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Emtac S3 BTGPS Bluetooth GPS Receiver

By Legacy January 26, 2006, 12:00 am


I've been active in the world of handheld/PDA based GPS systems for a few years now, including beta tested a number of programs and reviewing hardware and software. It never fails to amaze me how far we've come in just a few short years. We've gone from bulky puck-type (mouse-type) receivers with thick cables — to thinner cables — to CF and SD type receivers that you just plug into an available slot on your PDA. More recently we're seeing an influx of Bluetooth devices. The appeal, of course, is that these devices require no external cables to connect your handheld to the GPS receiver. The Emtac S3 is one of the newest of these Bluetooth receivers. It offers a high-performance SiRFStar III-based receiver in a small, convenient package.


I've been working with the S3 for a little while now and I put it though some of the real-world paces that I put much of my hardware and software through. How did the S3 perform? Read on to find out...


The S3 BTGPS has a number of important specifications (especially the short acquisition times), some of the key ones are as follows:

It operates on L1, at 1575.42 MHz20 Channel all-in-view trackingProgrammable WAAS/EGNOSBuilt-in Lithium-Ion battery (650mAh) — lasts about 6 hoursAccurate to 10m (about 32 feet)Reacquisition time of 0.1 sec (average)Cold start time of <42 sec (average)Warm start time of <38 sec (average)Hot start time of <1 sec (average)50mm by 90mm by 17 mm (weight of 60g)


Because the S3 is based on the SiRFStarIII chip set, it has very fast signal acquisition times and improved performance in areas where the signal may be partially obscured — like a neighborhood with lots of trees, or the center of a large city with a lot of tall buildings. Also, this particular receiver is extremely small and thin, making it convenient to use in a wide range of settings.


The box contents include a carrying case, installation CD, and a variety of cables including a power adapter to plug it into a car lighter socket. The thing I found interesting is that there is no standard in-house AC adapter for charging it at home.

Included on the installation CD is the operating manual, some how-to's on BT pairing, and a trial version of Crux View to allow you to change and monitor some of the settings of the device.

As I mentioned earlier, the S3 features the SiRFStar III chipset, enabling quick signal acquisition and improved acquisition in partially obscured areas. In my use, I found that The Emtac S3 picked up the satellite signal very well, even in my driveway, where I often have satellite signal problems due to the dense foliage in my neighborhood. The S3 picked up the signal in under a minute from a cold start. My XTrac-based receiver could often take 10 minutes or more under the same conditions to pick up a signal!

Also in the package is a nice case for carrying the S3, but I have to admit that I don't use it much , because the S3 is pretty durable, not prone to scratching or scuffing.

The bottom has two rubber feet.

There are three LEDs which indicate battery life, Bluetooth status, and satellite link status. There's also a main on/off button, and port for the power adapter.

The first side has a port for an antenna extender (although I've never actually used this feature on any Bluetooth receivers I've used).

And on the other side, there's a clean edge.


Although the receiver is fairly easy to operate, some people may be unfamiliar with pairing a Bluetooth device and need assistance. The manual (included on CD only) goes through the process fairly well. The interesting thing, is that the receiver comes with a variety of cables and nowhere in the manual is there a list or description of enclosed items. Additionally, there are help files for Pocket PC 2003 and Windows Mobile 5.0, but no documentation for use with a laptop or Palm device. A Palm navigation bundle was available, but the documentation included in my evaluation was only for Pocket PC devices.

Another complaint I have about a number of newer GPS devices, this one included, is the lack of good information about using the WAAS/EGNOS capabilities of the SiRFStar III chipset. There is a pretty good description of basic GPS functionality in the documentation, and it does mention that you can use the included CruxView software (listed as a trial) to adjust settings within the receiver, it really doesn't talk much about WAAS/EGNOS or why you'd want to use those capabilities. For those who are interested, WAAS/EGNOS uses a combination of satellite information and ground station reference sites to improve the accuracy of your GPS signal to a degree better than the standard 10 meters. Many newer receivers can have this capability turned on or off, but not all software knows how to interpret the incoming messages. I would have liked to see more discussion of these capabilities in the documentation.


The only major complaint I had about the receiver was the on/off switch. It was small, extremely stiff, and rather difficult to operate. If it stuck out just a fraction of an inch further or was slightly larger, it would have been much easier to manipulate. As it was, I usually had to work it with my fingernail or a pen to switch the device on or off.

One problem that I've had with a lot of receivers in the past is that they can cause PDA lockups requiring at least a soft reset and sometimes even a hard reset. This happens because GPS receivers utilize the serial communications services of your PDA or laptop. Serial communications is one of the oldest ways that computers and peripherals communicate with each other. Serial communications are relatively simple and available on nearly all computers/handhelds, so are generally a popular and easy way to facilitate communications between devices. The problem with serial communications is that when they are interrupted, they often freeze up the connection and sometimes the entire device. This happens, sooner or later, on nearly all serial devices, including puck-type GPS receivers, CF/SD card-type GPS receivers, and even BT GPS receivers. The thing is, with Bluetooth, the serial connection is "virtual" — there is no physical, wired connection, so it might not be as obvious what went wrong. Some PDAs have a lot of trouble with their Bluetooth driver stacks. I am fortunate in that the BT stack on the devices I tested against (a HP Pocket PC, a Palm LifeDrive, and a Macintosh laptop) all were pretty stable and did well. I was impressed that in all the testing I did, the device had only one serial "burp" and that only froze up the application, not my PDA. So my wish for GPS receivers (while I'm going on this rant), would be a reset button to help when a serial freeze occurs. In the case of this device, there was only the one freeze-up, so such a thing becomes much less necessary. I'd still like to see a soft reset button for these devices, even one that seems to have very few serial problems, like the S3, especially since the on/off switch on this unit is so hard to operate.


The Emtac S3 BTGPS receiver is available at transplant GPS for $149.99. A WAAS enabled version is also available for $179.99.


  • Quick signal acquisition time, even in partially obscured areas
  • Small size
  • Rechargeable battery charges quickly and lasts more than 6 hours


  • No AC adapter for home charging

Documentation incomplete

Power switch difficult to operate


I like this receiver a lot and would highly recommend it. It's small, convenient, and has a reasonable operating time between charges. On top of that, it has fast signal acquisition times. I was pleased with how smoothly and cleanly it partnered with my devices and how well it operated with a variety of navigation programs. Despite the holes in the documentation and general lack of information on the topic of WAAS/EGNOS capabilities of the receiver, it has quickly replaced my CF-based GPS receiver and my puck-based receiver as my favorite GPS receiver.


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