[arm-allstar] Anyone running RTCM?

[David McGough]

Hi Sam,

Thanks for the info. I figured that loud overlapping TX signals would
cause problems, even with the TX frequency synchronized.  I expect getting
a simulcast system working acceptably well on VHF, particularly low-band,
might be about impossible....I guess that's one advantage the higher 
frequencies (800MHz and above) have--controlling the antenna pattern and 
signal strength in any given direction is MUCH easier!

BTW, what band was were you all using? ...Again, just wondering. I'm 
building a wide coverage 10M repeater right now.

73, David KB4FXC


On Thu, 10 Sep 2015, Sam Skolfield wrote:

> 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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> > > >
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> > > >
> > >
> > >
> > >
> > >
> >
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> >
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> >
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> >
> 
> 
> 
>