[arm-allstar] Anyone running RTCM?

Sam Skolfield kj6qfs at gmail.com
Thu Sep 10 20:39:13 EST 2015


David,

The warble was bad with overlap ( sounded like CTCSS warbling, could have
been carrier)

A note to all - No matter how fast your "network" is ( all your stuff could
be on a table in front of you, with nothing but CAT-5 cables and an
ethernet switch), the TX buffer on the RTCM and voter.conf will not go low
enough for your users to "duplex" without echo. Period. People cried about
this on the main email group, and a firmware update was made for the RTCM
that lowered its minimum allowed TX buffer value, but it's still too high
to duplex.

That being said, the voting action with RTCMs is SUPERIOR! Works very well.
I have a system with several receivers scattered throughout a series of
mountainous canyons,  tied in with 900MHz and 5GHz and it works perfectly.
Using a BBB as a server.

73




On Thu, Sep 10, 2015 at 2:15 PM, David McGough <kb4fxc at inttek.net> wrote:

>
> Hi Sam,
>
> Just for my own curiosity, what was the problem with overlapping transmit
> sites? (I'm assuming the audio sync wasn't quite perfect?)
>
>
> 73, David KB4FXC
>
>
>
> On Thu, 10 Sep 2015, Sam Skolfield wrote:
>
> > It works, but not perfectly. If you have minimal overlap, it's
> acceptable,
> > but once your coverage starts to overlap, it gets hairy. Typical of any
> > simulcast system to a certain extent, but perhaps a little worse than
> > others.
> >
> > There is a high-level system that used to simulcast from two big mountain
> > tops using RTCMs (BIG overlap) and it was  really rough whenever you were
> > in earshot of both transmitters.
> >
> > I will say that the voting using RTCMS is absolutely fantastic. I have
> had
> > amazing results.
> >
> >
> >
> > On Thu, Sep 10, 2015 at 4:24 AM, Steve Wright <stevewrightnz at gmail.com>
> > wrote:
> >
> > > I just read that the RTCM simulcast multi-transmitter system actually
> > > DOESNT work.
> > >
> > > Can anyone shed light?
> > >
> > >
> > > S
> > >
> > > _______________________________________________
> > >
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> > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > > Visit the BBB and RPi2 web page - http://hamvoip.org
> > >
> >
> >
> >
> >
>
> _______________________________________________
>
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>
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>



-- 
KJ6QFS
Sam Skolfield
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