WEBSITE OF THE YELLOWKNIFE AMATEUR RADIO SOCIETY

Yellowknife, Northwest Territories, CANADA

DP22tn

 

The Automatic Packet Reporting System (APRS) is an amateur radio system using digital communications in order to monitor and send telemetry within a certain area, real time.  Telemetry (remote sensing) is used in many fields but for amateur radio operators it can be used for weather stations, mobile tracking (on land, air or at sea) and so forth.  With the advent of GPS sensors time can be recorded accurately and the position of an object can be reported.  

Typically APRS data is collected at a remote site by sensors then it is converted into a digital stream and transmitted on an APRS frequency (in North America this is typically 144.390 MHz (in the lower 2 m band).  The data stream is received by a nearby station and relayed (that station is called a digipeater) for local consumption.  Eventually the data stream is injected into an APRS station that is connected to the Internet (so that station is called an APRS Internet System or APRS-IS) via an Internet connected receiver (IGate).  With the data sent to the Internet, it can be collected by all users and combined and plotted on a map.  

In the first image above we see APRS/IGate activity locally around Yellowknife on the afternoon of September 1, 2021.  The website is at www.aprs.fi and it automatically goes to the location that your IP address is at.  One can select on this map a satellite photo overlay or other types of map that show the relief of the terrain.  Some observations:

  • At the far northeast of Yellowknife is WX VE8WD-2 - this is the weather station of VE8WD on Prelude Lake about 20-30 km from Yellowknife. Time, temperature, pressure, windspeed and rain are all reported as is the digipeater VE8TEA in Yellowknife through which it is relayed.
  • At the most easterly station, CYZF we find a weather station based at Yellowknife airport.  While the weather data is similar to that of VE8WD-2, this station does not appear to be connected to any local digipeater or IGate but rather is APRS via TCPIP, which is an internet suite protocol.  We think it was set up by KK5WM at some point and that is why it is labelled as being associated with KK5WM.
  • Moving east across Yellownknife, we find VE8WD-11 with an "X" like indicator.  This is the IGate but it is not in operation at the moment as its Internet connection is disconnected.  If we open the Info we find location, altitude, course, speed, device and path information. Other associated stations and proximate stations are also reported. 
  • Moving south east, we find VE8TEA.  We find similar information but also the last path as reading - "VE8TEA>APDW13 via TCPIP*, qAC. T2USANW".  This station is not just a digipeater but is also acting as the temporary IGate.  
  • Moving to the north east, we find VE8PAT.  This station is at École St. Patrick School and is the Society's primary emergency operating location (our EOC).  It appears to be operational but it is not connected to the Internet as there is no TCPIP information.  This is a digipeater - hence its name YKDIGI.  In the list of nearby stations it identifies some other stations not on the map - VA3VML-7, VE8WD-1, VE8WD, VE8WD-7, VE8CK-N and VE6BRZ.  These stations report hearing YKDIGI on the air.  Some of these stations are local operators and some are visitors from out of town.  
  • Finally moving north, we find VE8SKI.  This is the weather station that we installed at the Yellowknife Ski Club in August 2021.  The second and third images above show the inside of the station.  It is similar in design to the Prelude Lake station VE8WD-2.

APRS data is used by amateurs in interesting applications including,

  • to track train movements and positions by AMTRACK, the American national railway system;
  • by boaters to allow their movements to be monitored;
  • by amateur radio operators conducting high altitude balloon experiments (and allowing them to recover the payloads when the fall back);
  • tracking animals;
  • tracking and relaying signals via satellites, including the International Space Station;
  • direction finding;
  • etc.

The limit is only constrained by the limits of the imagination.  One of our members is planning to construct an APRS compost monitor.

Sources: