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Old 11-26-2007, 10:35 AM   #46
offroute
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More Testing and Thoughts on SPOT

Did a 3.5 hour ride yesterday in mostly moderately dense pine forest. Single and double track. Had tracking on the entire time which means that it attempted to send approximately 21 TRACK POINTS. Twelve were sent successfully. This was on a brand new unit, not the demo unit I tested in the Death Valley report above.

I regard this success rate as pretty darn good considering the density of the tree cover. Interestingly, when I returned I forgot to turn the unit off and left it in my garage where it successfully transmitted a few points over the next few hours.

I consider the TRACK function a bonus. Of real importance is how the HELP and 9-1-1 functions would work in the real world. HELP transmits once every 5 minutes for an hour. 9-1-1 does the same for several hours. My guess is that with satellites moving around the sky, the user is likely to get a few successful messages out within SPOTS described coverage area. For those who want to get on OK Check-In message out, I recommend that they be careful to provide the clearest view of the sky possible since it only transmits that message once. I would not count on an OK message getting successfully transmitted 100% of the time.

I think its a great device and will own one myself - using it when I ride with others or when I don't anticipate being in heavy tree cover or steep canyons alone. In those cases I'll revert to a low freq 406 PLB and give up SPOTs advantages of Check In and HELP.

I agree with TomW that feedback from several other users in different parts of the country with give us a much clearer picture. I also need to reiterate that HELP and 9-1-1 operate differently than TRACK and it is likely they would be prove pretty darn reliable in most situations where a reasonable view of the sky is obtained.

Great to hear the feedback of others over time.
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Old 11-30-2007, 06:04 AM   #47
SpotMaker
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Quote:
Originally Posted by offroute
I consider the TRACK function a bonus. Of real importance is how the HELP and 9-1-1 functions would work in the real world. HELP transmits once every 5 minutes for an hour. 9-1-1 does the same for several hours. My guess is that with satellites moving around the sky, the user is likely to get a few successful messages out within SPOTS described coverage area. For those who want to get on OK Check-In message out, I recommend that they be careful to provide the clearest view of the sky possible since it only transmits that message once. I would not count on an OK message getting successfully transmitted 100% of the time.
Hi Adventure Riders!

I work for Axonn LLC, the company that designed and manufactures the SPoT. I am one of the engineers that designed it. I'm loving seeing the response that it is getting! Lots of folks seem to be excited about it.

Here are a few tips for it's use:

The "check in" message actually transmits THREE TIMES. It transmits in the following pattern: As soon as the SPoT has a GPS fix it transmits, then 5 to 10 minutes later (randomly dithered) it transmits a second time, then 5 to 10 minutes after that (random again), it transmits a third time. These three transmissions all have the same internal packet ID which causes the SPoT back office to throw out the duplicates and only send one to the emails and cel-phones on your check-in list.

As a result, this coverage map:

http://www.findmespot.com/explorespot/coverage.aspx

Shows the probability of a check-in message getting through!

How do you know when it's done sending all three messages? Simple, the "ok/check" LED stops blinking! So, it's best to send check-in messages from your base camp, or when you've stopped for a few minutes to admire a view. Activate check-in mode and leave the SPoT sitting with it's face to the sky until the ok/check LED stops blinking.

The coverage map also shows the probability of at least one out of any three consecutive help or 911 messages getting through (at 5 minute intervals, help and 911 will have transmitted 3 or 4 times in 20 minutes, depending on when you start measuring the time). Each help, 911, or track message is only sent once, but a new one, with fresh GPS data and a new packet ID (causing the SPoT back office to pump all of them through), is sent every 5 minutes for help/911 or every 10 minutes for track.

Offroute is exactly right in his assumptions as to what it means that the satellites are moving around in the sky. For a message to go through, at least one satellite has to see your SPoT, and see one of the SPoT ground stations! What this means is: if you've got a great horizon-to-horizon view of the sky, and you're not too close to the edge of the dark orange area in the coverage map, almost 100% of your "track", "help" or "911" messages will get through. If you have only a partial view of the sky, or you're starting to get near the edge of the dark orange area of the map, the condition of a satellite being in view of both your SPoT and the ground station happens somewhat less often, so fewer of your messages will get through.

But: since the satellites are moving around, time is your friend. If at one moment in time, there is no satellite in a "good" position for you, the odds are very good that 5 - 10 minutes later one will be! So, since the check-in message is actually transmitted three times, we've measured that throughout most of the US and Canada the probability that the check-in message will get through is around 99.99% (you'll miss something like 1 in 10,000). The likelihood that at least 1 out of any given 3 consecutive help, 911, or track messages will get through is about the same.

Again, thanks for all the great comments! We're real excited about our new product. Great to see others are too!
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Old 11-30-2007, 08:36 AM   #48
offroute
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Quote:
Originally Posted by SpotMaker
Hi Adventure Riders!

I work for Axonn LLC, the company that designed and manufactures the SPoT. I am one of the engineers that designed it. I'm loving seeing the response that it is getting! Lots of folks seem to be excited about it.

Here are a few tips for it's use:

The "check in" message actually transmits THREE TIMES. It transmits in the following pattern: As soon as the SPoT has a GPS fix it transmits, then 5 to 10 minutes later (randomly dithered) it transmits a second time, then 5 to 10 minutes after that (random again), it transmits a third time. These three transmissions all have the same internal packet ID which causes the SPoT back office to throw out the duplicates and only send one to the emails and cel-phones on your check-in list.

As a result, this coverage map:

http://www.findmespot.com/explorespot/coverage.aspx

Shows the probability of a check-in message getting through!

How do you know when it's done sending all three messages? Simple, the "ok/check" LED stops blinking! So, it's best to send check-in messages from your base camp, or when you've stopped for a few minutes to admire a view. Activate check-in mode and leave the SPoT sitting with it's face to the sky until the ok/check LED stops blinking.

The coverage map also shows the probability of at least one out of any three consecutive help or 911 messages getting through (at 5 minute intervals, help and 911 will have transmitted 3 or 4 times in 20 minutes, depending on when you start measuring the time). Each help, 911, or track message is only sent once, but a new one, with fresh GPS data and a new packet ID (causing the SPoT back office to pump all of them through), is sent every 5 minutes for help/911 or every 10 minutes for track.

Offroute is exactly right in his assumptions as to what it means that the satellites are moving around in the sky. For a message to go through, at least one satellite has to see your SPoT, and see one of the SPoT ground stations! What this means is: if you've got a great horizon-to-horizon view of the sky, and you're not too close to the edge of the dark orange area in the coverage map, almost 100% of your "track", "help" or "911" messages will get through. If you have only a partial view of the sky, or you're starting to get near the edge of the dark orange area of the map, the condition of a satellite being in view of both your SPoT and the ground station happens somewhat less often, so fewer of your messages will get through.

But: since the satellites are moving around, time is your friend. If at one moment in time, there is no satellite in a "good" position for you, the odds are very good that 5 - 10 minutes later one will be! So, since the check-in message is actually transmitted three times, we've measured that throughout most of the US and Canada the probability that the check-in message will get through is around 99.99% (you'll miss something like 1 in 10,000). The likelihood that at least 1 out of any given 3 consecutive help, 911, or track messages will get through is about the same.

Again, thanks for all the great comments! We're real excited about our new product. Great to see others are too!
This is great information. Thanks a bunch SpotMaker!
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Old 11-30-2007, 09:35 AM   #49
DRTBYK
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Howdy SpotMaker,

Thanks for joining in. Just wondering if you can give us some insight into increased coverage area? For example, when/if we might see better/any coverage in Kazakhstan (and the other "-stan" countries), IndoChina and Southern Africa. Will be testing SPOT in Japan, China, Russia and Ukraine next year. There would also be opportunity to test in IndoChina but I see no coverage there so most likely the SPOT won't be turned on.

One other point of interest to me is that the SPOT GPS satellite acquisition doesn't seem to be as sensitive as my newer GPS units of similar size. I am contributing this to GPS chip selection rather than antenna design choice. Any input?

Nice packaging over all and the price point is excellent. I would like to see more/better user options for handling of the data on the backend but maybe now the product is out there will be time/money to invest there.

Best of luck with SPOT. We need good tools.

Cheers,
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Old 11-30-2007, 10:33 AM   #50
SpotMaker
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Quote:
Originally Posted by DRTBYK
Howdy SpotMaker,

Thanks for joining in. Just wondering if you can give us some insight into increased coverage area? For example, when/if we might see better/any coverage in Kazakhstan (and the other "-stan" countries), IndoChina and Southern Africa. Will be testing SPOT in Japan, China, Russia and Ukraine next year. There would also be opportunity to test in IndoChina but I see no coverage there so most likely the SPOT won't be turned on.

One other point of interest to me is that the SPOT GPS satellite acquisition doesn't seem to be as sensitive as my newer GPS units of similar size. I am contributing this to GPS chip selection rather than antenna design choice. Any input?

Nice packaging over all and the price point is excellent. I would like to see more/better user options for handling of the data on the backend but maybe now the product is out there will be time/money to invest there.

Best of luck with SPOT. We need good tools.

Cheers,
I do not know what the schedule is for adding coverage and I strongly suspect that the schedule for adding coverage is proprietary so I wouldn't be allowed to divulge it even if I could get them to tell me.

Having said that, the building of new ground stations to increase coverage area is something that is going on, I just have no actual clue as to the schedule.

And having said that... if you're going to be in some of the fringe areas on the map I'd love to see reports of what sort of throughput you got in those areas! :)

As to the GPS acquisition time:

I do know in the most finest of detail as to why it is what it is, but those details are also proprietary, as you might have guessed.

However, I think I can make a generalized statement (without getting into trouble) as to why the acquisition times are slightly higher than the newest state-of-the-art GPS units:

In order to make the unit as 1)small, 2)light, 3)inexpensive and 4)power efficient as it is, some design choices were made that traded off raw acquisition time for smallness, price, and improved battery life.

There's also an internal delay of a total of 30 seconds after an actual GPS fix is obtained before we transmit for power management reasons. (So, when you see it transmit, it actually had a GPS fix 30 seconds prior.)

The satellite transmitter within the unit is a major power sucker when the messages are being transmitted to the satellite. This resulted in the other parts of the unit having to be extraordinarily power efficient to compensate.

The GPS subsystem in the SPoT uses an infinitesimal fraction of the power that the equivalent subsystem in a hand held GPS navigator uses, for example.

So, raw dead cold start on a SPoT is a little longer than the best of the newest GPS navigators.

What's a "dead cold start"?

That's when:
  • The unit hasn't obtained new almanac data from the GPS satellites for more than 30 days or,
  • The unit has been moved more than about 600 miles since the last time it obtained a fix.

However, warm and hot starts still take only a few seconds with the SPoT. So, (usage tip) if you haven't used the SPoT for more than a month, or you've moved it more than 500 - 600 miles since the last time you used it, send a "check-in" message. It might take it a couple of minutes to get a GPS lock for the check-in message but every start after that for the next several days (unless you move it more than 600 miles again) should take only a few seconds.
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Old 11-30-2007, 10:25 PM   #51
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Sweet!

I'm expecting one for X-mas!
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Old 12-01-2007, 03:22 AM   #52
AKDuc
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Quote:
Originally Posted by klebel
Well this blows it for me! I was hoping to pick one up for my trip from Seattle to Prudhoe Bay, AK next August. If it can't go any higher than N52 it is pretty much useless for me. I need it to go up to N70!
Hmm.. well, the way I read the coverage map you may or may not be able to send a signal once every 20 minutes in the lower half of Alaska only: http://www.findmespot.com/explorespot/coverage.aspx

SpotMaker, you can't even give us a month when there may be coverage up here for your far north American brethren?

Mark H.
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Old 12-01-2007, 07:02 AM   #53
SpotMaker
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Quote:
Originally Posted by AKDuc
Hmm.. well, the way I read the coverage map you may or may not be able to send a signal once every 20 minutes in the lower half of Alaska only: http://www.findmespot.com/explorespot/coverage.aspx

SpotMaker, you can't even give us a month when there may be coverage up here for your far north American brethren?

Mark H.
I honestly don't know.
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Old 12-02-2007, 05:54 AM   #54
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Saw a couple of good questions posted about this in another thread, so I'll ask them over here....

1) Antenna - is there anyway of mounting an external antenna onto this unit? I would rather keep this unit under my seat or in a pannier and then run an antenna to it. I don't fancy keeping this in my pocket then going for a tumble (more concerned about injuring myself rather than braking it).

2) The additional SAR insurance. Does this insurance only cover the registered owner of the SPOT or will it cover the user of the unit? As mentioned in the other thread - what happens if I'm with a friend who has a bad fall and I use the SPOT for assistance?
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Old 12-02-2007, 08:09 AM   #55
SpotMaker
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Quote:
Originally Posted by Essjay
Saw a couple of good questions posted about this in another thread, so I'll ask them over here....

1) Antenna - is there anyway of mounting an external antenna onto this unit? I would rather keep this unit under my seat or in a pannier and then run an antenna to it. I don't fancy keeping this in my pocket then going for a tumble (more concerned about injuring myself rather than braking it).

2) The additional SAR insurance. Does this insurance only cover the registered owner of the SPOT or will it cover the user of the unit? As mentioned in the other thread - what happens if I'm with a friend who has a bad fall and I use the SPOT for assistance?
1) Nope, no provision for an external antenna. The impedance match and line-loss requirements for the satellite transmitter are extremely critical. I dare say that most do-it-yourself wired antennas wouldn't work because of this.

It will work inside of just about any non-metallic enclosure though. On a bike it should track you just fine inside of a saddle bag. Our engineering director puts his in the luggage compartment of his Honda Gold Wing (fiberglass) and gets almost 100% throughput.

2) That's a great question! I don't know the answer though. Have you asked at the GEOS Alliance website? questions@geosalliance.com
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Old 12-02-2007, 09:14 AM   #56
offroute
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Quote:
Originally Posted by SpotMaker
The "check in" message actually transmits THREE TIMES. It transmits in the following pattern: As soon as the SPoT has a GPS fix it transmits, then 5 to 10 minutes later (randomly dithered) it transmits a second time, then 5 to 10 minutes after that (random again), it transmits a third time. These three transmissions all have the same internal packet ID which causes the SPoT back office to throw out the duplicates and only send one to the emails and cel-phones on your check-in list.

As a result, this coverage map:

http://www.findmespot.com/explorespot/coverage.aspx

Shows the probability of a check-in message getting through!
Hi Spotmaker,
I was unaware of the 3 transmissions for each check-in. Yesterday I took a two hour hike along the SF Yuba River near Nevada City, CA. Holding the unit out in front of my body I sent Check-Ins 6 times during the hike. Each time I waited until the Check-In light quit flashing, and then immediately pressed the Check-In button again to reactivate it and have it go through all three of its transmissions. Hike was along forested single track. Not one of my Check Ins made it through - even though it apparently sent 18 times. The only Check In that I got through was one sent after the hike from a bridge out in the middle of the canyon. So here's my concern-

It seems from my experience that the coverage map presents an optimistic view of actual performance. I understand that TRACK simply sends once every ten minutes, yet your previous post indicates that since Check Ins send three times, the likelyhood of having a successful Check In is quite high. I'm just not having that kind of success unless I provide a pretty darn clear view of the sky. This leads me to worry about how folks interpret the coverage map and their potential misuse in a critical situation.

For me this device is a must have. I sell these things. We sold out of our first shipment immediately and are seeing very high demand and interest. It does things no other product does. I just want to make sure that those I recommend it to understand that in a critical situation, every effort should be made to provide the clearest possible view of the sky. I wish the enclosed materials would stress this more.

Thanks much for engaging in a dialog here. I'm anxious to hear more of your tips and thoughts.

Offroute
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Old 12-02-2007, 02:44 PM   #57
TomW
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Quote:
Originally Posted by offroute
It seems from my experience that the coverage map presents an optimistic view of actual performance. I understand that TRACK simply sends once every ten minutes, yet your previous post indicates that since Check Ins send three times, the likelyhood of having a successful Check In is quite high. I'm just not having that kind of success unless I provide a pretty darn clear view of the sky. This leads me to worry about how folks interpret the coverage map and their potential misuse in a critical situation.
I'm sure the 99% success rate coverage area is under optimum conditions, i.e., a truly unobstructed view of the sky, and, since they don't have the Verizon dude out there conducting ground truth surveys every five feet, the coverage numbers are probably based on modelling (at least one satellite in view at least x degrees above the horizon, etc.). One could probably derive numbers based on their coverage map, modified by percent of obscured sky (e.g., say, 50% obscured = 66.6% success rate for three packets sent at 10 minute intervals). There may be some edge effects at high latitudes where the satellites never appear on the northern horizon (or southern horizon in the southern hemisphere) and where some satellites are out of range of any earth station. But I assume that's where Spot's coverage map goes to gray. Does that sound right?

This is fun. Good info.

Cheers.
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Old 12-03-2007, 06:46 AM   #58
SpotMaker
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Offroute,

You're experience with the check-in message is extremely puzzling to me.

Our offices in Covington LA sit in the middle of a piney woods. Our office property is surrounded by very tall pine trees.

In the middle of our office building back yard, we probably don't have any view of the sky lower than about 40 degrees. (In other words our view is roughly a cone from 90 degrees, straight up, to 40 degrees above the horizon. The horizon being 0 degrees.)

The last formal tally I saw, using a few dozen SPoTs in the back yard of our office, we received all but 6 check-in messages out of about 5,500 sent under the conditions I described above. (That's a 99.89% success rate.) To be clear, that's 5,500 complete bursts of three - the whole check in cycle being allowed to finish.

Globalstar's testing in open fields and/or over water has been better than 99.99 near the center of the orange areas, and around 99.0 at the edges of the dark orange areas.
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Old 12-03-2007, 07:41 AM   #59
offroute
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Quote:
Originally Posted by SpotMaker
Offroute,

You're experience with the check-in message is extremely puzzling to me.

Our offices in Covington LA sit in the middle of a piney woods. Our office property is surrounded by very tall pine trees.

In the middle of our office building back yard, we probably don't have any view of the sky lower than about 40 degrees. (In other words our view is roughly a cone from 90 degrees, straight up, to 40 degrees above the horizon. The horizon being 0 degrees.)

The last formal tally I saw, using a few dozen SPoTs in the back yard of our office, we received all but 6 check-in messages out of about 5,500 sent under the conditions I described above. (That's a 99.89% success rate.) To be clear, that's 5,500 complete bursts of three - the whole check in cycle being allowed to finish.

Globalstar's testing in open fields and/or over water has been better than 99.99 near the center of the orange areas, and around 99.0 at the edges of the dark orange areas.
I tested again yesterday on another hike. This time the canyon was a bit more open and I did not have overhanging tree canopy most of the time. My success rate was around 50% with Check Ins. The day before when I had no success I had the LEDs blinking out of sync a significant portion of the time indicating the GPS could not lock. Yesterday with 50% success the LEDs were in sync nearly all of the time.

I had similar experience with another demo unit prior to this. Am hoping other users will provide their experiences here. I always waited for the three attempts before reactivating - so I am sure I am using correctly...
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Old 12-03-2007, 08:26 AM   #60
SpotMaker
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Quote:
Originally Posted by offroute
I tested again yesterday on another hike. This time the canyon was a bit more open and I did not have overhanging tree canopy most of the time. My success rate was around 50% with Check Ins. The day before when I had no success I had the LEDs blinking out of sync a significant portion of the time indicating the GPS could not lock. Yesterday with 50% success the LEDs were in sync nearly all of the time.

I had similar experience with another demo unit prior to this. Am hoping other users will provide their experiences here. I always waited for the three attempts before reactivating - so I am sure I am using correctly...
Wow.

Perhaps if I were to see exactly what you are doing I'd have some ideas, but I am just floored by this result.

The figures I quoted above were from tests done by our lab guys.

I personally have sent several hundred check-in messages from several test SPoTs.

I've had exactly zero fail to go through if it were outdoors with even a 30 - 40 % view of the sky. In other words, the only check-in messages I've had fail were done indoors. The check in is supposed to be very nearly 100%.

I've sent check in messages:
  • With the SPoT cradled in my palm.
  • Clipped to my belt.
  • On a vehicle dashboard.
  • Under moderate tree cover ("filtered" view of the sky).
  • Sitting in my living room window.

And many others.

I'm going to have to do some more pondering of this. It is really strange.
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