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DeLorme PN-40...too accurate?


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While attending an event a week or two back, a friend (who had just purchased his own PN-40) commented that the unit is TOO accurate. Last night at an event I hosted, another friend, who took the plunge after seeing mine, stated his unit was very accurate!

 

When asked why the first thought the unit was too accurate, he mentioned that he could tell what kind of unit was used for hiding (I wasn't clear as to why because of the confusion of the event and all), he stated he loved his PN over the 60CSx his wife was using when caching with him! The friend I talked to last night commented that the PN didn't make him walk in circles like his 60CSx had. This friend was pretty new to the PN and I had to let him in on the Cache Register app, he was loading each cache one at a time. I wonder if he knows about the field notes..... *(mental note to email friend)*

 

Anyone else love the accuracy of their GPS?

 

edit for typo...D'OH

Edited by Rockin Roddy
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When I replaced my Garmin Etrex (yellow) with a Magellan 500LE, I thought the Maggie was the cat's meow...locked on and stayed locked on. Of course, there was a logical reason, the SirfIII chip my Maggie had was much better than the old tech in the etrex. Now, after buying the PN-40, I see a vast improvement from the Maggie, I don't do much circling now myself!

 

But, some say the SirfIII is a better chip than the PN-40's?

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SirfIII is considered the gold standard for it's high level of accuracy.

 

I do like the fact the accelerometer in the PN works to keep you from a position wander (most of the time) and the PN does seem to be more direct, but I did experience some old Maggie style boomerang a couple weeks back and I'm still analyzing the data from the track. I suspect I had a 2-D fix or a less than desirable 3-D fix.

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SirfIII is considered the gold standard for it's high level of accuracy.
Sensitive and accurate, but it has other problems. My old Lowrance iFinder H2O (SirfIII based) had a "track smoothing" switch that turned on/off a feature of the chipset called static navigation. Set one way, it did a lousy job of tracking at low speed. Set the other, low speed tracking was better -- but when you weren't moving the position would wander and the compass would spin. At least that's how I remember it from a few years ago -- I might have the details wrong.
...the accelerometer in the PN works to keep you from a position wander ...
Are they really doing this now? Last time I recall reading about it (a few months ago), Chip Noble said something along the lines of "good idea, thinking about that" -- I got the impression accelerometer-based track smoothing was in the future. I haven't seen anything in the firmware update notes. Be neat if they did though.
I did experience some old Maggie style boomerang a couple weeks back and I'm still analyzing the data from the track. I suspect I had a 2-D fix or a less than desirable 3-D fix.
You mean this one http://forums.Groundspeak.com/GC/index.php...t&p=3974409 mentioned back on 22 June? I've been curious to see those tracks.

 

But I wander... next post will address the OP's question.

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Roddy, I love the accuracy of the PN-40. But to answer the title of your post -- no GPS can be "too accurate."

 

I always laugh when someone says their GPS (be it DeLorme, Garmin, or Brand X) is so accurate that it makes Geocaching too easy, or that it leads them to "ground zero" every time -- and fans of the brand under discussion take that as proof of how good it is.

 

The best any GPS can do is take you to the posted coordinates. And unless the hider used a very good GPS and took great care to get a perfect waypoint, those coordinates can/will be off by some number of feet or maybe yards. So... if your GPS takes you to the exact right spot, all that means is it's as good as (not necessarily any better) than what the hider was using. More often than not, the best any GPS can do is get you "close enough" -- and then it's up to you.

 

You're a serious cacher with lots of finds -- but if you're finding it too easy I think you should take credit for your years of practice and superior Geo-Sense. Many a cacher CAN be standing right on the spot and not see it :D

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Roddy, I love the accuracy of the PN-40. But to answer the title of your post -- no GPS can be "too accurate."

 

I always laugh when someone says their GPS (be it DeLorme, Garmin, or Brand X) is so accurate that it makes Geocaching too easy, or that it leads them to "ground zero" every time -- and fans of the brand under discussion take that as proof of how good it is.

 

The best any GPS can do is take you to the posted coordinates. And unless the hider used a very good GPS and took great care to get a perfect waypoint, those coordinates can/will be off by some number of feet or maybe yards. So... if your GPS takes you to the exact right spot, all that means is it's as good as (not necessarily any better) than what the hider was using. More often than not, the best any GPS can do is get you "close enough" -- and then it's up to you.

 

You're a serious cacher with lots of finds -- but if you're finding it too easy I think you should take credit for your years of practice and superior Geo-Sense. Many a cacher CAN be standing right on the spot and not see it :laughing:

 

You and I both know this, Lee, I am just passing on what I have been told by a few new owners! As to the getting to the right spot comment, well, the PN does seem to lead me in the right direction most of the time (there have been a few instances of course), which is a huge improvement to both the units I have put to pasture (actually, I gifted them to newbs....poor cachers, I hope they don't hate me for that lol).

 

I did get a chuckle when I was told it was too accurate, but I kinda understood what was being said! :anitongue: But, I will stand behind the PN being very accurate, I have put it through the tests with my back-up Maggie. The Maggie just isn't as good as far as I've experienced! Not to say the Maggie isn't a good unit, I loved it right up until I bought the PN! :D

 

ETA: the units I gifted were the etrex yellow (x2) and an etrex blue, the Maggie is my back-up as stated. Also, I credit much of our success in finding to the extra eyes whcih almost always accompanies me (my son KAboom...and of course Tod who used to be a bit of help as well, but not as much as one would think lol)

Edited by Rockin Roddy
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SirfIII is considered the gold standard for it's high level of accuracy.
Sensitive and accurate, but it has other problems. My old Lowrance iFinder H2O (SirfIII based) had a "track smoothing" switch that turned on/off a feature of the chipset called static navigation. Set one way, it did a lousy job of tracking at low speed. Set the other, low speed tracking was better -- but when you weren't moving the position would wander and the compass would spin. At least that's how I remember it from a few years ago -- I might have the details wrong.
...the accelerometer in the PN works to keep you from a position wander ...
Are they really doing this now? Last time I recall reading about it (a few months ago), Chip Noble said something along the lines of "good idea, thinking about that" -- I got the impression accelerometer-based track smoothing was in the future. I haven't seen anything in the firmware update notes. Be neat if they did though.
I did experience some old Maggie style boomerang a couple weeks back and I'm still analyzing the data from the track. I suspect I had a 2-D fix or a less than desirable 3-D fix.
You mean this one http://forums.Groundspeak.com/GC/index.php...t&p=3974409 mentioned back on 22 June? I've been curious to see those tracks.

 

But I wander... next post will address the OP's question.

I thought I had read where the accelerometer was in play on one of the firmware updates. It seems to work excaptionally well once the compass has been calibrated. I may be wrong but that's my observation. I did notice it was very stable a couple of hikes ago versus the last hike. But yes, The mention of the hike I did on 6/21 is the one I'm currently analyzing and writing my report on. I had to collect my thoughts, then get the maps to line up, now to benchmark the specific areas with the track data.

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When I replaced my Garmin Etrex (yellow) with a Magellan 500LE, I thought the Maggie was the cat's meow...locked on and stayed locked on. Of course, there was a logical reason, the SirfIII chip my Maggie had was much better

 

It's a bit OT, but in the name of keeping GPS folklore accurate...

 

Explorist didn't use Sirf III. Magellan's Triton and many of their RoadMates do. Explorist's receiver was a 14 channel version of the 12 channel in-house design that was used in SporTrak/Meridian/Map 330. (If it were multiple choice, I'd recall Magellan's codename for those parts.) Those designs pretty much ruled the roost of reception until the Sirf III unitd came along a few years later.

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A friend at work just bought a PN-40. The first time I messed with it was inside a large building at work. Note that this building has a metal roof, cinder block walls and fairly small openings to the outside. Happened to page through the sat-signal page and it had several blue bars and was saying 5' accuracy.

 

The next day I let it warm up outside until it said it had 10' accuracy and averaged a waypoint in the parking lot. This was a gate post. We set a hike route to that WP I set and the thing zeroed out only 2' from where I averaged the WP. So far I'm impressed.

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When I replaced my Garmin Etrex (yellow) with a Magellan 500LE, I thought the Maggie was the cat's meow...locked on and stayed locked on. Of course, there was a logical reason, the SirfIII chip my Maggie had was much better

 

It's a bit OT, but in the name of keeping GPS folklore accurate...

 

Explorist didn't use Sirf III. Magellan's Triton and many of their RoadMates do. Explorist's receiver was a 14 channel version of the 12 channel in-house design that was used in SporTrak/Meridian/Map 330. (If it were multiple choice, I'd recall Magellan's codename for those parts.) Those designs pretty much ruled the roost of reception until the Sirf III unitd came along a few years later.

 

I could be wrong Robert, but I'm sure I saw the SirfIII logo on the box of my Maggie...I know I had read about it somewhere before the forums. Like I said, I could be wrong. I believe it was a 14 channel though...

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A friend at work just bought a PN-40. The first time I messed with it was inside a large building at work. Note that this building has a metal roof, cinder block walls and fairly small openings to the outside. Happened to page through the sat-signal page and it had several blue bars and was saying 5' accuracy.

 

The next day I let it warm up outside until it said it had 10' accuracy and averaged a waypoint in the parking lot. This was a gate post. We set a hike route to that WP I set and the thing zeroed out only 2' from where I averaged the WP. So far I'm impressed.

Was the unit on prior to going inside the facility? I'll warrant even though you had the blue bars, you probably did not have signal from WAAS. The WAAS ephemeris will linger for about 10 minutes after loss of signal.

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A friend at work just bought a PN-40. The first time I messed with it was inside a large building at work. Note that this building has a metal roof, cinder block walls and fairly small openings to the outside. Happened to page through the sat-signal page and it had several blue bars and was saying 5' accuracy.

 

The next day I let it warm up outside until it said it had 10' accuracy and averaged a waypoint in the parking lot. This was a gate post. We set a hike route to that WP I set and the thing zeroed out only 2' from where I averaged the WP. So far I'm impressed.

Was the unit on prior to going inside the facility? I'll warrant even though you had the blue bars, you probably did not have signal from WAAS. The WAAS ephemeris will linger for about 10 minutes after loss of signal.

 

No, it was not on prior. He had loaded T8 on his laptop and I was showing him how to use T8 (transfer WP's, cut maps, etc.). We had turned on the PN to do the data transfers. I think it had been on for about 15 minutes when he scrolled to the sat page and noticed the 5" accuracy and blue bars. I couldn't believe it.

 

In the past I had walked in to that same building with my -20. It immediately lost 3D lock but did keep a couple of sat bars.

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Explorist didn't use Sirf III. Magellan's Triton and many of their RoadMates do. Explorist's receiver was a 14 channel version of the 12 channel in-house design that was used in SporTrak/Meridian/Map 330.

 

I could be wrong Robert, but I'm sure I saw the SirfIII logo on the box of my Maggie...I know I had read about it somewhere before the forums. Like I said, I could be wrong. I believe it was a 14 channel though...

I'll back Robert up on this one, Roddy (I've yet to catch him being wrong...one of the more infuriating things about him :unsure: ). I had an Explorist 500, and I recall suffering from a little SiRF envy when those chips came on market. I'll defer to his recollection of what was actually in the Explorist, as that is beyond my memory capability.

 

One of the things that helped make the Explorists display such stable position lock was that they leaned pretty heavily on computing a moving average. That had advantages in some situations, but was a cause of the overshoot many of us saw in zeroing in on a cache.

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Explorist didn't use Sirf III. Magellan's Triton and many of their RoadMates do. Explorist's receiver was a 14 channel version of the 12 channel in-house design that was used in SporTrak/Meridian/Map 330.

 

I could be wrong Robert, but I'm sure I saw the SirfIII logo on the box of my Maggie...I know I had read about it somewhere before the forums. Like I said, I could be wrong. I believe it was a 14 channel though...

I'll back Robert up on this one, Roddy (I've yet to catch him being wrong...one of the more infuriating things about him :drama: ). I had an Explorist 500, and I recall suffering from a little SiRF envy when those chips came on market. I'll defer to his recollection of what was actually in the Explorist, as that is beyond my memory capability.

To put this to rest here's a link to a 2006 topic mentioning the chipset in the eXplorist. It's Magellan's Baldur. The Thales Navigation links in my post don't work anymore, but Google turns up a few references to the Baldur chipset and the eXplorist.

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But, some say the SirfIII is a better chip than the PN-40's?

My experience so far is that, if setup properly (some of the cheaper pucks can be a little wonky in their initial setup, the Garmin configuration chosen in their receivers is excellent based on accounts I have heard) the SiRF III blows away the STM Cartesio, especially if you live at moderate northern or southern latitudes (like New York State) which have the WAAS sats lower to the horizon.

 

The SiRF III's WAAS support (if turned on - my Holux puck had it off by default!) simply blows away the Cartesio - Firmware fixes have taken the Cartesio a long way but nowhere close to the SiRF III.

 

The top dog in performance, accuracy, and sensitivity (see various side-by-side tests of GPS dataloggers over at gpspassion.com) seems to be the MTK v2 chipset. It's an incredible chipset, but so far only available in external "pucks" and loggers. Garmin and MTK recently released a joint press release that they will be including the MTK2 in future Garmin receivers. (Maybe the new Dakotas might have it? I haven't seen any info yet as to what the Dakotas will include chipset-wise.)

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But, some say the SirfIII is a better chip than the PN-40's?

My experience so far is that, if setup properly (some of the cheaper pucks can be a little wonky in their initial setup, the Garmin configuration chosen in their receivers is excellent based on accounts I have heard) the SiRF III blows away the STM Cartesio, especially if you live at moderate northern or southern latitudes (like New York State) which have the WAAS sats lower to the horizon.

 

The SiRF III's WAAS support (if turned on - my Holux puck had it off by default!) simply blows away the Cartesio - Firmware fixes have taken the Cartesio a long way but nowhere close to the SiRF III.

 

The top dog in performance, accuracy, and sensitivity (see various side-by-side tests of GPS dataloggers over at gpspassion.com) seems to be the MTK v2 chipset. It's an incredible chipset, but so far only available in external "pucks" and loggers. Garmin and MTK recently released a joint press release that they will be including the MTK2 in future Garmin receivers. (Maybe the new Dakotas might have it? I haven't seen any info yet as to what the Dakotas will include chipset-wise.)

 

Was there a point in there somewhere that I missed?

 

Back to the question, do you enjoy the same accuracy I and many others are seeing? After reading the latest Garmin thread comments, I would guess some aren't! Seems some are pretty ticked, I saw where one was tempted to play catch with a tree with their unit? :drama:

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Was there a point in there somewhere that I missed?
Well, you did bring up the SiRF and mention comparison between chipsets. But I can sympathize here:( it must be SO irritating for someone to misread your comment, and go off in a different direction ...

 

Entropy, aren't you ashamed of yourself ? :drama:

Edited by lee_rimar
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Was there a point in there somewhere that I missed?
Well, you did bring up the SiRF and mention comparison between chipsets. But I can sympathize here:( it must be SO irritating for someone to misread your comment, and go off in a different direction ...

 

Entropy, aren't you ashamed of yourself ? ;)

 

About as ashamed as you should be for your off-topic posting? Yes, the chipsets were brought up, but not to compare them as you may seem to think. More as an ON-TOPIC example of how it started and how we've seen the progression of tech. I hardly think anywhere was made mention of which was best and I certainly wonder what the talk of "pucks" has to do with the topic.... Even Robert acknowleges it was off-topic when he posted a correction to my thought of the chipset in my Maggie.

 

Glad you were around to help though, Lee, wouldn't be the same if you weren't giving us your in-depth analyses :drama:

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I bought the Delorme PN-40 today, and my mom decided to buy one for herself. With tax and everything they came out to $440 each, and I'd like to say they are worth every penny. I took about 2 hours to mess around with the Garmin Colorado, Oregon, and 60cxs, as well as some lowence, and magallin models. The colorado was slightly better, but it costs almost double for a functioning unit. The salesman said "they are nearly identical in proformance" and had actually taken them out for a test trial. Delorme maps were free, and it only took me about 20 minutes from the time I opened the box before I was plugging in Caches from the site and not long after that I found a geocache my Garmin kept losing signal around. Thanks for the good advice everyone, I am glad I read up on it.

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how can a GPS be TOO accurate? isn't that the point of them, to get you to the exact coordinates.

 

if you are looking for a challenge, don't worry. caches are placed by people with hiend and lowend gps's, so even if yours is super dooper accurate, the person placing it may have a unit that is out 15' or more and might not have averaged the hide.

 

i wouldn't be stressing too much about my GPS being too accurate.

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how can a GPS be TOO accurate? isn't that the point of them, to get you to the exact coordinates.

 

if you are looking for a challenge, don't worry. caches are placed by people with hiend and lowend gps's, so even if yours is super dooper accurate, the person placing it may have a unit that is out 15' or more and might not have averaged the hide.

 

i wouldn't be stressing too much about my GPS being too accurate.

 

Probably only read the title of the post? :P

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Probably only read the title of the post? <_<

 

and the first line of his post :)

 

anyway, i don't know how or why anyone would consider a GPS too accurate. if that's not the point of this thread, then the title should be changed.

 

OR, you could read the thread instead of making assumptions and then complaining about not knowing what you're commenting on. It's a lot like caching, read the cache page and you'll have a better idea of what it is you're going after....

 

Take a shot, I bet you can do it....read the entire OP and maybe even venture a bit further into the thread. You might even understand what is being discussed. :yikes:

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Take a shot, I bet you can do it....read the entire OP and maybe even venture a bit further into the thread. You might even understand what is being discussed. <_<

 

settle down Rockin Roddy'. :)

 

i'll read the post next time before commenting on a title.

 

my appolgies :yikes:

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Take a shot, I bet you can do it....read the entire OP and maybe even venture a bit further into the thread. You might even understand what is being discussed. :yikes:

 

settle down Rockin Roddy'. <_<

 

i'll read the post next time before commenting on a title.

 

my appolgies :lol:

 

It's all good! :)

 

So, are you thrilled with the accuracy of your favorite unit?

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It's all good! :)

 

So, are you thrilled with the accuracy of your favorite unit?

 

thanks,

 

i've only been using it a couple months, but i love my Legend HCx, i was going to get a Lowrance Out&Back, but they kept delaying it and i couldn't wait any longer.

 

just placed our 1st cache with it, and a comment of "Perfect coordinates!" was good enough to confirm my thoughts that it is a good unit.

Edited by brucered
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If this thread makes anyone to have the urge to sell there PN-40 and get something else, Let me know. I'll be in the market for a PN-40 in the next week or so. :unsure:

Are you aware that there are a limited number of the PN-40SE models made available again?

http://shop.delorme.com/OA_HTML/DELibeCCtd...p;section=10461

 

They are available only through DeLorme and I think that there is a $125 discount to the price shown in the link.

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I wasn't happy with a pn-20, it would lose lock where my etrex h kept signal, it also chewed up the batteries in the process. I am happy with the etrex h accuracy. I am not saying it is the best,but it does get me close, and with some experience you can do pretty good, plus battery life is good.

 

Are all garmin "h" models the same accuracy. So for greater accuracy i would have to go up to a garmin 60csx model?

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I'd like better accuracy, although I'm not displeased with my Venture Cx. I use mission planning software so I know what time of day to expect the best satellite configuration and make the best of what I've got.

 

I often use a 60CSx at work, but they're a little big and bulky for my taste. I tried a friends Oregon for a couple days and it was accurate when tested at a point with known coordinates (a survey marker in the open), but I never got the chance to go geocaching with it. As others have said, that only tells you if the cache owner posts good coordinates.

 

I plan on buying my own Oregon this weekend and I intend to test it thoroughly using the new averaging feature. Unfortunately, any navigation-grade gps I've used rounds its coordinates off too much to really know how close you are getting.

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But, some say the SirfIII is a better chip than the PN-40's?

 

The SiRF III's WAAS support (if turned on - my Holux puck had it off by default!) simply blows away the Cartesio - Firmware fixes have taken the Cartesio a long way but nowhere close to the SiRF III.

 

 

Exaggerate much? :rolleyes:

 

I disagree. I've owned GPSrs using both chipsets and the difference is negligible. I think people just like to bring this topic up to stir the pot.

 

With the latest firmware to date, both chipsets work equally as well. (judging from both the PN-40 and 60CSX). Due to the fact cartesio is newer to the GPS market, the older firmware did have some bugs, however those have been ironed out.

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I wasn't happy with a pn-20, it would lose lock where my etrex h kept signal, it also chewed up the batteries in the process. I am happy with the etrex h accuracy.

Don't judge the 30 & 40 based upon the 20's performance here. Completely different electronics inside. Though the 30 & 40 do still have relatively short battery life compared to an eTrex or some other models.
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I disagree. I've owned GPSrs using both chipsets and the difference is negligible. I think people just like to bring this topic up to stir the pot.

 

With the latest firmware to date, both chipsets work equally as well. (judging from both the PN-40 and 60CSX). Due to the fact cartesio is newer to the GPS market, the older firmware did have some bugs, however those have been ironed out.

I think there's still room for differing opinions with regard to WAAS, the PN-40, and other units (without specific regard to chipset). I've lived through all the PN-40 public betas, 2.5 RTM and 2.6 RTM firmware on the PN-40. There is no doubt that WAAS reception and the use of WAAS corrections has improved markedly on the PN-40. However, my PN-40 still underperforms relative to my Colorado. In my area (St. Louis), the Colorado has WAAS information and applies corrections virtually all the time. The PN-40 does so significantly less frequently (even when I go out of my way to compensate for the directional nature of the PN-40 patch antenna).

 

This may well be due to geography, but -- at least for some of us -- there's a still a difference.

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Exaggerate much? :laughing:

 

I disagree. I've owned GPSrs using both chipsets and the difference is negligible. I think people just like to bring this topic up to stir the pot.

 

With the latest firmware to date, both chipsets work equally as well. (judging from both the PN-40 and 60CSX). Due to the fact cartesio is newer to the GPS market, the older firmware did have some bugs, however those have been ironed out.

 

Amen.

 

I also agree with twolpert.. and substitute the OR for the PN-40 in his post. Clearly WAAS improvements but still not as WAAS-reliable as the older units.

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Exaggerate much? :laughing:

 

I disagree. I've owned GPSrs using both chipsets and the difference is negligible. I think people just like to bring this topic up to stir the pot.

 

With the latest firmware to date, both chipsets work equally as well. (judging from both the PN-40 and 60CSX). Due to the fact cartesio is newer to the GPS market, the older firmware did have some bugs, however those have been ironed out.

 

Amen.

 

I also agree with twolpert.. and substitute the OR for the PN-40 in his post. Clearly WAAS improvements but still not as WAAS-reliable as the older units.

 

I have used my OR 300 for what...a week now (maybe a bit longer)? I have not seen a WAAS lock yet on it. However, I received a brand new PN-40 today and guess what, WAAS lock 15 minutes into allowing it to acquire sats for the first time! Have +/- 6' right now! Gotta love that! Both units have the latest updates.

 

Guess which unit I plan to keep! ;) For the time being (about one night lol) I plan to test both units side-by-side! Right now, both are on and sats acquired, both istting on my desk....the PN-40 has the aforementioned +/- 6' while the OR is jumping from 65' to 43'....40'....52'.....61'.....43'

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Exaggerate much? :laughing:

 

I disagree. I've owned GPSrs using both chipsets and the difference is negligible. I think people just like to bring this topic up to stir the pot.

 

With the latest firmware to date, both chipsets work equally as well. (judging from both the PN-40 and 60CSX). Due to the fact cartesio is newer to the GPS market, the older firmware did have some bugs, however those have been ironed out.

 

Amen.

 

I also agree with twolpert.. and substitute the OR for the PN-40 in his post. Clearly WAAS improvements but still not as WAAS-reliable as the older units.

 

I have used my OR 300 for what...a week now (maybe a bit longer)? I have not seen a WAAS lock yet on it. However, I received a brand new PN-40 today and guess what, WAAS lock 15 minutes into allowing it to acquire sats for the first time! Have +/- 6' right now! Gotta love that! Both units have the latest updates.

 

Guess which unit I plan to keep! ;) For the time being (about one night lol) I plan to test both units side-by-side! Right now, both are on and sats acquired, both istting on my desk....the PN-40 has the aforementioned +/- 6' while the OR is jumping from 65' to 43'....40'....52'.....61'.....43'

I just got my new Dakota and sitting on my desk, the PN-40 is at 10ft and the Dakota is at 59ft. I will be using both for caching this weekend and see if the Dakota is worth keeping.

Edited by The Yinnie's
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Loading new maps to the PN-40 (MI, OH, IL and IN) but was tired of watching the OR jump around, never gettig below 31'...so I took it outside where it has been for about 10 minutes now. The +/- has improved significantly to 13'...still not as good as the PN-40's last reading which was taken while sitting on my desk?

 

As soon as I get the maps loaded, I will take them both for a tour...

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Loading new maps to the PN-40 (MI, OH, IL and IN) but was tired of watching the OR jump around, never gettig below 31'...so I took it outside where it has been for about 10 minutes now. The +/- has improved significantly to 13'...still not as good as the PN-40's last reading which was taken while sitting on my desk?

 

As soon as I get the maps loaded, I will take them both for a tour...

As you suggest, you really need to try the units in the field. Comparing EPE numbers across different models, let alone across manufacturers, is not meaningful. None of the manufacturers disclose their EPE formulas. All of them are probabilities, and even the choice of probability confidence level makes a significant difference in the reported EPE. For example, CEP (one of the more widely cited formulas) offers a 50% probability that your reported position is within EPE feet of your actual position. To raise that probability to 95%, you would have to approximately double the EPE.

 

This is why EPE on a single unit should be treated as a relative figure of merit ("smaller is better"), rather than a guarantee of accuracy. And why comparisons across different manufacturers/models is meaningless. What counts is repeatability on the ground.

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Loading new maps to the PN-40 (MI, OH, IL and IN) but was tired of watching the OR jump around, never gettig below 31'...so I took it outside where it has been for about 10 minutes now. The +/- has improved significantly to 13'...still not as good as the PN-40's last reading which was taken while sitting on my desk?

 

As soon as I get the maps loaded, I will take them both for a tour...

As you suggest, you really need to try the units in the field. Comparing EPE numbers across different models, let alone across manufacturers, is not meaningful. None of the manufacturers disclose their EPE formulas. All of them are probabilities, and even the choice of probability confidence level makes a significant difference in the reported EPE. For example, CEP (one of the more widely cited formulas) offers a 50% probability that your reported position is within EPE feet of your actual position. To raise that probability to 95%, you would have to approximately double the EPE.

 

This is why EPE on a single unit should be treated as a relative figure of merit ("smaller is better"), rather than a guarantee of accuracy. And why comparisons across different manufacturers/models is meaningless. What counts is repeatability on the ground.

 

Understood. However, I don't hold a lot of hope that my OR is near as accurate as my PN-40 is (although not truly sure yet since I just received the PN-40...going off previous experience). From all indications thus far, the OR seems to be very unstable and might even have some tech problems with it! This isn't indicative of ALL the OR, just the one I am using at this time, which will be going back...I might just have to grab another to see how it works. Not sure yet on that though...

 

I will say, after I took the OR back outside (I allowed both units to acquire sat lock while on my deck), it did come down a good amount, to around 13' I think was the best reading I had on it! I just now turned my PN-40 on while sitting here and it acquired sat lock within a minute and is now reading +/- 11' while sitting on my desk.

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If this thread makes anyone to have the urge to sell there PN-40 and get something else, Let me know. I'll be in the market for a PN-40 in the next week or so. :mad:

Are you aware that there are a limited number of the PN-40SE models made available again?

http://shop.delorme.com/OA_HTML/DELibeCCtd...p;section=10461

 

They are available only through DeLorme and I think that there is a $125 discount to the price shown in the link.

 

Thanks so much. This has really helped making a decision.

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