I am a distributor for Sky & Technology equipment including the SRX-M8 receiver. This receiver has technology in it that no other manufacturer has and combines a host of different technologies in a single unit that makes it the most advanced receiver on the market today. Look for me at Toledo for a full demonstration.
You can program two transmitters at a time if you wish and use them as a cordless buddy box system or as a standby backup for the Primary transmitter. Those transmitters should be on different frequencies. You can switch from one to the other with the flick of the trainer switch.
The thing you were experiencing when you tried two transmitters on the same channel number is a unique feature that recognizes your master transmitter and then even if someone turns on accidentally it still only responds to the Master transmitter it was programmed to.
Some other unique features include a shorter antennae on the receiver which is allowed due to the unbelievable one microvolt sensitivity. Nobody and I mean nobody comes near this sensitivity. The list of high technologies goes on and on and you can see and purchase it at my website
www.4mht.com and I offer it at only $75. I'll see you at the larger trade shows but please check out the new Sky & Technology receiver at
www.4mht.com.