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fizzymagic

Week Number overflow

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I thought about posting this in the GPS forum, but I think it is of more general interest.  Today I had a problem with my field notes.  They all had a date of March 11, 1999.  Turns out this is a case of my particular GPS model (Delorme PN-60) experiencing the week number overflow a little early. For the next 1024 weeks, my GPS will give the wrong date.  The base date they apparently used in the firmware is in March of 1999.

 

Here's a quick description of the issue:  the GPS satellites send the current date to you GPS using a week number since Jan 6 1980.  They only allocated 10 bits for it, though, so 1024 weeks from then (in August 1999) it overflowed for the first time. The next overflow is due in April 2019, when everyone's GPS will start showing the wrong date unless the GPS manufacturer put in some way to accommodate the overflow.  Mine just overflowed about 6 months early for no particularly good reason.  But it will happen to everyone, especially those with older GPS units.

 

Is anyone else with a Delorme seeing the same thing?  It's easy enough to fix (I wrote myself a little Python script to add 7168 days = 7 * 1024 weeks to the date for each field note) but it is annoying in a minor way.  Maybe we can convince Garmin to fix it!

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Hmm... Interesting.  It's like Y2K all over again.

I wonder if anyone can find out specific models that would be affected (or, possibly easier, which models AREN'T affected).  (For example, we have a vested interest in Oregon 650t's working properly.)

 

It sounds like the dates will just cycle through the same 19+ year range unless they update the base date in the firmware (or made some other accommodation, as you pointed out).

(It's too early for me to write a program to model this, but it sounds as if, with only 10 bits, you're limited to 1023 weeks from whatever the base week is and this will constantly reset to 0 whenever it rolls over into the 11th bit.)

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Thanks for the explanation. I had been wondering what was up with my Delorme's date since I knew it received the date from the satellites - I just didn't realize how it was being sent and interpreted.

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I have the same issue on my PN-60w.  I noticed it when I downloaded my recent tracks which are defined by date they are all the same date such as 1999-03-10, XXXXXX.gpx.  With Field Notes I use a text editor to correct the dates prior to downloading because Geocache will not recognize old dated Notes.

 

I went to Garmin's "Migrating from old Delorme Forum" looking for an answer but none posted.

 

Of more concern to me is how will the affect my inReach messages.  I have the older model transceiver paired to my PN.  Sent a message to myself and it wasn't received.  Garmin.inreach could not help with legacy inReach and recommended sending a email to support@delorme.com which I did.  Now I wait.

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10 hours ago, fizzymagic said:

I thought about posting this in the GPS forum, but I think it is of more general interest.  Today I had a problem with my field notes.  They all had a date of March 11, 1999.  Turns out this is a case of my particular GPS model (Delorme PN-60) experiencing the week number overflow a little early. For the next 1024 weeks, my GPS will give the wrong date.  The base date they apparently used in the firmware is in March of 1999.

 

Here's a quick description of the issue:  the GPS satellites send the current date to you GPS using a week number since Jan 6 1980.  They only allocated 10 bits for it, though, so 1024 weeks from then (in August 1999) it overflowed for the first time. The next overflow is due in April 2019, when everyone's GPS will start showing the wrong date unless the GPS manufacturer put in some way to accommodate the overflow.  Mine just overflowed about 6 months early for no particularly good reason.  But it will happen to everyone, especially those with older GPS units.

 

Is anyone else with a Delorme seeing the same thing?  It's easy enough to fix (I wrote myself a little Python script to add 7168 days = 7 * 1024 weeks to the date for each field note) but it is annoying in a minor way.  Maybe we can convince Garmin to fix it!

 

I envisioned someone of your geocaching stature using a top of the line Garmin. Thanks for ruining that image ;-)

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4 hours ago, bflentje said:

 

I envisioned someone of your geocaching stature using a top of the line Garmin. Thanks for ruining that image ;-)

 

Garmin units are overpriced by about a factor of 2 and I don't like the UI.  But I may end up with one in the next year....

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I contacted support@Delorme.com about the 1999 problem and here is their reply.

 

Hello Robert
Thank you for contacting Garmin Product Support and I apologize for the issue experienced with your DeLorme PN-Series GPS device.
Due to how the device uses Global Positioning Satellites to set its own time and how technology changes rapidly over the years, the PN-Series GPS will unfortunately no longer display the current correct time.  We sincerely apologize for this inconvenience.
At this point; due to the number of improvements and the plethora of additional features and functions, we would recommend upgrading to a newer Garmin Handheld GPS.  Please review the links below for some models comparable to your older DeLorme PN-Series GPS.

InReach Explorer + – Maps with premium satellite communications.
https://buy.garmin.com/en-US/US/p/561269/pn/010-01735-10#
 

GPSMap 66S – Premium rugged (MIL-STD-810G) handheld GPS. 
https://buy.garmin.com/en-US/US/p/598408/pn/010-01918-10#overview
 

Instinct (It’s MORE than just a watch!…and as a wearable…it can always be on you…surf, hike, train and work…it’s the ultimate tool for its price point)
https://buy.garmin.com/en-US/US/p/621802

Again, I apologize for the issue with your PN-Series GPS and hope with the overabundance of high-end rugged GPS devices Garmin  provides, something will fulfill your navigation needs.
Your older inReach does not need to Sync.  Those older devices only did a Sync to update firmware and you have the latest for that older device.
Please let us know if you have additional questions or concerns. 
Regards,
Kurt Ringrose
Product Support, Garmin Outdoor (inReach)
Garmin International
http://support.garmin.com


The GPSMap 66S will be available in 5-8 weeks and costs $449.99.  The inReach Explorer + costs $449.99.

It will cost me $900.00 + shipping to duplicate what I have now.

 



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48 minutes ago, Capt. Bob said:

I contacted support@Delorme.com about the 1999 problem and here is their reply.

Shoot. I was so hoping the answer would be, "We're not going to do anything about it, but here's the code for the firmware. Have at!" There are so many reasons I keep hoping they'll let the code loose, and I thought this might make the difference. I don't suppose anyone has stolen the source code and wants to slip me a copy? I'll make it worth your while if I can produce a fix.

 

When I noticed the date go bad on my PN-60w, I figured it was some kind of roll over fail. I don't use field notes, so fixing them up wouldn't do me any good, but the bad date still causes me two problems. First, obviously, is that the GPSr no longer tells me what date I should put in the logs I'm signing. It's really annoying to have to pull out my cell phone at every cache. The second problem -- where I actually saw the bug first -- is that it means the dates on PQ files are wrong. I usually note how old a PQ is when I replace it with a newer one just to see how fresh I'm keeping different areas, so I was quite startled when windows asked me whether I really wanted to copy the new PQ or would I rather keep the old one from March, 1999.

 

For some reason I didn't notice this conversation until now. I'll check my PN-40 when I get home just to confirm, but since it uses the same firmware, I assume it has the same problem.

 

After geocaching with a cracked screen for a few years now, I always assumed that physical failure would be my PN-60's ultimate demise, so it's both amusing and sad that what's really going to force me to switch to one of those less desirable units is a software bug.

Edited by dprovan
was "big", should have been "bug".

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4 hours ago, Capt. Bob said:

The GPSMap 66S will be available in 5-8 weeks and costs $449.99.  The inReach Explorer + costs $449.99.

It will cost me $900.00 + shipping to duplicate what I have now.

 

Bummer about the cost. If you're primarily planning to use the inReach as a satellite messenger (not for navigation), you might see if the inReach Mini would work for you. It's slightly less expensive.

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I am beginning to see other problems with the PN-60w that seem to be getting worse.  It now takes a long time to acquire satellites which implies the almanac data isn't being read properly.  Also the ephemeris data must be affected because once satellites have been acquired the EPE varies wildly over time.

(solved the problem with a NVM reboot)

 
It's a shame that Garmin/Delorme won't undertake revising the firmware to correct the date issue.  It's irresponsible of them to not notify users of the problem particularly those users, like me, who are paired to inReach.  It could be a life threatening situation.  I suppose somewhere in their multi-paged legal agreement they are absolved of any liabilities so they don't care.

Edited by Capt. Bob
Update results

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While I am unhappy that Garmin won't even let us fix our own firmware, concerns about ephemeris and almanac data should not be issues.  My PN-60 is still acquiring the satellites just fine and the accuracy also seems fine.

 

I kind of don't want to reward Garmin for their bad customer service by buying a handheld from them.

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11 hours ago, fizzymagic said:

I kind of don't want to reward Garmin for their bad customer service by buying a handheld from them.

Let me know what alternative you find...

 

But to be fair, while Garmin obviously wanted to get the old PN GPSrs out of the picture as quickly as possible, DeLorme had given up on the PN's long before that. It's not as if they were still supporting the firmware even before Garmin bought them. They could have published the code, just as well.

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It's not just DeLorme items that are affected. I have a Garmin Etrex Venture HC, and this started to show an incorrect date a couple of weeks ago. I phoned Garmin, they told me I wasn't the first to report this trouble recently, and they were working on a solution.

 

The issue is clearly related to the week number in the GPS data. 21st October 2018 was exactly 7000 days (1000 weeks) after the last week number rollover on 21st/22nd August 1999. Thus it looks like the unit software cannot handle GPS data week numbers larger than 3 decimal digits.

 

Given this problem, I suppose there is little chance of the device dealing gracefully with the week number rollover coming on 6th/7th April 2019. I remember back in August 1999 I had a Garmin 'handheld' GPS, and to cope with the rollover it required a hard hard reset, then a considerable period to gather data until it was working again. Anxious moments...  

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I'd like to find a replacement for my PN-60W and inReach but don't know if there is anything comparable.  Upset the PN-60W was discontinued but I guess I can't blame DeLorme. Perhaps they weren't selling enough units to keep market share and that is why they got bought out?  In the meantime I wrote a simple formula in excel and convert before I post. Just add 7168 to the date displayed and you'll have your post date.  You can change manually or just edit the field note.txt file.

 

3/27/1999 11/10/2018     7,168.00
     
GPS Date: 3/27/1999 11/10/18

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PN-60 Owners;

Looks like Garmin has issued a firmware update to resolve the date problem.

 

         https://support.garmin.com/en-US/?faq=dXCDWk3aIZ3A0Ly9z8uym5

 

I contacted Garmin support to see if a similar update would be forthcoming for the PN-40 and below is their reply:

 

    Hello Ed

    Thank you for contacting Garmin Product Support and I am sorry you are experiencing an issue.

    At this time we are not looking on releasing a firmware update for that older DeLorme GPS device.  I apologize for the inconvenience.  

    I would recommend upgrading to a newer Garmin GPS device to meet your needs.
    https://buy.garmin.com/en-US/US/p/598455

    Regards,

    Kurt Ringrose
    Product Support, inReach
    Garmin International
    http://support.garmin.com

    >> Original Message ...
    >> From: (redacted)
    >> To: product.support@garmin.com
    >> Subject: Earthmate® PN-30/40 - firmware
    >> Sent: 24/12/2018 14:22
    >>
    >> I own two (2) Earthmate PN-40s. On or about 10/23/18, both of these began to display the current date as sometime in March, 1999.
    >> I see that Garmin has released a firmware update for the PN-60 units (Support Center>Earthmate® PN-60>firmware>Article>DeLorme PN-60
    >> Date and Time Issue). If Garmin has released a similar firmware update for the PN-40, where can I find it? If Garmin doesn't have a
    >> similar update, would you consider writing and releasing one?
    >> Thanks, Ed

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I have  PN20 and two PN60 units.

All went to March 1999 About Nov.1.

Generally Garmin don't give a hoot about us delorme owners.

They want us to toss them and buy a Garmin. They don't understand, if it ain't broke don't replace it. Besides I can do things with my delorme units that Garmin can't. Like have multiple geocache files and also delete individual waypoints and caches manually without connecting to a computer.

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1 hour ago, Mn-treker said:

They don't understand, if it ain't broke don't replace it.

 

And therein lies the rub, it is broken. 

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14 hours ago, VTEngr said:

PN-60 Owners;

Looks like Garmin has issued a firmware update to resolve the date problem.

Santa brought me a 66st. Our first day together today was not pleasant. I'm almost afraid to update my PN-60 firmware 'cuz it'll give me an excuse to ignore the 66st and keep using my PN-60. I might even risk installing it on my PN-40, just to see if anything interesting happens.

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14 hours ago, VTEngr said:

PN-60 Owners;

Looks like Garmin has issued a firmware update to resolve the date problem.

 

         https://support.garmin.com/en-US/?faq=dXCDWk3aIZ3A0Ly9z8uym5

The update takes a while, but it worked like a charm. One catch: I didn't bother to take the SD card out of my PN-60, and it turned out I needed to copy the update directory to my SD card in that case. When I copied it only to the internal memory, the update didn't happen.

 

Actually, my PN-60 is really a PN-60w, but there's no PN-60w download as there was for the 3.6 release. Since I don't actually use the "w", I didn't worry about it, and it doesn't appear to be a problem for me.

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9 hours ago, GeoTrekker26 said:

 

And therein lies the rub, it is broken. 

Actually it is not broken. Just a stupid method of programming for both the satellite and the receivers. Even though the date may be wrong. The units still work. I will try that update for my PN 60s

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1 hour ago, Mn-treker said:

Actually it is not broken. Just a stupid method of programming for both the satellite and the receivers. Even though the date may be wrong. The units still work. I will try that update for my PN 60s

I'm not sure how you're judging my unit as working. I use my PN-60 all the time to see tides and sunset. What they were in Spring 1999 is not very useful to me Winter 2018. I considered that very broken even though the unit could still load caches and take me to them.

 

Anyway, the new firmware fixed that problem. Too bad there's no firmware fix for DeLorme's junky USB wires. I figure I'm only a month or two away from a complete failure that will mean I can't connect my PN-60 to my computer. I'm pretty impressed Garmin released this firmware, and really glad VTEngr noticed and brought it to our attention, I'd be even more impressed if Garmin would sell some of those DeLorme USB cables.

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I have read about taking the head apart and doing a repair inside. Also those pins are spring loaded . Try air in a spray can and a little contact cleaner on cotton swab. Then clean the pads on the GPS. If you have a cigarette lighter 

Charger that is broken. Open it up, you will find a coil with broken wire going into the PC board. Fix that and good to go.

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14 hours ago, dprovan said:

I'm not sure how you're judging my unit as working. I use my PN-60 all the time to see tides and sunset. What they were in Spring 1999 is not very useful to me Winter 2018. I considered that very broken even though the unit could still load caches and take me to them.

 

Anyway, the new firmware fixed that problem. Too bad there's no firmware fix for DeLorme's junky USB wires. I figure I'm only a month or two away from a complete failure that will mean I can't connect my PN-60 to my computer. I'm pretty impressed Garmin released this firmware, and really glad VTEngr noticed and brought it to our attention, I'd be even more impressed if Garmin would sell some of those DeLorme USB cables.

As far as the sunset rise and tides go.

On that page you can change the date.

Change to a date in the future and see what will be. Change to a date in the past to see what was. I just ran the update on mine. All is well now 

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On 12/27/2018 at 10:22 AM, Mn-treker said:

I have read about taking the head apart and doing a repair inside. Also those pins are spring loaded . Try air in a spray can and a little contact cleaner on cotton swab. Then clean the pads on the GPS. If you have a cigarette lighter 

Charger that is broken. Open it up, you will find a coil with broken wire going into the PC board. Fix that and good to go.

Thanks, but my problem is the that wires tend to break. My last working USB cable now sometimes takes some fiddling with the wire to get the connection to work. It's not the pin problem.

 

It doesn't look to me like that's something I could fix myself, but I'd be happy to hear about it.

 

10 hours ago, Mn-treker said:

As far as the sunset rise and tides go.

On that page you can change the date.

Change to a date in the future and see what will be. Change to a date in the past to see what was. I just ran the update on mine. All is well now 

Yeah, changing the date on the tide or sun/moon screen sounded like an easy idea until I did it a few times. Changing every single digit with that rotary feature gets old fast, so I quickly stopped doing it for the casual "I wonder when the sun's going down today?" class question that I used to check on my clicking a couple buttons to bring up the screen. I did do it once when I really needed to know the current tides because if they were too high, there was no point in trying to get the cache.

 

So I'm really glad to have that glitch fixed even though I don't use it that often.

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Well what I would do is to open up the outer insulation. First inspect where it is possibly broken. Get some heat shrink tube. Slip it on the broken wire. Solder the broken part. Test the cable then if good slip tube over solder and shrink it. Possibly also have a larger piece  for the outer insulation. Or just electric tape.

To prevent from breaking again. Do not cooil the cable too tightly. That is the number one way they break.

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On 12/27/2018 at 1:22 PM, Mn-treker said:

I have read about taking the head apart and doing a repair inside. Also those pins are spring loaded . Try air in a spray can and a little contact cleaner on cotton swab. Then clean the pads on the GPS. If you have a cigarette lighter 

Charger that is broken. Open it up, you will find a coil with broken wire going into the PC board. Fix that and good to go.

 

I found the USB cable has two failure modes.  One involves the contact pins failure to make contact to the PN-xx receiver and the other is broken wires at the connector.  I corrected both issues by replacing the original pins with larger ones and at the same time added better strain relief using heat shrink tubing.  The larger pins have more contact area, longer plunger travel and less apt to sticking.  I modified both USB data and automobile power cables in 2012 and haven’t experienced any connection issue since.

 

Pin Comparison (2 Views).jpg

Final Sole Plate.jpg

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Now many days since I did the update to fix date issue in my PN60.

Garmin says they give no guarantee as

To it's performance. So far all is well.

I do recommend that update if you demand a correct date on your Delorme PN60. But I think that they are only offering the update for PN60. Remember to remove the SD card before you start. For those of us with this good and the map software TOPO USA or North America. Keep your eyes open for that map software to stop working. It may give find tab not initialized.  A magnetic declination up date is coming soon, due to the fast speed of magnetic north moving. But that update may not be able to go into our software. This update is not from Garmin. It is the feds, this has been in the news lately. I do not think that it will affect our gps units since they come off the sattelites.

 

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I have a PN-30 and a PN-60w that are both showing the wrong date. I found a link to this thread after searching the issue. My current version on the 60 is 3.4 so I'll be updating that one first. I'm relieved that Garmin didn't leave us hanging so kudos to them.

Edited by WeekNDHiker

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Well the update for the PN-60 went well. She's back to her old self again and seems to be just fine.....with the correct date!

 

Here's a page from Garmin for updating the PN-30/40 to Firmware 2.9.

 

READ THE INSTRUCTIONS CAREFULLY!! 

https://support.garmin.com/en-PH/?faq=xAEN2moO0n9pdrVHvjfse6

 

This update says it will erase the data from your device. That's probably why I didn't install the update last year. It also changes the way your device connects to XMap and TopoUSA for your Tracks and your Waypoints. All other transfers for maps and files remain the same.

 

Unfortunately after running the firmware install and rebooting it did NOT correct the date. So the PN-30 remains stuck in 1999. 

 

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On ‎1‎/‎21‎/‎2019 at 6:31 PM, WeekNDHiker said:

Well the update for the PN-60 went well. She's back to her old self again and seems to be just fine.....with the correct date!

 

Here's a page from Garmin for updating the PN-30/40 to Firmware 2.9.

 

READ THE INSTRUCTIONS CAREFULLY!! 

https://support.garmin.com/en-PH/?faq=xAEN2moO0n9pdrVHvjfse6

 

This update says it will erase the data from your device. That's probably why I didn't install the update last year. It also changes the way your device connects to XMap and TopoUSA for your Tracks and your Waypoints. All other transfers for maps and files remain the same.

 

Unfortunately after running the firmware install and rebooting it did NOT correct the date. So the PN-30 remains stuck in 1999. 

 

The PN-30/40 firmware in that article is from 2011, so this isn't a new version.

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