A few days after the debacle with the Holux GPSlim 236 and its faulty Bluetooth Radio (I returned the unit to Expansys France for a refund), I got another SiRF III unit to replace it. This time it wasn’t a Holux product, but the more ‘conventional’ (perhaps the ‘standard’) GlobalSat BT-338.
Packaging, Accessories, Design
The BT-338 packaging is definitely cheaper than the Holux, and it lacks a warranty card, manual and the travel kit that the Holux unit did. It does come, however, with a black case for the GPS, a car charger, and an AC adaptor. The unit uses the 4mm ‘iPAQ style’ DC plug as opposed to the botched mini-USB the Holux used. It also comes with a drivers CD (that I have no use for).
In terms of packaging and accessories the Fortuna ClipOn wins hands down. It includes a splitter cable (y-cable), a lanyard, a transparent case, a car and AC charger. The splitter cable provided with the Fortuna has a standard USB connector at one end, so you can charge your unit from a powered USB port. This is an excellent feature that I sorely miss.
BT-338 itself is much nicer to hold than the Holux, albeit a bit larger and heavier. It also feels better built. It has a power button (as opposed to a switch) and supports auto-off after a timeout period in which there is no bluetooth connectivity. Compared to the Fortuna unit, it is smaller, lighter and seems better build too.
The included battery, although removable, is not Nokia-standard like the Fortuna. The GlobalSat claims to have a 17hr battery, an impressive claim nonetheless, compared to the 10 hours the Fortuna and Holux claim in their specifications.
Performance
I compared the new GlobalSat unit (SiRF III, 3.11) with my old Fortuna ClipOn GPS (SiRF Xtrac 2.02 mode), sitting side by side, indoors with a very minimal view of the sky. The GlobalSat took less than a minute to get a fix, and that with 10 satellites, while the Fortuna could not get past a single satellite for more than 20 minutes. At about 40 minutes the Fortuna had 3 satellites in view, but without a fix. At about an hour the Fortuna acquired a fix with 4 satellites.
T = 10 minutes
T = 60 minutes
Although I didn’t keep the Holux for long enough to make extensive tests on it, and while it was obviously defective, I believe that it performed slightly worse than the BT-338, both in terms of (Time To First Fix) TTFF and in terms of actual performance. Note that the Holux and Fortuna units have an antenna port (MMCX and MCX respectively), while the GlobalSat doesn’t. I guess it doesn’t need it — it is more sensitive that I would ever care for.
Epilogue
Bluetooth GPS receivers are becoming increasingly common due to the proliferation of PocketPC/Ultramobile Laptop/Smartphone units capable to connect and use GPS information. Most, if not all, such receivers in the market come from Taiwanese manufacturers, almost exclusively making use of chips by SiRF. While the quality of most receivers is below average and only slowly improving as those manufacturers/integrators acquire more experience and expertise in their field, they are quite cheap and perform admirably — at least when they are not defective.
The software used (and pictured) above is Pyxis for Mac OS X, aimed for release later this year along with a GPS service/framework for OS X.