Rolla Regional Amateur Radio Society
APRS Digipeater (WØGS-1) and IGate (WØGS-2)

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 and Kansas.

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 remove when 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 Missouri area 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 using DigiNed digipeater software, running on DR-DOS from a single bootable 3.5" 1.44 Mb floppy.  No hard disk is involved.  The laptop is 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 mobile 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), using AGWPE 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.

Web master contact: rrars@rollanet.org