I have 4 GPS’s connected to four XT09 modems, and they each transmit 10 times per second, about 80 bytes per transmission.I am using the “user” setting on the XT09 PKG. I do not use destination addresses, but simply transmit the data as it is received. I want 2 of the radios plus an additional one to listen to all 4 radios. However, due to the constraints of the GPS they all receive data from their GPS’s at the same time, and thus transmit at almost the same time. I find that not all data is being received and I assume it is because some of the modems want to transmit at the same time but cannot. I am changing my retries from 0 to 2 in the hops that this will correct the problem, but I am interested in any other settings I may need to change. simply, I want multiple transmitters to be received by multiple receivers, and 2 of the transmitters are also receivers.