The Garmin iQue M5 is one of only a few Pocket PCs to include an integrated GPS receiver which flips up from the back of the unit. Perhaps the best feature of the M5 is that it allows 3rd party software to access the GPS data stream. This includes Navzilla version 1.4.0 and higher. The official Garmin FAQs for the M5 say that NMEA data is delivered on COM2. On our unit, NMEA data from the built-in GPS is found on COM4 not COM2. Screen brightness of the M5 is good - not as bright as the very popular 396 and 496 units but the M5 is readable in direct sunlight. The M5 GPS is also more selective when it comes time to use a satellite with a marginal signal. The Haicom 303MMF (reviewed below) will include satellites with signal-to-noise ratios in the 20's. Where as the M5 GPS seems to only use satellites with an SNR of 30 or better. The high quality accessories include a USB / power base, car adapter with speaker, suction cup mount, power dongle and software. Since the M5 is primarily used for ground navigation, Garmin includes a version of MapSource in the box. Some sellers are also including the updated 2008 version of City Navigator. If you plan on using the M5 for road navigation, consider purchasing an SD memory card with at least 1GB of storage. It is possible to get an Internet connection when the M5 is paired with a compatible Bluetooth cell phone. One problem we had is that we are not able to make the connection using the connection dialog found at the top of the screen. To make a connection we have to run the BTExplorer application, select the cell phone in the Favorites list and then Connect from the menu.

Overall the M5 is an excellent value. Prices for overhauled units are around $270, less for used units sold by individuals. When Garmin announced the M5 in January 2005 the suggested retail price was $750!

The iPAQ 2215 (same as the 2210) belongs to a new generation of iPAQ PDAs. Gone are the bulky expansion sleeves, fixed batteries and dim screens. The 2215 is small, quick, easy to expand and priced right. The 2215 can accept compact flash cards directly without an expansion sleeve. The screen on the 2215 is bright and easy to read, however; like all PDAs we've tested, we wish direct sunlight viewing were better. The 2215 also has built-in Bluetooth (a wireless connection protocol). What does this mean? It means you can get an internet connection through your Bluetooth enabled cell phone and view Nexrad weather with a web browser on the 2215. We like anything that helps make weather information pervasive, easy and affordable. Battery life is good and the battery is user accessible. One gripe we have is with the data cable connection socket. This is where a data cable (like the one coming from your GPS) plugs into the iPAQ. The connector relies on two delicate little tabs to hold the connector in place. It is too easy to twist, rip and generally mangle this type of connector. If you're feeding NMEA data or power to your 2215 with a cable, keep an extra 9-pin connector in your gear bag.

Bluetooth GPS receivers are gaining popularity as PDA manufacturers scale back expansion slots options in newer models. The promise of a Bluetooth GPS is a wireless, no-tangle alternative to cables, both power and data. There are a number of things we really like about this receiver. Signal acquisition is excellent, the unit is small, easy to use (on or off) and has impressive battery life. On the first day we used the BT-308 we accidentally left the receiver on after doing a 40 minute software test . Six hours later we 'discovered' that the power had been left on so we just connected again and kept on testing. Line of sight range is about 25 feet, and this was achieved by carefully holding our testing PDA so as not to block reception. While doing this test we discovered that how the PDA is held can affect the quality of the Bluetooth connection. In fact, even when the PDA and GPS are just a couple of feet apart, placing a thumb over some areas of the PDA would result in a complete loss of connection. Anytime the Bluetooth connection was interupted the Bluetooth Connection Manager would pop up. We found this to be a nuisance and feel that the Connection Manager should make an effort to reconnect on its own. This behavior may vary from PDA to PDA. We also experienced a number of known Bluetooth bugs with our iPAQ. When the power is turned off with an active Bluetooth connection the PDA locks up and must be reset. Check with your manufacturer for a ROM update if you're having Bluetooth problems. Overall we were pleased with the BT-308 as a GPS receiver -- quick fix times and tracking of 9 or 10 satellites were typical. We were less impressed with the Bluetooth experience (not the fault of GlobalSat) and continue to favor hardware-to-hardware PDA/GPS solutions. While having a wireless GPS is cool, having a rock solid no-hassle CompactFlash GPS is way cool.

This compact flash gps receiver plugs directly into the compact flash socket of your PDA, eliminating the need for a cable between your PDA (or computer) and your GPS. Initially we were concerned that the reception capability wouldn't match the more traditional GPS units; however, the Haicom 303MMF has proven to be a very strong receiver. In fact, the 303MMF is the only receiver we've tested that tracks inside of our office building and away from windows. The 303MMF comes with a serial cable if you wish to use it as a mouse type gps. The 303MMF has a swivel between the compact flash card and the receiver pod. Positioning the receiver pod to be horizontal seems to work best. Some of you will recognize this unit as similar to a compact flash sold by "those other guys." Our understanding is that this is actually a newer version of that receiver and purchased from Semsons you save about $80 compared to what "those other guys" charge. If you're interested in learning more about compact flash GPS receivers we recommend GPSPassion.com.

The Holux GM-270 GPS is a popular receiver that plugs directly into the compact flash socket of your PDA. This model is one of the lowest cost options available. At the time of this review the GM-270 can be found for about $119. With a clear view of the sky this receiver performed well but did not track as many satellites as the Haicom HI-303MMF or the Garmin 35. We found the in-front position of the status LED distracting and we can only imagine it would be more so at night. Time to First Fix (TTFF) impressed us and seem slightly faster than the other units we've used. Unlike the HI-303MMF, the GM-270 does not pivot and that may explain why the GM-270 consistently "pulled in" fewer satellites. The non-pivoting design may prove to be more robust over the long run.

This older model iPAQ can give good service to value-conscious navigators. The going price for these Compaq made PDAs is about $120 plus or minus a few dollars. Add a $100 compact flash GPS receiver, a $39 Navzilla subscription and you'll have a color moving map for less than $260! Along with the low price comes low performance. We found the 3635 to be 2 to 4 times slower than the 2215 while performing basic navigation tasks. The 3635 uses an older style side light to illuminate the screen which is not as bright as those in the 3900 or 2200 series iPAQs. To its credit, the 3635 does have a very good 5-way button. The 3635 is also significantly larger than the 2215, add the compact flash expansion sleeve and the 3635 grows even more. (You may be able to find a special yoke mount expansion sleeve designed specifically for the 36xx series iPAQs.) If you decide to buy a used 3635 be sure it includes the original CD, compact flash expansion pack, documents and cables. Be prepared to replace the battery. Do-it-yourself battery kits can be found on eBay.

We expected more from the iPAQ 3975. The 400 MHZ XScale processor does little to juice performance on this device. In fact, some performance benchmarks show the 3975 as being significantly slower than earlier models of the iPAQ. Our 3975 has Pocket PC 2002 which has a reputation for being a little pokey. Despite its lackluster performace the 3975 will run Navzilla, just keep the display options at a modest level. Some users have been happy with an operating system upgrade to Pocket PC 2003. If you already have this model, give it try, otherwise, consider the iPAQ 2210/2215.

We like the Garmin 35. This is a receiver antenna only with a data cable that connects with your computer or PDA. The 35 continues to impress us with its ability to pull in satellite signals in locations where other receivers fail. It is not uncommon for us to see the 35 tracking 8 satellites while a consumer grade handheld sitting inches away from the 35 is only tracking 3. (Remember, it takes 3 or more to play.) The Garmin 35 is an excellent choice when performance is the primary objective. Garmin also supplies mounting kits and with screw holes on the bottom, you can easily build your own.

The Globalsat SD-501 is one of the first SD GPS units available on the market. This receiver is also sold as the i.Trek SD GPS. This receiver plugs into the Secure Digital slot found on many of the newer PDAs. The first thing we noticed is just how easy it is to plug in and out of the SD slot. In fact, it is much too easy! All it takes is a little bump and the spring loaded slot happily ejects the SD GPS. This is not the fault of the SD-501 but rather a design "feature" of the SD slot. While this might be desirable behavior for memory cards it seems to be a problem for cards that protrude beyond the normal form factor for an SD card. It is far too easy to accidentally bump and disengage the GPS unit in normal use. This is unlike any of the compact flash type GPS cards we've tested. The compact flash slot is not spring loaded and requires more effort to remove cards--that's a good thing.

The SD-501 requires the installation of a special driver that acts as a virtual COM port. While it seemed to work OK with most applications we tested (including Navzilla 1.3.3) we did have problems with the driver occasionally blocking the port. This required us to reboot our iPAQ a number of times to regain access to the driver-enabled virtual serial port. It should be noted that our version of the supplied driver was 1.0 -- hopefully future versions will be more stable.

In our opinion, this unit is well suited for a variety of ground applications such as in-car navigation or as a golf course assistant.

The Garmin eTrex Legend is a mid-range eTrex that represents a good price-feature point. The legend is a versatile device. Take it hiking, driving, or boating. Two alkaline AA batteries give good service and like all eTrex devices you can power the unit from an external source with the proper cable. Speaking of cables, the Legend comes with a cable that can connect directly to your computer or to your PDA with additional cables (or adaptors). While the eTrex is a fine GPS device it is by no means a replacement for the Garmin 35 in environments where reception performance is important. Some people keep a small battery powered GPS in their gear bag in case of a complete electrical failure. We think this is a good idea. For just over $100, a handheld GPS can get you within 100 feet of your destination in a pinch.

This cable from Gomadic gets the job done at a reasonable price. We like the built-in power lead that allows the iPAQ to be powered and recharged while the serial port is being used. The cable is about 10 inches long and has nuts that allow Garmin data cables (which have screws) to make a good physical connection. This cable is compatible with iPAQs in the 22/38/39/51/54/5500 series. Other than the single offered length we have been pleased with the Gomadic serial cable.