Convert a Mastr-IIE to pass P25 digital?

Chrisjz · Post by **Chrisjz** » Thu May 13, 2004 3:22 pm

Ok, I want to pose a question to you guys. Do you think it would be possibe to convert or modify a GE Mastr-IIE to pass P25 digital voice? I know by adding a GETC (General Electric Trunking Card) you can pass IMBE Provoice and AEGIS so there has to be some way to do it. I would like your opinions on this one because I have several Mastr-IIE's and a ASIII along with a bunch of friends with XTS3K's and it would be nice to use P25 through the repeaters.

Post by **wavetar** » Thu May 13, 2004 4:00 pm

I think you meant 'GE Provoice', as IMBE is P25. I do recall somebody posting quite a while ago that MasterII's had been used to pass IMBE, but have no idea of the details.

Todd

Post by **HumHead** » Thu May 13, 2004 7:31 pm

It is my understanding that ProVoice uses the IMBE vocoder, but is not P25 compliant in terms of its modulation or error-checking formats.

Chrisjz · Post by **Chrisjz** » Fri May 14, 2004 3:13 am

That is correct about Provoice, it is not CAI compliant.

kb8gvq · Post by **kb8gvq** » Wed Jun 02, 2004 8:44 pm

In theory, just about any digital capable transmitter and receiver can do P25. In practice it may be more difficult than it is worth. Most Mastr III's can be converted to P25 with an available upgrade kit, but it includes a dsp board which has no dedicated slot on a MIIE. Current MIII stations can be converted with a simpler kit as provisions in the station for P25 have been implemented..Older ones take more including potentially the backplane...
Doug KB8GVQ

Chrisjz · Post by **Chrisjz** » Tue Jun 08, 2004 4:15 pm

Well, my question about making a Mastr IIE pass P25 does not invlove the use of a DSP module. What I am looking to do is pass-through P25 repeat. I know the newer Mastr III's out of M/A-COM are able to be upgraded with the addition of a DSP module. There must be a way to do this since a Mastr IIE can pass EDACS signaling and DPL. I guess it will take some more playing around to make the audio flat and bypass the pre/de-emphasis.