but the problem is that that the transmitter keeps turning off when there is no sound and I keep hearing a disturbing noise from the headphones. I've read somewhere that you have to set the volume up in the pc or tv and lower it in the headphones but the sound is already set at 100% and I don't know what to do, can anyone help me?

I have a Sennheiser TR120 wireless headphone. It "collects dust" as they have poor RF reception. I bought them to use in my recording studio but they are basically useless.

So... there is no way of fixing it? I put a sound on my mouse when I click something so that it stays connected most of the time. I wish there was a program or a low sound running that could keep it alive.