Rolla Regional Amateur Radio Society|
APRS Digipeater (WØGS-1) and IGate (WØGS-2)
The W0GS APRS digipeater (-1) and iGate (-2) are no longer in service.
Rolla area APRS digipeater and iGate services will be provided by the Missouri S&T
Amateur Radio Club (W0EEE). Check the
W0EEE web site for information.
This page is here for historical information only.
(1 June 2014)
The Rolla Regional Amateur Radio Society supports an Automatic Position
Reporting System (APRS)
digital repeater (digipeater), and associated
Internet Gateway (IGate) in Rolla.
The WØGS-1 digipeater
and WØGS-2 IGate are both registered with the Kansas City APRS
Organization. The KCAPRS web page shows a list of
"coordinated" digipeaters and IGates. Note that this
"coordination" is not as formal as it is with voice repeaters, but
serves as a repository of information about APRS systems in Missouri
Previous to early 2004, the Missouri University of Science & Technology (formerly UMR) Amateur
Radio Club (WØEEE)
sponsored a digipeater. However, the equipment was the personal
property of past club president, Ken (KC9UMR), which he needed to
he graduated. Looking at a map of APRS stations and digipeaters
around the state
of Missouri, it was clear that there was a void in the south-central
between the metropolitan areas of St. Louis, Columbia/Jefferson City,
and Springfield. Particularly, there was very little coverage
along Interstate-44 between St. Louis and Springfield for mobile APRS
stations. For this reason, in early 2004 the KCAPRS Organization
asked the RRARS if it could put an APRS digipeater into
place. The club had in its posession the necessary equipment to
implement a digipeater (thanks to generous donations from its
members). By May 2004, the digipeater was on the air, serving
passersby, and registered with the KCAPRS.
For packets to enter an IGate, they needed to be relayed to the nearest
IGate 90 miles away in Columbia (KMØR-1) through a digipeater
(KCØIRJ-3) 75 miles away in Jefferson City. This worked
well most of the time overnight, but frequently during the day when
2-meter propagation is at its minimum the packets would not make the
relay at KCØIRJ-3. By December 2004 it was clear that for
a reliable gateway to the Internet, it would be necessary to install an
IGate in Rolla. The WØGS-2 IGate was thus born.
The WØGS-1 digipeater runs on an old WinBook Pentium 150 MHz laptop
digipeater software, running on DR-DOS from a single bootable
3.5" 1.44 Mb floppy. No hard disk is involved. The laptop
interfaced with a Kantronics KPC-3 terminal node
controller (TNC), with
old pre-APRS firmware, running in KISS
mode. The radio is a Yaesu FT-2500M
transceiver, set to the standard APRS frequency of 144.390 MHz, and the
system is powered by a 12-volt gel cell, which is kept charged with a
10-amp DC power supply. The antenna is an omnidirectional
vertical. It is a Cushcraft
Ringo Ranger-II ARX-2B,
mounted atop the Chemistry building on the Missouri University of Science & Technology
campus. The antenna is approximately 70 feet in height above
average terrain (HAAT), the measured output of the FT-2500M is 40
watts, the feedline loss is .5 dB, and the antenna gain is 5.5 dBd
(yielding a total system gain of 5.0 dB). Hence, the
Power-Height-Gain (PHG) rating is 6350 (see the APRS PHG
calculator to see how this works).
A surplus Pentium-150 IBM
Thinkpad 560 was called into service to implement an IGate. The
system runs on Windows98 (second edition), running UI-View32 (2.03),
as a sound-card software TNC, with the audio from
WØGS-1 being fed to the microphone input on the laptop through a
Henry Radio Tempo S1
handie-talkie tuned to 144.390 MHz using the
built-in whip antenna. The UI-View software is configured as a
receive-only IGate, with no traffic being transmitted from the
Internet back into the local APRS network. Indeed, there is no
connection nor push-to-talk circuit even connected between the laptop
and the Tempo S1. Hence, the WØGS-2 IGate is
unidirectional, passing traffic only from RF to Internet.
APRS was developed by Bob Bruninga, WB4APR for use by
the Amateur Radio community. Please see Bob's APRS web page
for more details and history.
To see stations which have passed packets through the WØGS-2 IGate (or
other IGates) to the Internet, look at the stations
near Rolla, MO page on http://www.findu.com. You can also see these stations
in a graphical map format at the FindU web site.
View the status of the WØGS-2 IGate through its own built-in
web server, and view packet traffic analysis.