[App_rpt-users] Allstar RTCM (Radio Thin Client Module) isnowavailable

Thu Dec 22 11:11:58 UTC 2011

Some observations:

You beat us to the punch, but that's OK.

We would call this a gateway, which is what most in the industry call it
and should give you greater traction on the commercial market. I would
also substitute "tcp/ip" for "internet" as a broader term that doesn't
scare people who see the Internet as a den of iniquity rife with malware
and trouble.

This device is still a computer, albeit a simplified one. Note that it
has a  reset button on it, just like the gateway that one of my clients
produces. Every once in a great while I need to hit that button, FYI. It
could be caused by a power glitch or excessive RF impinging on the box,
but overall they can be quite reliable, just not a panacea.

I have heard from commercial radio shop guys involved with setting up
simulcast 2-way LMR systems remark that simulcast systems were never
intended to have large interference (overlap) zones. They initially were
seen as ways to connect regions separated by geographical boundaries,
such as mountains. Then the salesmen just HAD to sell them to customers
on flat land, which is when the fun began in the days before we mere
peons could access accurate gps signals. 

Presumably gps synchronization solves most of the problems, but with
analog radio systems running 5KC deviation on UHF it actually worked a
little better to have the transmitter frequencies dithered a few Hertz
either way. Don't ask me why, but that's what the boys at the PEPCo
radio shop found out. Maybe there are better, newer findings these days.

Overall, I'm not a fan of simulcast transmitters, particularly in
amateur radio service where (I hope!) the users are technically savvy
enough to know when to switch to another repeater to extend coverage. If
you can make it work, then great!

Bote

W4NUD

From: Peter Elke
Sent: Thursday, 22 December, 2011 04:10
Subject: Re: [App_rpt-users] Allstar RTCM (Radio Thin Client Module)
isnowavailable

Hi Marshal,

We have been running two separate test projects with the module over the
last few weeks.  So far they seem very functional and cut down on node
management if your goal is “perma-link” nodes.

The first project is to take separate sites and merge them into one
frequency (and one big node).  At this point we have two of the eight
cut over and we have worked out the basic mechanics.  We use Micor
receivers and MSX100 transmitters (that may change).  The transmitters
are frequency locked using MSF5000 UHSO units with the reference source
being a GPS’s 10Mhz output.  The UHSO creates 14.4Mhz that is fed into
the MCX units.  In our testing it became very clear that all of the
radios need to be identical.

The voting is very cool, you can watch as is switches between the
receive sites (very quickly, multiple times in a 1 second period) and
the toggling goes unnoticed  on the repeater’s output.   

Our next phase is to create larger overlapping coverage area to see how
it sounds mixed by adding a third site in the middle of the current two.
At this point we don’t have much simulcast data, the overlap area is
quite small.

The other project is an upgrade to my portable Beagleboard node that I
use traveling.  The old version was an Astro portable driven by a LOX
board.  The Beagle had a USB WiFi to a Verizon hot spot box.  The
upgrade swaps out the beagle for a RTCM and makes the connection from
the road automatic.  To create the internet for the module the old USB
wifi was switched out for a Ubiquiti PicoStation set up as a bridge.
When there is cell coverage it works and when there is no cell coverage
it’s dead, simple, easy, no-dialing.  The first road test was today, all
went well other than some LTE Verizon problems.

Over all very cool stuff…

Pete WI6H…

From: app_rpt-users-bounces at ohnosec.org
[mailto:app_rpt-users-bounces at ohnosec.org] On Behalf Of Marshall Oldham
Sent: Wednesday, December 21, 2011 12:23 PM
To: 'Jim Duuuude'; 'app_rpt mailing list'
Subject: Re: [App_rpt-users] Allstar RTCM (Radio Thin Client Module)
isnowavailable

Jim, 

Okay so one server running Allstar node software at a central location
(like my house) can support a dozen RTCM's being used as "Generic"
conventional 

full duplex (repeaters) radio interfaces on far away hilltops even if I
do not want to use the RTCM GPS-Timing Multi receiver voting or
Simulcast Transmitter features?

As long as I have some sort of internet connection at the remote sites
back to my house?

If I understand this correctly this would mean that:

1) No cost of computer at the radio site.

2) No worry about the node computer locking up at the remote radio site
and having to reboot or reset it.

3) No cost other than the RTCM (Radio Thin Client Module) to setup an
Allstar node at the remote radio site. (no computer, no URI,  no Sound
FOB) 

4) If I use the RTCM (Radio Thin Client Module) I have the ability to
setup a normal Allstar node at the present time and then later if I want
to I can upgrade the hilltop 

for GPS-Timing Multi receiver voting and Simulcast Transmitter by simply
adding a GPS receiver at the site and reconfiguring the software.

If so, this seems like a pretty cool little piece of hardware! 

Marshall - ke6pcv    

  _____  

From: Jim Duuuude [mailto:telesistant at hotmail.com] 
Sent: Wednesday, December 21, 2011 11:52 AM
To: Marshall Oldham; app_rpt mailing list
Subject: RE: [App_rpt-users] Allstar RTCM (Radio Thin Client Module) is
nowavailable

Yeah, that's the general idea. The location of the Linux server running
app_rpt/Asterisk can be
more or less anywhere within Internet connectivity of all of the
receiver and/or transmitter sites.
Of course, "Internet" can mean either some sort of public Internet
connection, or a privately-provided
Internet connection (low-cost microwave link(s), etc).

The only limitation is that an RTCM/Voter module *must* be located on
the same LAN as the Linux
server, to at least provide a GPS-based timing reference. A system could
be set up with a server
located in some sort of datacenter "on the ground", and all the radios
could have an RTCM "on the
hill" with them, and as long as there is Internet connectivity of some
sort between each of them
and the server, the system will work nicely. That is providing that
there is an RTCM located at
the server location also (whether or not that particular RTCM has radio
hardware connected to it
or not).

One minimal Linux server can easily support 1 or 2 dozen RTCM's (on 1 or
2 allstar nodes),
and a larger server could easily support MANY dozens of them on dozens
of allstar nodes.
Of course, you REALLY dont want to put too many of them on a single
server, being a potential
single point of failure. For pretty much any practical purpose, the
reasonable limitation is
the point of failure/redundancy issue, not technical limitations.

I'm not sure if you were clear on this, so I thought I would mention
that the RTCM is not just
usable as a GPS-timing-based Multi-Receiver Voting system and/or a
Simulcast Transmitter system.
It can also be used as a "generic" radio interface for a conventional
(non-GPS-based) either simplex
or full duplex (repeater) radio. The advantage of doing this would be to
not have the Linux
host "on the hill" with the radio (as mentioned above). In addition, the
RTCM allows for 
portable/mobile operation with a mobile/portable Internet connection in
both the GPS-based
and non-GPS-based environments. 

JIM WB6NIL

  _____  

From: ke6pcv at cal-net.org
To: app_rpt-users at ohnosec.org
Date: Wed, 21 Dec 2011 10:54:18 -0800
Subject: Re: [App_rpt-users] Allstar RTCM (Radio Thin Client Module) is
nowavailable

I have been looking at the Allstar RTCM (Radio Thin Client Module) and
it really looks like a GREAT product and addition to the already cool
Allstar hardware. 

Among all the other cool features of the RTCM (Radio Thin Client Module)
like Transmitter Simulcasting and Receiver Voting, if I understand the
documentation 

correctly you can use this very small Radio Thin Client Module at a
remote radio site to set up an Allstar repeater node if the site has
internet connection without a COMPUTER at the site?

Then you can point the node on the hilltop back to a server on the
ground somewhere that is easy to get too? 

How many total sites can you use Radio Thin Client Modules on and point
back to a single server on the ground?  

If this is the case, All I can say is WOW, how cool!

73

Marshall 

  _____  

From: app_rpt-users-bounces at ohnosec.org
[mailto:app_rpt-users-bounces at ohnosec.org] On Behalf Of Mark Guibord
Sent: Sunday, December 18, 2011 11:03 AM
To: app_rpt-users at ohnosec.org
Subject: [App_rpt-users] Allstar RTCM (Radio Thin Client Module) is
nowavailable

Allstar RTCM Radio Thin-Client Module, an Open-Source VOIP-Based Voting
Multi-Receiver and Simulcast Transmit System is now available for
purchase. 

For more information visit http://micro-node.com/thin-m1.html 

Regards,
Mark Guibord
Micro-Node International

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