low-cost aprs hardware - telus aprs hardware.pdf · aprs hardware using your existing ht with ......

Affordable, Low-Cost APRS Hardware

Using your Existing HT with the TinyTrak3 and the

Motorola i58srBy Fred Chen, VE7CX

05 January 2005

What Will Be Covered

• What is APRS?• APRS Applications• Types of APRS Stations• APRS Software and Internet Applications• Standard APRS Station• Compact Mobile Tracker• Low-Cost Mobile Tracker

What Will Be Covered

• Details of the VE7CX-9 Installation• Installation Tips• Other Mobile Tracker Examples

What is APRS?• Automatic Position Reporting System

(APRS)• Developed by Bob Bruninga WB4APR in

the early 1980’s• Used for tracking moving assets and digital

communications using GPS and 2-way radio

• Packet radio (e.g. AX.25 at 1200 bps on 144.390 MHz)

Types of APRS Stations

• Basic – transmit and receive (packet station)

• Relay – basic• Wide – basic digipeating• IGate – Internet gateways for

transferring packet data to the Internet• Tracker – transmit only

APRS Applications

• Static asset tracking (e.g. hospitals, EOCs, reception centres, digipeaters, my QTH, etc.)

• Tracking moving assets (e.g. vehicles, boats, aircraft, search-and-rescue teams, etc.)

• Experimentation• Just for the fun of it!

APRS Software• Provides near real-time tracking in

conjunction with a basic APRS station and computer

• Shareware programs and maps available on the Internet

• Windows (UI-View32, WinAPRS, APRS-CE)

• Macintosh (MacAPRS)• DOS (DOS-APRS)• Linux (Xastir)• Palm OS III (PalmAPRS)

APRS on the Internet

• findU.com


• Canadian APRS Network

What’s the Start-up Cost?

• Like any other hobby, there are extremes depending on your budget

• Some examples are shown in the upcoming slides

• Focus to towards affordable, low-cost options

• You may already own some of the equipment

Standard APRS Station

• 2-metre FM Transceiver (about $100 to $800)– Kenwood TH-D7A HT (Radioworld, $549)– Kenwood D-700A Mobile

(Radioworld, $799)– Deluxe models have built-in TNCs for APRS


• Full-featured TNC (about $130 to $300)– Kantronics KPC-3+ (Burnaby Radio, $299)– The older KPC-3 is also very good (about

$130 used)


• GPS Receiver (about $175 to $300, some over $500)– Garmin eTrex (Canadian Tire, $159.99)– Magellan SportTrak (Mountain

Equipment Co-op, $280)

Compact Mobile Tracker

• 2-metre FM Transceiver/Transmitter (we still need one of these…)

• Replace the TNC with a GPS Encoder– Byonics TinyTrak3 (Byonics, $38)– Tigertroncs TigerTrak TM-1+ ($120)

Compact Mobile Tracker• GPS Receiver (we still need one of these

too…mobile tracking will be very difficult without one!)

Low-Cost Mobile Tracker

• Goal is to keep cost to about $100 for the primary hardware

• Secondary hardware can be constructed by yourself

• Three main components still required are:1. 2-metre transmitter2. TNC or GPS Encoder3. GPS Receiver

Low-Cost Transceiver

• 2-metre FM Transceiver– Many good used HTs are available on

Ebay, eHam.net, and QTH.com for less than $80

– Any transmitter capable with an output of 1 watt or more on 144.390 MHz will work well (more power is better)

– Transmitter can be an HT or mobile radio

– You likely already own one!

Low-Cost Transceiver

• 2-metre FM HT– An Icom IC-2AT is recommended

because of its low-cost (about $35), it does the job well, and is readily availability on the used market

– Other good models are:• Radio Shack HTX-202

(about $65)• Yaesu, Kenwood, Alinco

2-metre FM HT Pricing

Low-Cost TNC

• Replace the TNC with a GPS Encoder • TinyTrak3 is recommended (Byonics,

$38)

TinyTrak without a case. TinyTrak in a homebrew case.

Low-Cost GPS Receiver

• Replace the standard GPS receiver with a Motorola i58sr GPS-enabled phone– Used (Ebay, about $35)– Brand new (Telus Mobility, $249.99

with no contract)

Motorola i58sr Pricing

Summary of Costs

• Standard APRS Station– Kenwood TH-D7A + GPS (about $710)– 2m HT + TNC + GPS (about $640)

• Compact Mobile Tracker– 2m HT + TT3 + GPS (about $400)

• Low-Cost Mobile Tracker– Used 2m HT + TT3 + used i58sr (about $100)

VE7CX-9 A Simple Plug-and-Play

Installation

Installing the Mobile Tracker

• 2-metre transmitter mounted underneath the dashboard with Velcro


• TinyTrak3 mounted underneath the steering column with Velcro


• Motorola i58sr mounted to the dashboard with Velcro


• Connecting everything together…– A serial data cable is required to connect

the i58sr to the TinyTrak

– A radio cable is required to connect the transmitter to the TinyTrak


• Master power switch installed within easy access of the user (driver)

Switch


• Simple quarter-wave mobile antenna installed using a NMO trunk lip mount


• Other secondary components to consider:– Anderson powerpoles (more on this

later)– Rocker switch for power (Radio Shack,

Part No. 275-712)– External DC power pack for the HT– DC charger for the i58sr– Dashboard mount for mobile phones– Industrial-grade Velcro tape

Setting up the TinyTrak• Software Configuration

Setting up the TinyTrak• Hardware Adjustments

– Adjust transmit audio level (requires a receiver…ask a friend for help)

• R6 potentiometer

– Adjust carrier detect base level (when the squelch opens)

• R9 potentiometer

– Calibrate for ceramic resonator error (default value of 128 is usually OK)

• Software

Setting up the i58sr• Setup GPS interface and configure

NMEA OUT to “On”

Setting up the i58sr• Obtain a position (your coordinates)

– Latitude and longitude (in degrees and minutes)

• Go to www.canaprs.net. or map.findU.com/<callsign-ssid> to see if you are being picked up by an APRS relay station and/or digipeater

• APRS coverage may be poor where you are (relocate and try again)

• Make sure the i58sr is still tracking satellites and sending NMEA data

• Operate in low RF environments (the TinyTrak is sensitive to high RF); talking on VE7RPT will temporarily disable the TinyTrak!

Does My Stuff Work?

Installation Tips

• Standardize your DC connections– Anderson Powerpoles (Durham Radio,

about $1.20 per connector)

– Saratoga PowerPanel 4 (Hamstop.com, $28)

Installation Tips

• Use wire loom to wrap around your DC wires for protection– Best place to buy it is from Lordco Auto

Parts (about 15 cents a foot)– Also available at Canadian Tire ($5.99

for 10 feet)

Other Ideas

• Consider also setting up an APRS relay station at home to improve APRS coverage in Greater Vancouver

• Use the AGW Packet Engine software to convert your computer soundcard to a TNC (a.k.a. soundcard packet)

Mobile Tracker Examples

Radio Shack HTX-202 HT, Delorme Tripmate GPS, and PacComm HandiPacket TNC.


Standard HX-340V HT, Magellan Trailblazer GPS, and TinyTrakII


Icom IC-2AT, Garmin eTrex, and TinyTrakII


Kenwood TH-D7A and Garmin eTrex (for pedestrian mobile tracking)


Alinco HT, Delorme Tripmate GPS, and Kantronics KPC-3


Launched by helium balloon and used for tracking and recovery teams

Alinco DJ-C1 Kantronics KPC-3+ (with cover removed)


• An integrated TinyTrak3 with 2-metre transmitter now available for $112

Resources• More details on the VE7CX-9 Installation

www3.telus.net/fredchen/aprs• TinyTrak3

www.byonics.com/tinytrak• Canadian APRS Network

www.canaprs.net• findU.com Network

map.findU.com• Northwest APRS Organization

www.nwaprs.org

Start Enjoying APRS Today!

My coordinates:• Telephone: 604-230-8083• E-mail: [email protected]• APRS: www.canaprs.net/ve7cx-9

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