Got a Vista, have some fairly technical questions

[ejmct]

Thanks to the new $50 rebate, I recently upgraded my Garmin GPS II+ to a Vista. I am generally happy but I have some questions & observations.

 

1) The reception is not good at all compared to my II+. Even in moderate tree cover it may lose the signal. Is there anything that can be done to improve reception? Also, I have the Garmin case and it covers most of the unit. I'm not sure where the antenna is located inside the machine but I wonder if the case is negatively effecting my reception. Any thoughts?

 

2) I read on here that the electronic compass needs to be recalibrated whenever the batteries are replaced. In order to avoid looking like a complete fool in doing so, I put it on a flat table and turn it around twice. I figure that will also increase the accuracy since its not relying on me holding the unit perfectly flat.

That said, do I also need to calibrate the altimeter when I replace the batteries? I know my altimeter is off right now (never calibrated since I have not yet been in a place where I knew either my exact altitude or pressure) but I was wondering about the battery/altimeter relationship.

 

3) The electronic compass confuses me a little. By default I believe that the electronic compass takes over from the satellites when your speed drops below 10 MPH. I understand that, but does this also happen on the map page?

For example, I'm looking for a geocache. I'm running at 12 MPH and according to the map page of my Vista the cache is up ahead on my right. As long as I'm moving I always know where the cache is relative to my position. Now lets say I stop moving completely and I just stand still. I'm still looking at the map page...

1) It still shows the cache up ahead on my right because that's where it was relative to my position the last time I was moving, or

2) Does the electronic compass takes over? The Vista knows where the cache is and my exact last position. So if I stay in place but begin to turn left or right, will the map show the cache move relative to the new direction in which I'm pointed?

Without an electronic compass the GPS has no idea which direction I'm facing unless I'm actually moving. This makes it hard to find something when you're really close and not moving very much. But does the e-compass work on only the "compass" page or also on the map page?

I'm not sure if I'm explaining this clearly but hopefully someone will understand what I'm saying.

 

I appreciate any help on these questions.

Thanks!

[Kingsman]

Man, I never want to go jogging with you. The altimeter takes readings of ambient pressure. By calibrating, you are telling the unit where terra firma is. This is helpful if you are using a topographical map and referencing the altimeter with the depicted elevation. Just remember that pressure is constantly changing. To be absolutely accurate, you’d need to calibrate every hour or so.

[Kingsman]

Man, I never want to go jogging with you. The altimeter takes readings of ambient pressure. By calibrating, you are telling the unit where terra firma is. This is helpful if you are using a topographical map and referencing the altimeter with the depicted elevation. Just remember that pressure is constantly changing. To be absolutely accurate, you’d need to calibrate every hour or so.

[+apersson850]

They say I know a little about the Vista, so here we go:

 

1) The antenna is under the Garmin logo above the display. Thin, non-metallic cases will not degrade the performance significantly.

Hold the unit flat, a little in front of you, for best reception. Use it in Normal mode, not Battery save, when in difficult conditions. And yes, the antenna type in the Vista is inferior in reception, but very compact, compared to the one in a II+.

 

2) Different batteries have different magnetic properties. The unit compensates for that, but that requires that calibration is redone when you put in another kind of batteries.

The altimeter is something else. Changing the battery doesn't matter, but weather changes does. If you know nothing better, calibrate it against the GPS altitude, or let it run in Auto calibration mode. Then it will calibrate itself against the GPS altitude.

 

3) The electronic compass kicks in a certain time after that you've gone below a certain speed. Both the time and speed can be set as you like it.

The magnetic compass works on the map page too, that's right. You'll notice when it kicks in due to the little icon to the left of the options menu button.

 

If you look at the map page, with the magnetic compass on, and you turn around, the map will spin around too (assuming you are using it with Track up). If you set it to North up, you can spin as much as you want, and look even more stupid than when you calibrate the compass, without the map image changing at all. The display update rate will prevent it from spinning smoothly, but it will change.

 

Anders

 

[This message was edited by Anders on September 08, 2002 at 10:48 PM.]

[+apersson850]

They say I know a little about the Vista, so here we go:

 

1) The antenna is under the Garmin logo above the display. Thin, non-metallic cases will not degrade the performance significantly.

Hold the unit flat, a little in front of you, for best reception. Use it in Normal mode, not Battery save, when in difficult conditions. And yes, the antenna type in the Vista is inferior in reception, but very compact, compared to the one in a II+.

 

2) Different batteries have different magnetic properties. The unit compensates for that, but that requires that calibration is redone when you put in another kind of batteries.

The altimeter is something else. Changing the battery doesn't matter, but weather changes does. If you know nothing better, calibrate it against the GPS altitude, or let it run in Auto calibration mode. Then it will calibrate itself against the GPS altitude.

 

3) The electronic compass kicks in a certain time after that you've gone below a certain speed. Both the time and speed can be set as you like it.

The magnetic compass works on the map page too, that's right. You'll notice when it kicks in due to the little icon to the left of the options menu button.

 

If you look at the map page, with the magnetic compass on, and you turn around, the map will spin around too (assuming you are using it with Track up). If you set it to North up, you can spin as much as you want, and look even more stupid than when you calibrate the compass, without the map image changing at all. The display update rate will prevent it from spinning smoothly, but it will change.

 

Anders

 

[This message was edited by Anders on September 08, 2002 at 10:48 PM.]

[ejmct]

Thanks for the responses.

 

Follow up questions:

 

What does the "battery save" mode actually do?

 

So if I don't change the type of batteries I don't have to recalibrate the compass? If I had Duracells in there and I replace them with more Duracells I'm ok not recalibrating?

 

Here's what I decided to do about altimeter calibration. I just went to the beach (I live pretty close) and calibrated it about 6' as I was standing right at the water. Then I drove home quick like a bunny (before the weather changed ) and looked at the altitude at my house. Now I'm pretty sure that my home is at 485 feet. So each day before I leave my house I can calibrate to 485 feet and I should be ok regardless of changes in weather.

 

With my II+ I used to check my altitude whenever I was at a place where I knew actually the altitude (like at a highway sign that said "Elevation 4000 ft.") and I would notice that altitude using satellites would be off sometimes by several hundred feet (and it could be off in either direction).

So part of the reason I wanted the Vista was for the barometric altimeter. Is this *really* more accurate than using the satellites?

Just curious.

 

Thanks for the help!

[ejmct]

Thanks for the responses.

 

Follow up questions:

 

What does the "battery save" mode actually do?

 

So if I don't change the type of batteries I don't have to recalibrate the compass? If I had Duracells in there and I replace them with more Duracells I'm ok not recalibrating?

 

Here's what I decided to do about altimeter calibration. I just went to the beach (I live pretty close) and calibrated it about 6' as I was standing right at the water. Then I drove home quick like a bunny (before the weather changed ) and looked at the altitude at my house. Now I'm pretty sure that my home is at 485 feet. So each day before I leave my house I can calibrate to 485 feet and I should be ok regardless of changes in weather.

 

With my II+ I used to check my altitude whenever I was at a place where I knew actually the altitude (like at a highway sign that said "Elevation 4000 ft.") and I would notice that altitude using satellites would be off sometimes by several hundred feet (and it could be off in either direction).

So part of the reason I wanted the Vista was for the barometric altimeter. Is this *really* more accurate than using the satellites?

Just curious.

 

Thanks for the help!

[crr003]

ejmct,

 

This is what Garmin replied when I asked about battery saver:

 

"Power-save mode works by detecting if you are following a steady course/speed, if you are then the receiver switches off for a few seconds. The screen is updated as normal, based on this course and speed.

 

When the receiver switches back on the run-up position (a DR or Dead Reckoned position) is compared to the actual position, if they match the receiver switches off again, if they don't the receiver stays on until a 'steady state' is detected again.

 

The battery save mode is not really recommended for slow moving applications like walking, due to the slow speeds. "

 

Don't know about the other questions - I've got a Suunto Vector for all that

[crr003]

ejmct,

 

This is what Garmin replied when I asked about battery saver:

 

"Power-save mode works by detecting if you are following a steady course/speed, if you are then the receiver switches off for a few seconds. The screen is updated as normal, based on this course and speed.

 

When the receiver switches back on the run-up position (a DR or Dead Reckoned position) is compared to the actual position, if they match the receiver switches off again, if they don't the receiver stays on until a 'steady state' is detected again.

 

The battery save mode is not really recommended for slow moving applications like walking, due to the slow speeds. "

 

Don't know about the other questions - I've got a Suunto Vector for all that

[+apersson850]

I've noticed that the battery save mode does turn off the receiver for a few seconds, then turn it on again, goes back to sleep and so on. But I didn't know myself that there is some more or less smart strategy in determining when it isn't needed. You always learn something!

 

If you use the same type of batteries, and we assume they are homogenous, so a rotaion of them wouldn't make any difference, then there is no need to recalibrate when replacing the batteries.

 

I do the same as you do, but I've checked the elevation of my house against a triangulated elevation marker nearby.

 

Ha-ha, you are splitting hairs now, aren't you? In the short run, after a calibration, there is no doubt about that the barometric altimeter is more accurate. Weather changes is a problem, of course.

For casual use, I think autocalibration works well. The degree of influence it has decreases exponentially (so they say), meaning that it makes a substantial contribution when turning on the unit, but after a while just compensates a little, to keep the air pressure away from inducing too much errors.

So, this means that it's not that 100% weather dependent, but still will not suddenly jump away, just because you lost a satellite and got another one.

 

Anders

[ejmct]

Thanks everybody for the responses.

I think the Vista is good little unit with some nice touches.

The only downsides I can find are the weak antenna and the cost of the Mapsource CD's.

[+apersson850]

If you want about the same features, but a more sensitive antenna, there is the GPSMAP 76S. It has virtually the same features, but a quad-helix antenna. It does go with a bulkier size, though.

 

Anders

[ejmct]

Thanks Anders -

 

Whats the cost differential between the Vista & 76S?

[+apersson850]

Garmin's suggested retail prices are $375 vs. $482, so the 76S costs you somewhat more. Various dealers may have various prices.

 

Anders

[shabbasuraj]

I met a Garmin salesperson and the only difference between the 76S and the vista is form factor, where you live the USA the price diff should be $100 for the 76S.

 

and ye the cds are expensive, especially the CDN mapsource bluechart ones...

 

garmin salesperson said the "dadgum CDN gov. is witholding the required info and charging an arm and a leg for the required maps...."

 

pathetic.

 

great for the gov, but not for Canadians....

 

lates...

[+apersson850]

quote:

---

Originally posted by shabbasuraj:

I met a Garmin salesperson and the only difference between the 76S and the vista is form factor

---

 

Not really true, since there are some slight variations in what's implemented in the firmware. The hardware seems to be equivalent, if not equal.

 

Anders

[shabbasuraj]

form factor simply replies to differences in "packaging of the unit" all hardware in terms of end user benefit is the same.

 

lates...

[+apersson850]

On that I agree 100%. What I referred to is that there are some implementation differences, when it comes to how this hardware is utilized.

 

The 76S does have a beeper, while the Vista is silent. But otherwise, the 76S is a little more marine, judging from the features it has (tide prediction, anchor drag).

 

Anders

[shabbasuraj]

yes anchor drag can be a useful feature for all units, that are bluechart compatible...

 

lates...

[+Prime Suspect]

quote:

---

Originally posted by ejmct:

1) The reception is not good at all compared to my II+.

---

Upgrade to the latest OS. They did something a few releases back that made a noticable difference under heave cover.

 

quote:

---

2) I read on here that the electronic compass needs to be recalibrated whenever the batteries are replaced.

---

It's better to do it outdoors, away from any metal objects. You'll know if you need to recalibrate if you have difficulty getting the unit to show that it's being held level.

 

You do NOT need to recalibrate the altimeter after changing batteries. At least, you don't if you're running a recent OS release (another reason to upgrade). By default, the unit uses automatic zone calibration. I've left this as is, and whenever I've been able to compare my alititide against a known value, my Vista has never varied by more than a few feet.

quote:

---

The electronic compass confuses me a little. By default I believe that the electronic compass takes over from the satellites when your speed drops below 10 MPH. I understand that, but does this also happen on the map page?

---

Yup (though when and if the compass takes over is user-settable).

 

[+Ish-n-Isha]

The Vista is Quite accurate with good signal, but not the best unit for tree canopy reception.

If you can stand the extra weight and bulk, the 76S is really the way to go. It also has a external antenna option you can use when you need to pull out all the stops. The coolest feature on each of them is the compass. In map mode, when a bunch of us are racing to a cache, the Vista wins most of the time because of the direct to cache track. We are usually checking for travel bugs wile the others are circling around.