Beware Garmin GPS 72

[Emil Maurer]

I loaded fresh batteries into my Garmin GPSMap 76 for the first time this spring, yesterday and after booting up and getting a fix, the image on the screen convulsed and vanished leaving a single black line and inoperative control buttons. I gather I have the same problem with WAAS enabled that you describe with the GPS72.
It was reassuring to read about the symptom and realize that the unit had not died an early death so soon out of warranty.
I was contemplating $89 for a repair versus $162 for a new unit or perhaps both so as to have a backup. I discovered this loss after finding that my Guest battery charging unit wasn't lighting up and probaly requires replacing.
Like they say in Abbasynia, "If it ain't one thing its the other."

[Joe Myerson]

Emile,

This is scary news for me as my "main" GPS is a Garmin GPSMap 76, while my backup is a plain, old GPS 76.

Of course, when daysailing in familiar waters, I only use them to determine my speed over ground.

BTW, I had a couple of moments during last year's sailing season when my screen went blank, except for that single black line, only to come right back. Could that have been the beginning of the WAAS software problem?

--Joe

[Breault5]

Am I correct in assuming if I simply disable the WAAS feature on my new Garmin 72, it should work fine other than not being as accurate. I read in this post the accuracy is merely a 2' difference. I think I could work with that... Since the "72" is new to me I have not loaded any waypoints as of yet, so I should have no worries there as well, as far as losing data. Right???

[John Vigor]

Am I correct in assuming if I simply disable the WAAS feature on my new Garmin 72, it should work fine other than not being as accurate. I read in this post the accuracy is merely a 2' difference. I think I could work with that... Since the "72" is new to me I have not loaded any waypoints as of yet, so I should have no worries there as well, as far as losing data. Right???

That's what Garmin told me. Just disable WAAS and the rest will work OK. But I have doubts about the amounts of accuracy quoted. Who would have spent all that time and money setting up WAAS if the difference was only 2 feet?

As for waypoints, I personally am holding off as long as I can. Garmin says it will post a downloadable fix on its website as soon as possible. From bitter experience, I wouldn't trust this download not to erase all my settings and waypoints. If you never want to use WAAS, and therefore won't be downloading the fix, you should be able to load all the waypoints you need. But I'd give Garmin tech support a call if I were you.

Cheers,

John Vigor

[Sea Owl]

All;

Having done some nosing around, 'straight' GPS is supposed to give a position to +/- 15 meters (48.75 feet).

WAAS GPS is rated to give a position to +/- 7 meters (24.7 feet).

These are both 'rated' values. WAAS enabled actual performance measurements of system at specific locations have been reported that shows it typically provides better than 1.0 meters laterally and 1.5 meters vertically throughout most of the contiguous United States and large parts of Canada and Alaska. It should also be noted that the WAAS plus up was really oriented towards the aviation industry.

Taking the rated value, 'straight' GPS is no doubt great to get you into the yacht harbor, and certainly close to home.

Running a 20' wide channel with shallow water on each side in poor visibility....hmmmm....

Anyway, as with all things, depending on what you are using it for, there are some 'hard' numbers to think about.

Fair winds to all, and let the season begin!

[Joe CD MS 300]

After doing some quick checking on some other websites and blogs it seems as if the changes in the WAAS system and or satellites has affected models of other manufacturers, Saw some issues with Trimble, Raymarine and Magellan. Doesn't appear to be widespread however and only an issue with specific models. Seems like it is a good idea to check any handhelds at hone before hitting the water. I am going to check my GPSMAP 76 which is in the same family with the 72. My GPSMap 478 has been working fine.

[chase]

Just in case this thread was a dream, I turned on my Garmin 72 while at the coast this weekend. Same program, long line, disable WAAS, works fine.

John, as chair of the ad hoc Garmin GPS 72 WAAS update committee we'll look forward to your findings.

Chase

[Joe CD MS 300]

John, Chase,

Just tried out my GPSMAP 76 for the first time in 8-9 months, WAAS was enabled. Didn't have any problems, it was on for about 1 hour. How ling before your problems appeared?

Joe

[chase]

Joe,

As soon as it aquired it went to the blank screen with the long line.

c

[mgphl52]

The way I read the NTM, there is a specific area (about 35 nm radius, I think) that would be affected. I don't remember the LAT/LONG but it sounds like some of you are definitely in that space.

-michael

[John Vigor]

Michael, you're confusing things terribly. Read Jim Davis's post again slowly and carefully. That interference with the GPS signal is another matter entirely and affects only a limited area of Chesapeake Bay.

The WAAS problem is nationwide and ongoing. Garmin still has not come up with a fix, so the temporary fix is simply to "disenable" the WAAS function on your Garmin GPS 72 or lower-end 76. Not all model 76s are affected apparently, but all new 72s are for sure, and many older ones, too.

John Vigor

[mgphl52]

My apologies. I'll test my own GPS76 - once we get moved to Biloxi (tomorrow) and, when I find it again (who knows when...).

[John Vigor]

Thanks, Michael, be sure to let us know how the test goes when you find your gps. Make certain WAAS is enabled, and see what happens. Even if it is one of the vulnerable models, it could take some time to crash. It has first to lock onto a WAAS-enabled satellite, apparently, and because the powers-that-be changed the characteristics of those satellite signals recently, they cause the gps to crash. You will know you're receiving WAAS data when the Information Page shows the receiver status as 2D or 3D Differential Location and little "D"s appear in the bars that indicate satellite strength.

So to update what we know:

If your GPS suddenly crashes, leaving only one vertical line from top to bottom of the screen and no buttons working, remove a battery briefly and then replace it.

The machine will now boot up normally again.

Quickly, before it can lock onto another WAAS satellite, scroll through your options and disable WAAS.

On the 72 you can gain a little time to fossick around trying to find out how to disable WAAS by going straight into Simulator mode: Switch on, press Page, Page, Menu, and Enter. In this mode, the WAAS satellite will not connect, but you can work through the menus to disable WAAS. (Do not forget to leave simulator mode afterward if you're trying to navigate, of course.)

Once WAAS is disabled, the receiver will work reliably again--but not as accurately.

Incidentally, Garmin now tells me I will need two connector cables to download the corrected software (when they come up with it) to my brand-new GPS 72. I can see the need for one cable to connect the gps to my computer. Does anyone know what the other one might be for? A jolt of 110-volt AC to liven things up, maybe?

Cheers,

John Vigor

[Joe CD MS 300]

John,

It may not be that you need 2 cables, I think that it may be that there are two types available: one for a serial port and another for a USB port. With my GPSMAP 76 I use a Serial cable and with the GPSMap the USB cable. The USB cable is actually the same as you get with many digital camers as the unit itself has the same type of connection as many cameras. It might be called a mini-USB connection. On the GPS 72 a Garmin USB cable would be needed because of the specific port on the unit.

Joe

[John Vigor]

Joe,

Garmin is sending me two cables so I can fix my brand-new GPS 72, and this is what they tell me:

"You’ll have to daisy chain the two cords together, then connect the PC Interface cable to your device, and the USB converter cable to your computer…and you should be good to go."

Sounds a bit clunky-dory to me, but what would I know?

Cheers,

John Vigor