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SPOT Satellite Messenger - 3/16/08 version |
I bought a SPOT satellite messenger in January 2008, and I'll be telling about my experiences with it on this web page. My objective is neither to promote nor put down the SPOT but to discover its capabilities and limitations when used on a motorcycle when riding trails.
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What is SPOT? From their web page at findmespot.com we see: SPOT. The World's First Satellite Messenger. With the SPOT Satellite Messenger, you and your loved ones have peace of mind knowing help is always within reach. SPOT is the only device of its kind, using the GPS satellite network to acquire its coordinates, and then sending its location - with a link to Google Maps™ - and a pre-programmed message via a commercial satellite network. And unlike Personal Locator Beacons, SPOT does more than just call for help. Tracking your progress, checking in with loved ones, and non-emergency assistance are also available, all at the push of a button. And because it uses 100% satellite technology, SPOT works around the world - even where cell phones don't. |
I tested the tracking feature of my SPOT on several automobile trips around central Colorado, and it worked pretty much as advertised. So, I mounted it on the handlebars of my CRF230F and began testing it on the trail. I made the GPS/SPOT mounts from Kydex, a heat deformable thermoplastic. To heat the plastic, I use a Bic lighter for small areas and a propane torch for large areas. I use pop rivets to add strength where necessary. As I describe below, body position can mask the SPOT view of the southern sky. Many riders are aware of this, and are carrying the SPOT in the top pocket of a backpack or water pack. You can find out more about Kydex at kydex.com |
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On Wednesday, February 27, 2007, I rode at Texas Cr, an OHV area in central CO. I rode some dirt roads and a few ATV trails. SPOT is supposed to send a tracking message every 10 minutes (once activated). It didn't do such a great job on this ride. In the table, I show the actual times that a message was logged on my SPOT web account page. UTC time is shown; I really don't ride at night. |
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Here's a new table showing the time only (no lat/long). I've added a column showing 'Delta t', the time difference from the start time. Next, I've added a column showing time in 10 minute increments to make it easier to see when the 10 minute messages were expected to be logged. The next column shows which messages are missing. The last column, 'Analysis', shows the results of my analysis of each missing message.
Message summary:
I accept that some messages were lost because the SPOT was blocked from a southern view of the sky. But three messages were lost in open areas and among small trees (bold). |
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Have I explained the missing messages? Sometimes I rode north, and my body blocked the signal (SPOT looks low on the southern horizon). I was also riding in a fairly deep gulches during the ride. But the messages missed when I was riding in the open are not explained. This test had only 21 data points and is perhaps not a fair indication of what to expect from SPOT. Variables unknown to me may have had an effect that I was unable to account for. The small sample size may not represent normal SPOT performance.
I plan to do more testing while riding in different terrain and will post results as they become available.