[App_rpt-users] multicasting.

[Andrew Gilbett]

Jim,

Just a quick question, I am looking into simulcasting, can you please
explain what the 9.6MHz is for? is it for the RTCM internal clock or the
MSF5000? I thought the RTCM required only a 1PPS the get phase coherence of
the modulating signal.

I guess that this is the more general question about simulcast:

Phase coherence of the modulating signal is required.
Is phase coherence of the carrier required for FM simulcast or is locking
to a accurate frequency source sufficient? E.g. a rubidium oscillator,
which would give you frequency stability but not phase coherence.

Thanks
Andrew


Thanks :-)
Andrew Gilbett
andrew.gilbett at gmail.com


On 31 October 2013 13:03, Jim Duuuude <telesistant at hotmail.com> wrote:

> For simulcast ALL OF YOUR TRANSMITTERS NEED TO BE IDENTICAL (ELECTRICALLY).
>
> That means that they need to be the same model of transmitter, and TUNED
> to be
> identical as possible.
>
> So, you need to have the same model of MSF5000 at both sites. That's a
> darned good
> radio for this purpose.
>
> There needs to be a GPSDO (such as a Trimble Thunderbolt), and an RTCM at
> each transmitter
> site. There also needs to be an RTCM and GPS-based timing source
> physically on the same
> LAN as the host computer (which also might be one of the radio sites).
>
> Note, if you are intending to use a current model RTCM (or voter board)
> for simulcast, you
> will need to modify it for simulcast compatibility (which requires
> injection of external GPS-locked
> 9.6 MHz for the CPU), or wait until Mark comes out with the new version of
> the RTCM that includes
> the option for this built-in.
>
> Jim WB6NIL
>
> ------------------------------
> From: petem001 at hotmail.com
> To: app_rpt-users at ohnosec.org
> Date: Wed, 30 Oct 2013 15:20:15 -0400
> Subject: [App_rpt-users] multicasting.
>
>
>  Got a problem with one of my repeater.
>
> I live in Montreal QC, and as many of you know we are bless with a small
> mountain right in the middle of the city. (Mount-Royal) While if you have
> the blessing of having a repeater on top of it, the coverage is marvellous.
> (but I am not blessed at all!!!)
>
> So I have nice repeater to cover the north, east, and south of the city,
> but the damn mountain prevent me from covering properly the west part of
> the city.
>
> So I was looking at the rtcm to make a multicast/voter system on the other
> side of the mountain.
>
> I have a MSF5000 UHF at the main repeater site, would I be able to use
> that with the rtcm and I can have a TKR-820 as the remote repeater would I
> be able to use it too? Or I also have a Desktrac that used to be the UHF
> repeater before the MSF500 came along..
>
> What would I need to do make sure that its all stable? I think I would
> need at least 2 rtcm, But I would loose the dsp decoding of ctcss and
> squelch?
>
> Lots of question..
>
> Pierre
> VE2PF
>
>
>
>
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