RF remotes generally work this way: The originating signal is sent from the remote as RF (radio frequency.) In the case of the MX-950 in my theater that's 418MHz, a very stable and reliable frequency band.
By nature, propane is clear and contains no scent at all. For safety purposes propane. companies add a substance known as ethyl-mercaptan to the propane fuel. Ethyl-. mercaptan has a strong rotten egg, or skunk-like scent, which allows the consumer to. smell it in the case of a leak.
I have an exterior vented propane fireplace in a new home my wife and I bought. It sucks. It puts out a dinky little flame and within minutes the whole house smells like propane and I have to open the windows to air it out. I just had the tank filled (100 gallon propane tank) last May and I have only run the fireplace a total of ten minutes.