November 2010

Recently I got two up-to-date handheld GPS units conceived for the hikers: the Delorme PN60w and the Garmin 62s. I put them to a test, side by side, in the urban environment of a typical Italian old medieval city (old buildings built with very massive brick walls). These units belong to the new generation of handheld GPS devices capable of displaying custom raster maps.

The Delorme PN60w has some remarkable features but it is clearly conceived for the North American marked in mind. Actually it is not marketed in Italy. You have to order it on the Internet from the USA and pay the extra cost of the custom taxes.

Notwithstanding is pretty small screen, the Delorme PN60w is a well-built unit with a very pleasant interface. From an operational point of view it is very similar to the Garmin of the 60 series. It accept SD cards, not micro-SD, and this is a plus. It comes with rechargeable lithium-ion batteries. It can be paired with a device allowing sms messaging through the SPOT satellites that unfortunately works only in the North America (for commercial reasons, not for technical difficulties). Thus, one of the most advanced features of the device can not be exploited by the possible European customer.

After extensive testing of the Delorme PN60w I can confirm that it does not receive the EGNOS satellites (the European equivalent of the WAAS satellites) because the EGNOS protocol of data sending is not implemented in the firmware. This is a very strange choice because the US adventurous customer is not supposed to travel in the USA only (or he is supposed?). In our opinion a good GPS device conceived for the experienced hiker should work the same all over the World. This feature alone could be enough to convince the European customer to not purchase a Delorme. However I found a reason to do an incursion in the Delorme field because of its advertised unlimited capabilities of loading raster maps of any kind and format and even hybrid maps (raster + vector). I understood it worked according to the principles of a modern GIS sofware. Unfortunately the Xmap Professional mapping software necessary to upload raster maps to the device require the most powerful updated PC it is possible (you can not use a net-book). Very strangely the generated files are much bigger than the uncompressed original files. After generating map-packages I discovered that an originally small geotiff raster map was incredibly inflated in size! Anyway, the real problem with the PN60w is its very poor sensitivity. In urban canyons environment, most of the time the Delorme does not get a fix. Compared to a Garmin CSX 60 or Garmin 62s the Delorme is put to shame. The weakness of the Delorme (compared to the Garmin 62s) is clearly the antenna. Here and there on the Delorme users' forum I found some complains about the Delorme loosing the signal in dense foliage. The Garmin (series 60) are known to get the fix even in the densest foliage (my old Garmin CSX60 did). Actually I can receive two satellites with the Garmin 62s when I sit near the window of my studio at home (a building with 3 meters thick walls) while the Delorme does not see any satellite. The reason is simple: the Delorme antenna is a patch antenna integrated into the device while the Garmin series 60 use a quadrifilar antenna (this is the real strength of the Garmin series 60). Contrary to the Garmin 62s, the Delorme does not have a connector for an external antenna. Therefore there is no way to improve the Delorme performances with an amplified antenna (and I can assure that a re-radiating antenna of the type available for handheld GPS units does not work very well). At the end of the day I cannot recommend the Delorme device to anybody really interested in serious hiking and exploring.

In the Garmin field nothing is all good or gold. The Garmin 62s graphic interface is not as good and clean as it is in the Garmin CSX60 (its forebear - still the best Garmin device I ever owned). It is good you can crate custom raster maps in the kmz Google Earth format. This format is basically tiled jpgs so there are around many free pieces of software capable of converting raster map to the format accepted by the unit. Unfortunately the capabilities to display raster maps of the Garmins are crippled by a software trick: although a common 2-giga sd-card can contains many hundreds of 1024x1024 jpg tiles, a global 100 limit is set for all the custom maps you can save to its micro SD card at a time!! Obviously this limit does not apply to the Bird-eye raster maps Garmin is trying to sell to his customers in a proprietary format! This 100 tiles limit is very annoying (more annoying than the annoying orange actually). You are compelled to carry with you multiple SD cards or alternatively you have to carry a PC to manage maps, a solution good for a one-day hike not for long autonomous hikes. We sincerely hope this hideous limit will be dropped by Garmin asap. Garmin, please, publish a firmware fix! Meanwhile we also hope for some hacker to provide a fix allowing the installation of a true file manager to effectively activate or deactivate single kmz custom maps.

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January 2008

PRM or "Private Radio Mobile", are presently very cheap and sold by tons in every store. They could be very useful especially for desert hikes. During EMERI-I, EMERI-II and EMERI-III expeditions, we used these lind of radios to spread over a very large area without loosing coordination. This equipment highly increased our efficiency and safety. The serious desert hiker should chose a high end model. With the EMERI-III expedition I tested the Midland G7. It is a dual band model (PRM+LPD) like many others but professionally built, i.e. featured by a solid shell and good ergonomics. The plus of this model consists of the possibility to increase the emitting power by a very simple modification (up to 3 Watt in PRM and up to 500 mWatt il LPD). Every radio-technicians will easily do the modification. As an alternative it is possible to buy an "export model" already empowered. Other pluses are the possibility to change the antenna with a 1/4 wavelength flexible antenna and to add a speaker-microphone accessory. The modified model cannot be used legally in Italy or in some other European countries but if you bring it to the most remote regions of the Sahara, who cares about RF emitting limits?

I used my Midland G7 mounted on the backpack, with the antenna high on my head and the microphone-speaker on the backpack shoulder strap. It worked very well and through the companions on the top of Mount Bagnold I was able to communicate from the Wadi Waddan outlet to the inner core of the Jebel Uweinat (i.e. Wadi Abd el Malik-Karkur Ibrahim). The performances were outstanding. The weigh is all in the four AAA batteries; the G7 proved to be the perfect choice for the desert hiker travelling with as many litres of water as possible on his backpack!

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