Thanks for all on the list who have given me a hand with getting the RTCM/voter boards running.

I currently have 1/3 of my system installed at the sites. It's as follows:

A TX only site - running a VOTER board, latest "Chuck" firmware. 9.6MHz OCXO replacing the onboard crystal and a 10MHz OCXO to keep the transmitter stable all on 53MHz.

On my bench at home I have an identical setup except with a receiver in addition. Both radios are the same, audio injected in the same spot.

I've been testing various frequency offsets to avoid the cancelling of the signal due to the inherent propagation effects at 6 metres. I've been able to run my bench radio into a dummy load and place it so that another radio nearby connected to an external antenna is receiving them almost the same (i.e. overlap). 

Currently 1-2Hz sounds the best. I have been encoding tone, however there is a very audible hum, as if the CTCSS tone from each transmitter is not in phase. The tone is 91.5Hz. I've checked/readjusted deviation levels etc, also checked the 9.6MHz OCXO etc but I cannot seem to null it out.

I've also tested the Simulcast Launch Delay.The main site is about 13 miles away, so I put a value of 330 in there to represent a delay of 66uS on the bench test radio. This makes a little bit of improvement, but not an overall huge improvement. Does anyone have an ideas that I've missed or more information on the usage of the Simulcast Launch delay?

Hayden