Subject: [NEXTEL-1] P25 Simulcast

From: [email-masked]
Date: Wed, 08 Oct 2003 12:10:50 -0400

-------- Original Message --------
From: Mark Hollingsworth <[email-masked]>
Subject:  P25 Simulcast

I'm trying to find out if anyone, anywhere had done a
P-25 Simulcast system, in VHF, conventional - straight
digital.

It seems there are huge multipath and bit error rate
problems (since P-25 is very succeptable to multipath,
that doesn't suprise me).
But I want to see if anyone has actually done it and
made it work.

So far, nobody at Motorola knows of one that works.

If we can find one, we would like to talk to the users
and see if it is usable.

Mark Hollingsworth

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From: [email-masked]
Date: Wed, 08 Oct 2003 14:14:28 -0400

-------- Original Message --------
From: "Denning, Donald" <[email-masked]>
Subject: Re:  P25 Simulcast

I think New Hampshire State Police tried it and finally gave up on it.

To the best of my knowledge they never could get it to work.

If you think about the physics, it is near impossible because you can
never align the subscriber unit to multiple bases and the skew kill you
at a bit rate that gives you usable audio.

Packetizing the data will fix this.

You can give NHSP radio a call. 603-271-3636. Ask for the radio shop.
Thy are pretty friendly. It is New Hampshire after all.

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From: [email-masked]
Date: Thu, 09 Oct 2003 15:12:20 -0400

-------- Original Message --------
   From: John Gilbert <[email-masked]>
Subject: RE: P25 Simulcast
     To:

Motorola P-25 trunked simulcast in the VHF and UHF bands is just becoming
available with the 6.3 system release in the time frame you mention. Motorola P-25
trunked simulcast at 800 MHz has been available since the 5.1 release in early
2001. The 1996 Motorola conventional release 3.0 (VHF/UHF/800 MHz) simulcast
offering was/is P-25 compliant.

John Gilbert

At 02:48 PM 10/9/03 -0400, you wrote:

> Motorola has had simulcast and voting with the earlier forms of digital but when
> one of our customers requested it a few months ago for a true P-25 system they
> were told that it would probably be available in Q4 of 03 or Q1 of 04.
> Apparently it is the 4 level modulation that makes it special but I certainly do
> not have all the details yet.
>
> John Wachter