Report on APRS in the Canterbury Area

Steve Davis ZL2UCX

Introduction

For some years now a number if Christchurch AREC Section members have been interested in APRS and making use of it for AREC activities. Development of the use of APRS continues, and in general it has been successful.

Use

We have made use of APRS mostly for sporting events, including Jet-Boat River Racing, where we track the radio equipped safety patrol boats, and for Car Rallies. Some development work continues to produce small light weigh trackers that can be carried by a person rather than a vehicle.

Equipment

All equipment in use belongs to members, and is made available for AREC activities. Some members have a number of trackers that they can make available for bigger events.

Trackers

For trackers a radio, a GPS and a TNC or modem device is required. A variety of equipment is in use, depending on what the owner had access to at the time.

Most existing trackers here in Christchurch use the MIM module, which is small and effective, but is rather expensive (~$200), some use TNCs however we are hoping to have a number of trackers using the TinyTrack I modem.

For GPS we have a number of older Trimble receivers in use, a few Garmin GPS-35s (~$500) and more recently we have a number of Talon NavMan receivers (from Auckland VHF group ~$200).

For radios we are mostly using Tait T500’s, a number have become available, they are reasonably rugged and a reasonable price. They also have enough room in them to install a MIM or TinyTrack internally.

We are hoping to have a kitset of the TinyTrack I available for around $50, which is cheaper than importing a TinyTrack II or a MIM. Development of this kit has been delayed due to problems with developing the PCB, however this is now getting closer to completion. Once these are available they will be promoted nationally.

Work is being done for the NZLSAR Communications Sub-Committee investigating the possible use of APRS technology for SAR in conjunction with the SAR Icom F3 radios. However there is some reluctance from the Police to spend money on “Amateur” systems, requiring a public tender process.

A continuing challenge is to make the trackers robust and reliable for the difficult environments that they get installed and operated in, we have had the occasional technical problem due to the environment, such as connections being broken or shaken loose, keeping RF out of the digital parts, and no lack of gear getting wet …

Digi-Peaters

We have established a fixed Digi-Peater on a dedicated frequency for APRS. The dedicated frequency is 144.575, which has been adopted as the national frequency for APRS use. This Digi is used for general APRS activity in the area as well as AREC events when it provides suitable coverage. At present this Digi is made up of private equipment, and is installed at the Branch 05 repeater site on Marley’s Hill. Alternative sites are being looked at to allow the traditional 144.65 digi to be reinstated at this site.

We have experimented with a number of different forms of portable digi-peaters, making use of traditional TNCs, “parrot” repeaters, and we are also experimenting with digi software running on small laptops, and looking at small the possibility of a small digi based on a PIC chip.

Base Stations and Maps

A number of our members have WinAPRS running on Laptops that they take into the field to, operate either from their own vehicle or from our dedicated communications vehicles.

We have a station acting as an Internet gateway allowing local APRS traffic to be seen on findu.com, or by stations running WinAPRS or UI-View with an Internet connection only.

Work is being done to look at establishing a Satellite Gateway for both PCSat and ISS.

We have a good collection of maps that have been put together for the local area, or for specific events. Including a good line/vector map for the Christchurch area, and a many image maps that have been scanned. We can also make use of many forms of image map and vector maps and convert them to APRS formats.

Future

I have started to work with portable APRS systems in the field using Pocket Computers, using an iPaq Pocket-PC. There are versions of APRS available for Win-CE and for Palm pocket computers, and some hams are using them for general APRS use.

As mentioned above work continues to make trackers smaller and more portable for use by individuals, either on foot, cycle, horseback, and also for SAR.

Work is also being done with Satellites such as PCSat and the ISS to provide wide area coverage at infrequent intervals. This is not so useful for most events, and probably not applicable to low power portable systems, but has merit for some applications.

General

Here in Canterbury for AREC we are mostly using WinAPRS, however there are some individuals in the area, and groups in other areas that are making use of UI-View. While there are various advantages and disadvantages of both they do offer reasonably similar functionality. Many of us like the ability of WinAPRS and other versions of APRS to use line/vector maps, where-as UI-View can only make use of large graphical maps.

The biggest problem is radio coverage, and this really depends on a network of DigiPeaters, and the use of portable digipeaters.