Oh no, another GPS Question

I've had a Garmin 76CSx for a while that I use for sea kayaking (where it never loses its satellite fix) but have recently brought it hiking. I tried a search in VFTT but was unable to narrow it down to an answer to my question.

My question: In the mountains, my 76CSx, no surprise, sometimes loses the fix due to cover/terrain and, thus, understates the distance traveled. Is it possible to determine, by reviewing the track data, where and how much distance was lost? The mapped track typically shows end points accurately.
Thanking experts in advance!

I had this problem too but I solved it by leaving the gps at home in a drawer.

JK. Try configuring your unit to record trackpoints by distance and reduce the separation between TP's so they are close together.

I have a 60CSx and have yet to lose a satellite lock hiking the NH48. I have noticed the trip meter distance reads low, especially when climbing steep sections. I suspect when your speed is very low and records this as stopped time. Apparently the trip meter is based on your GPS measured speed while the track distance is based on the distance traveled. When I load the track on my computer the distance traveled is accurately reported.

Oh no, another GPS answer!

The GPS computes its position once per second and uses this to run the odometer function. I believe it skips breaks in the track.

If you download the track to a program, some programs will connect the ends of gaps and treat the track as a single continuous track. I think MapSource treats it as separate tracks and NG TOPO! treats it as a single track. (MapSource also has some track editing functions which may enable you to join segments. I haven't used them so I can't give you any details.)

One thing that you can definitely do is to save the track in GPX format. This is a text format that you can edit with a standard text editor. The GPX format is pretty obvious after you look at a track or two.


I don't know how you are carrying the GPS. If you are not carrying it well, you may be able to reduce the number of breaks in the track. The 76CSx works best in a vertical position. Also your body and possibly some of the contents in your pack may block the signals, so carry the GPS as high and as clear as is practical. For instance carry it vertically in the top of your pack or vertically in a small pocket attached to your shoulder strap. (Dry pack fabric will not weaken the signal so inside a top pocket is ok.) For the absolute best, use an external antenna in the top of your hat or above your head on a pole attached to your pack. (If I am just hiking, I use the strap pocket or high in the pack. If I am mapping a trail, I use an external antenna in my hat.)


OldMan brings up a good point: the GPS has speed thresholds to separate "moving" from "stopped". Your GPS may think you are stopped when you are moving slowly. You can set these thresholds (somewhere in the setup menus) and might try lowering the thresholds.

Doug

Thanks so much for your inputs.
I will try repositioning the GPS as I hike and play with the .gpx format, in which I have previously saved most of my trips for input into Sport Tracks.

RickB. said:

Thanks so much for your inputs.
I will try repositioning the GPS as I hike and play with the .gpx format, in which I have previously saved most of my trips for input into Sport Tracks.

Click to expand...

You can convert pretty much any existing track to gpx if need be.
GPSBabel (and many other programs) can do it. http://www.gpsbabel.org/

Doug

In digging through some of my stuff, I found an old camera/binocular case, perfect size, that will affix nicely at the top of my shoulder strap. It is Cordera-like nylon with a thin, soft lining (to protect lens). Is that likely to affect the signal significantly?
Thanks.

Sorry, RickB, but that probably won't help much

RickB. said:

In digging through some of my stuff, I found an old camera/binocular case, perfect size, that will affix nicely at the top of my shoulder strap. It is Cordera-like nylon with a thin, soft lining (to protect lens). Is that likely to affect the signal significantly?
Thanks.

Click to expand...

Dry fabric is not a problem.

Doug

RickB. said:

In digging through some of my stuff, I found an old camera/binocular case, perfect size, that will affix nicely at the top of my shoulder strap. It is Cordera-like nylon with a thin, soft lining (to protect lens). Is that likely to affect the signal significantly?
Thanks.

Click to expand...

Garmin also has a nice rotating clip that I use on my sternum strap...Very convenient...I've never lost a signal w/ my 60CSX Although I don't know if it will fit a 76

Hikes4fun said:

Garmin also has a nice rotating clip that I use on my sternum strap...Very convenient...I've never lost a signal w/ my 60CSX Although I don't know if it will fit a 76

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I think it is 60 series specific.

There is a hazard with that clip--if you snag the GPS while using it, you can break the case. I have removed my clip.

Doug

You are correct--it is specific--I can see how snagging might happen, but I've never had a problem..even when HH 'wackin etc...Then again I usually lead w/ my head

DougPaul said:

I think it is 60 series specific.

Click to expand...

The clip wears out rather fast, IMHO.

Hikes4fun said:

You are correct--it is specific--I can see how snagging might happen, but I've never had a problem..even when HH 'wackin etc...Then again I usually lead w/ my head

Click to expand...

If it breaks, it will expose the electronics to the elements. Not worth the risk, IMO.

Doug

I have been using the Garmin GPS Map 76 Cx for quite a while and have had good luck with the case that Garmin sells, that goes on your belt, or other convenient place. If you are in thick woods on a rainy day, using a remote hi gain antenna (Garmin GA25MCX) makes a big difference. It has a magnetic base, so I sewed a piece of sheeet steel onto the top of my hat. It works great, and you can put the GPS anywhere you want. I still use the Garmin belt case. If you happen to snag the antenna cable, it pulls the antenna off the plate before damage is done, so far. If people ask you about the antenna on your head, you can say "I must be in contact with the direktor". They won't ask much more of you.

Trail Bandit said:

I have been using the Garmin GPS Map 76 Cx for quite a while and have had good luck with the case that Garmin sells, that goes on your belt, or other convenient place.

Click to expand...

If you carry a GPS on your belt, your body will block out ~half the sky and can degrade the performance of the GPS. I suggest that you carry the GPS high on a pack strap or in the top of your pack to reduce the signal blocking by your body.

Some GPS belt clips (eg the one on my eTrex Vista case) can fit on the adjusting strap at the back of a baseball cap. Almost as good as the antenna on top of one's hat.

Of course, if you use an external antenna, it is the antenna location that counts and you can put the GPS anywhere.

It's all about a clear skyview...


I hear aluminum foil hats can also reduce the number of people bothering one, too... (Just put the GPS antenna on top of the aluminum foil.)

Doug

DougPaul said:

If it breaks, it will expose the electronics to the elements. Not worth the risk, IMO.

Doug

Click to expand...

Not sure what 60Csx and clip you're looking at, but I doubt the case will break..the clip maybe but certainly not the case

Hikes4fun said:

Not sure what 60Csx and clip you're looking at, but I doubt the case will break..the clip maybe but certainly not the case

Click to expand...

You are welcome to your opinion, but I've read reports of it actually happening.

Doug