Comments on: SiRFstar III reception under dense canopy http://gpstracklog.com/2006/08/sirfstar_iii_re.html GPS reviews, news, tips and tricks Wed, 23 May 2012 10:46:07 +0000 hourly 1 http://wordpress.org/?v= By: Rich Owings http://gpstracklog.com/2006/08/sirfstar_iii_re.html/comment-page-1#comment-108283 Rich Owings Mon, 25 Oct 2010 11:15:00 +0000 http://96.30.5.180/~gpstrac/2006/08/sirfstar-iii-reception-under-dense-canopy.html#comment-108283 The GPSMAP 60 and basic eTrex are older units without a high-sensitivity chipset/receiver. Newer models with this feature will dramatically improve your reception. An external antenna will likely also improve things but may not be necessary. You are correct that only the 62s and 62st support an external antenna, but not the 62. The GPSMAP 60 and basic eTrex are older units without a high-sensitivity chipset/receiver. Newer models with this feature will dramatically improve your reception.

An external antenna will likely also improve things but may not be necessary. You are correct that only the 62s and 62st support an external antenna, but not the 62.

]]> By: Daniel Austin http://gpstracklog.com/2006/08/sirfstar_iii_re.html/comment-page-1#comment-108117 Daniel Austin Mon, 25 Oct 2010 00:13:33 +0000 http://96.30.5.180/~gpstrac/2006/08/sirfstar-iii-reception-under-dense-canopy.html#comment-108117 I am a little confused about antennae and sensitivity under foliage, and would be grateful if you could clarify a couple of points that don't seem to be answered elsewhere. As a guidebook writer working in Africa, I use handheld GPS (generally on foot) both in urban and forest environments. I use GPS for various purposes, including producing maps for publication for which accuracy is obviously important. I started with the most basic Etrex, and soon upgraded to a GPSmap 60. I had expected the latter to be an improvement over the former with regard to its ability to get a signal under forest cover, but did not find it to be really significantly better. Walking along a forest trail, my GPSmap 60 rarely manages to be locked on for more than 10% of the time (which renders it useless for plotting trails or measuring trail lengths). Perhaps I am expecting too much and the types of forests I tend to visit are just too dense for GPS use? I don't know. What can I try to improve the situation? Both under foliage and not, I can sometimes get somewhat improved reception by walking with the unit held above my head, since my body is not shielding it from any direction. But clearly this looks ridiculous and is tiring over any distance! I have heard about external antennae, such as the GA-25MCX, which only ever seem to be mentioned in connection with vehicular use. I wonder if fixing a low-profile antenna extension to the top of my backpack (or hat) could bring benefits? I've never heard it suggested but it seems logical. My GPSmap 60 has now been damaged and I am considering replacing it with a GPSmap 62. In terms of ability under foliage, could I expect the GPSmap 62 to perform better than or broadly similar to the GPSmap 60? Also, could you confirm if external antennae are compatible with the GPSmap 62 (some websites suggest they are, but Garmin's own website only lists external antennae as accessories for the 62s and 62st, not 62). Many thanks! I am a little confused about antennae and sensitivity under foliage, and would be grateful if you could clarify a couple of points that don’t seem to be answered elsewhere. As a guidebook writer working in Africa, I use handheld GPS (generally on foot) both in urban and forest environments. I use GPS for various purposes, including producing maps for publication for which accuracy is obviously important.

I started with the most basic Etrex, and soon upgraded to a GPSmap 60. I had expected the latter to be an improvement over the former with regard to its ability to get a signal under forest cover, but did not find it to be really significantly better. Walking along a forest trail, my GPSmap 60 rarely manages to be locked on for more than 10% of the time (which renders it useless for plotting trails or measuring trail lengths). Perhaps I am expecting too much and the types of forests I tend to visit are just too dense for GPS use? I don’t know. What can I try to improve the situation?

Both under foliage and not, I can sometimes get somewhat improved reception by walking with the unit held above my head, since my body is not shielding it from any direction. But clearly this looks ridiculous and is tiring over any distance! I have heard about external antennae, such as the GA-25MCX, which only ever seem to be mentioned in connection with vehicular use. I wonder if fixing a low-profile antenna extension to the top of my backpack (or hat) could bring benefits? I’ve never heard it suggested but it seems logical.

My GPSmap 60 has now been damaged and I am considering replacing it with a GPSmap 62. In terms of ability under foliage, could I expect the GPSmap 62 to perform better than or broadly similar to the GPSmap 60? Also, could you confirm if external antennae are compatible with the GPSmap 62 (some websites suggest they are, but Garmin’s own website only lists external antennae as accessories for the 62s and 62st, not 62).

Many thanks!

]]> By: Rich Owings http://gpstracklog.com/2006/08/sirfstar_iii_re.html/comment-page-1#comment-84846 Rich Owings Sun, 11 Jul 2010 11:06:58 +0000 http://96.30.5.180/~gpstrac/2006/08/sirfstar-iii-reception-under-dense-canopy.html#comment-84846 Yes this is correct. The newer ones do not have SiRFstar III. Yes this is correct. The newer ones do not have SiRFstar III.

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