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From: Bob Fraser on 17 Jun 2010 00:25
I am trying to research the full signal specs for the Motorola Project
(P) 25 "Astro" public safety trunk radio transceivers. This is the US
version of TETRA.

As far as I can find out, for phase 2, the carrier is 800MHz with
C4FM at 2.88KHz and a channel bandwidth of 6.25KHz.

Can anyone confirm this or provide more complete information of the
makeup of this signal?

Bob Fraser
From: miso on 17 Jun 2010 02:22
On Jun 16, 9:25 pm, bobfra...(a)protonet.com (Bob Fraser) wrote:
> I am trying to research the full signal specs for the Motorola Project
> (P) 25 "Astro" public safety trunk radio transceivers. This is the US
> version of TETRA.
>
> As far as I can find out, for phase 2,  the carrier is 800MHz  with
> C4FM at 2.88KHz and a channel bandwidth of 6.25KHz.
>
> Can anyone confirm this or provide more complete information of the
> makeup of this signal?
>
> Bob Fraser

The document is one of those damn things you have to buy. I understand
charging money in the dark ages when somebody actually had to print
the documents, but paying for PDFs is annoying.

You would probably do better putting a post on radioreference.com

Incidentally, I don't believe P25 is tetra.
From: Vladimir Vassilevsky on 17 Jun 2010 10:00


Bob Fraser wrote:
> I am trying to research the full signal specs for the Motorola Project
> (P) 25 "Astro" public safety trunk radio transceivers. This is the US
> version of TETRA.
>
> As far as I can find out, for phase 2, the carrier is 800MHz with
> C4FM at 2.88KHz and a channel bandwidth of 6.25KHz.

IIRC TETRA uses Pi/4 DQPSK with 4 timeslots per channel. The iDEN is US
system conceptually similar to TETRA. Physical layer of both systems is
based on that of DAMPS.

> Can anyone confirm this or provide more complete information of the
> makeup of this signal?
> Bob Fraser

VLV
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