After much research into GPS Receivers and GPS Software for the Pocket PC, I have decided to purchase the GlobalSat BT-338 GPS Receiver to be used with OziExplorer and OziExplorer CE.

Although I have used a number of GPS devices at work in the past, this is my first device...

The features and Specifications outlined below are taken from the GPSOZ Website.

Features

• SiRF Star III high performance and low power consumption chipset
• Communication with Host platform Via Bluetooth Serial Port Profile
• Built-in ceramic patch antenna
• Superior sensitivity for urban canyon and foliage environment
• 3 LED to show the rechargeable Li-ion battery
• Operation time:17 hours, in continuous mode
• Bluetooth operation range:10 Meter
• WAAS ENGOS is supported.

Specifications

• Chipset - SiRF Star III
• Frequency - L1, 1575.42 MHz
• C/A code - 1.023 MHz chip rate
• Channels - 20 channel all-in-view tracking
• Antenna Type - Built-in Ceramic patch antenna
• Position - 10 meters, 2D RMS
• Velocity - 0.1 m/s
• Time - 1 us synchronized to GPS time
• Default - WGS-84 Acquisition Time (Open sky, stationary)
• Reacquisition - 0.1 sec., average
• Hot start - 1 sec., average
• Warm start - 38 sec., average
• Cold start - 42 sec., average
• Altitude - 18,000 meters (60,000 feet) max.
• Velocity - 515 meters/second (1000 knots) max.
• Acceleration - Less than 4g
• Jerk - 20 m/sec3
• Voltage - Rechargeable and removable battery with 5V DC input charging circuit
• Operation Time - Default 17 hours after fully recharged, in continuous mode & programmable >20 hours, in trickle power mode
• Connection - Communication with host platform via Bluetooth Serial Port Profile
• Protocol messages - NMEA-0183 output protocol
• Output format - GGA(1sec), GSA(5sec), GSV(5sec), RMC(1sec),VTG(1sec)
• Operating temperature - -20° to 60°C
• Humidity - 5% to 95% Non-condensing
• Dimension - 72.5mm x 40.4mm x 23mm

In The Box

The GlobalSat BT-338 from GPSOZ comes nicely presented and well packed with the following accessories:

• BT-338 Bluetooth GPS Receiver
• 1700 mAh Li-Ion Battery
• Mains Charger
• 12V Vehicle Charger
• Leather Carry Pouch
• CD containing User Manuals and Test Software

The Leather Carry Pouch safely houses the BT-338 firmly on your belt, and is a snug fit with the GPS Receiver.

Pairing

As per the included instructions, the BT-338 is paired to the Pocket PC in a simple and straightforward manner.  Once it was paired and the Pocket PC set to provide the serial port profile on Com Port 6, setting the port speed in OziExplorer to the required 38400 and sentence to GPRMC resulted in instant communication with the BT-338.

Test Drive

On my XDA Atom, with OziExplorer CE installed and some 720 MB of calibrated topographic maps, I was more than ready to test out the BT-338 anywhere in the state of New South Wales!  As usual, the device required a good charge to fill the large 1700 mAh battery.  For first time use (cold start), the BT-338 took a good 45 to 50 seconds to lock onto the overhead satellites (Green LED flashing = locked, solid green = no lock), but once locked, OziExplorer CE opened up the appropriate topographic map and displayed my current location.

The first test involved driving up to one of our radio communications sites nearby, logging the track, recording waypoints and comparing my location, speed, satellites used and altitude with the Garmin GPS III permanently mounted in our work 4WD.

• Location - The BT-338 indicated my position closely tracking the highway, while the Garmin GPS III showed my location to be about 50 to 60 meters further away.
• Speed - Both devices indicated the same speed, although the Garmin GPS III was at least 5 seconds behind the BT-338.  Saying this, the BT-338 seemed less than 1 or 2 seconds behind my actual movement and position.
• Satellites Used - On average, the BT-338 was tracking between 8 and 11 satellites, while the Garmin GPS III was lucky to be tracking 7 satellites.  Out of those being tracked, the BT-338 was using the majority of satellites, while the Garmin GPS III only once locked onto as many as 5 satellites for a few moments.
• Altitude - With two Garmin GPS devices locked and the BT-338 for testing, I found the BT-338 displaying an altitude consistantly 40 meters lower than both Garmin devices.  There was no difference in altitude between the Garmin GPS units.  This makes me wonder if the BT-338 is not as accurate as the Garmin units regarding altitude, or if both Garmin units are not as accurate as the BT-338...  The Garmin devices were only 12 channel receivers compared to the 20 channel receiver inside the BT-338.

The last test I had prepared is for signal sensitivity - an especially good test considering there are many canyons and steep sided valleys in Australia, complete with dense foliage on overhead trees.  Before I had figured out how to test the sensitivity, I arrived back at work and parked the truck under our large color-bond work bay.  As usual, both Garmin GPS devices sensed the vehicle about to park under a tin roof so displayed "Poor Satellite Coverage".  To my amazement, the BT-338 continued tracking 10 satellites with rock solid signal strangth!

I decided the test would be how many satellites (if any) the BT-338 would continue to track inside our workshop.  The results were too hard to believe.  After a good 30 minutes of indoor use, the BT-338 continued tracking more than 6 satellites, and also continued tracking my position as I walked around inside.  This is something I have never seen before.

I found it hard to believe the first test, so on a week-end decided to test it out inside the new Harvey Norman complex here in Dubbo.  At first, the BT-338 was tracking 8 satellites indoors with moderate signal strangth.  It wasn't until I moved to a location in the store with lots of solid objects above my head (concrete roof, tin roof, air conditioning units etc...) that the BT-338 dropped down to 3 satellites and indicated poor satellite coverage.

Conclusion

After some comparison tests with two different Garmin device models, the BT-338 performance simply knocks the socks off the others.  This unit is very easy to use, very affordable and has exceptional signal sensitivity.  The BT-338 works flawlessly with my XDA Atom (running WM5.0) and OziExplorer CE.  Battery life is terrific, as my last trip of 12 hours return didn't see the BT-338 indicate low battery at all.

If you are looking for a GPS receiver to go with your Pocket PC or Laptop computer, this device is the one to get.  I was contemplating going for a 12 channel device, but am very happy I purchased this device.

After looking around on the internet for an online store, I decided to give GPSOZ a try.  They have the BT-338 available for $285 AUD, and their service in my case has been excellent.  They were very helpful in answering my many questions, and after paying by Card over the phone, my new toy was here the very next day.  They also have many other GPS devices and accessories on their site.