[App_rpt-users] RTCM Simulcast and 9.6 MHz Phase locking

Pierre Martel petem001 at gmail.com
Sun May 7 15:25:45 EDT 2017

I am very interrested in all this project. My email is VE2PF @ VE2MRC dot

what radio did you used for the project?

Thanks for sharing!


2017-05-07 12:32 GMT-04:00 Kevin Custer <kuggie at kuggie.com>:

> Joe,
> Why not consider do it as an article for Repeater Builder?
> Thanks,
> Kevin
> On 5/7/2017 3:13 AM, Joe Moskalski wrote:
>> I wanted to throw this email out to the group for all those who want to
>> simulcast with the RTCM. For those who don't know, in order to make the
>> RTCM suitable for simulcast you must have a more accurate 9.6 MHz clock for
>> the RTCM in order to ensure the audio sounds acceptable in the overlap
>> areas. I did this a few months ago using 9.6 MHz OCXO's. This worked
>> reasonably well. Not as well as I would have liked but the system was very
>> usable, but of course I wanted it to be better. Since the PCGM
>> (Programmable Clock Generation Module) is no longer available, I decided to
>> roll my own as some say.
>> I created a PLL circuit that can accept a 10 MHz, 1 MHz or 100 KHz
>> reference input and produce a phase locked 9.6 MHz out for the RTCM. I have
>> been testing this over the past few days and it has made an great
>> improvement in the audio quality in the overlap. The quality of the audio
>> in the overlap areas sounds very, very good, it's very similar to what I
>> expect to hear in commercial simulcast systems. My circuit is heavily based
>> off of an old Motorola MSF5000 HSO PLL circuit that I was able to adapt and
>> modify to my needs.  There are other uses for this circuit that make it
>> attractive for simulcasting but I wont get into them here. I am will to
>> share my schematic and bill of materials (digikey) with anyone. Please send
>> me an email and I will be willing to share all of my information on the
>> project.
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