General Perceptions


E-Mail Jeff

If one were simply to read the GPS newsgroups, a person might easily come to the conclusion that the eTrex series of GPSR's can't obtain a satellite lock in any but the best of conditions, and that they can't record data accurately. You might also conclude that the Sportrak is unbelievably accurate, and that it doesn't suffer reception problems at all. What's the truth however?

Besides what I've read on the newsgroups, I've also found that when I've walked around the house while looking at signal strength bars on my GIII+, Sportrak, and eTrex, it appears that the eTrex is at a severe sensitivity disadvantage, while the Sportrak is somewhere just slightly below the GIII+ in sensitivity. Do the signal bars actually indicate how the receiver is doing however? I'm not sure, in part because when actually trying to navigate in reception problem areas, the eTrex seems to be the more accurate at displaying direction of travel, speed, and other such data. Whether this is a result of the software being better optimized for slow speeds and broken reception, or the reception being better than the sat status bars indicate I haven't a clue.

In addition to the navigation data the receivers provide me, I haven't found the differences in track recording ability to be what I would have expected. In fact, I've found that I can generally record accurate trail data more easily with my eTrex's than I can with my GIII+, or Sportrak. A big part of the reason for this is because the eTrex's shape and size make it easier to carry in an optimal way. Even when I carry the units optimally however, I don't see the eTrex as being at a significant disadvantage. When I do my side by side tests, the results end up pretty comparable most of the time, with the eTrex's more detailed track recording often providing much more accurate data than I can obtain with my other receivers.

In comparing my track log results, and when doing side by side comparisons with my hiking friends who use a variety of different receivers, it appears to me that the supposed differences regarding the reception ability of different receivers might not be as great as one would expect. In fact, I've found that most of the time when one of my receivers suffers reception problems, the other ones aren't doing so well either. From what I've seen, how you carry a receiver makes the biggest difference when it comes to recording tracklogs, or getting an accurate position fix, which to me equates to finding a receiver that fits your "style". I've also found that the accuracy of the position the receiver displays doesn't always correspond to what you would expect based on the satellite status bar page, and the displayed "Estimated error". With the eTrex, the satellite strength bars seem to be very conservative, resulting in the positional accuracy often being better than you would expect. With my GIII+, I often find my position is farther off than the sat screen would have me expect. The Sportrak I'm still trying to figure out. When recording a fixed position, it seems remarkably accurate. While on the move however, it seems to suffer somewhat compared to my eTrex, or GIII+

One thing to keep in mind when evaluating my perceptions is that most of the time my reception problems derive from terrain itself blocking satellite signal. Living in the dry state of Utah, I don't often have to deal with heavy broad leafed tree cover, so my experience in those conditions isn't great. From what I've been able to determine, pine trees don't generally cause much of a problem reception wise, nor do the aspens which are the primary broad leafed trees I encounter. Personality wise I'm not inclined to spend too much time or effort in trying to maximize the accuracy of my tracklogs. If it's something that's going to start interfering with my enjoyment of a hike, I'm not going to bother. Lugging around an excessively large, or awkward to carry unit isn't going to be an option for me, and since I often hike with my "young woman" daughter, looking too stupid isn't an option either. (She won't go if I embarrass her too bad) This rules out antennas on the hat brim, or long poles with antennas on top.

For what it's worth (A free opinion that is)