HomeHardware


Need laptop GPS sensitive enough to work in canyons, hills, under trees
Frog
I am currently using an EverMore BT-R900. I have noticed a little bit of a problem when I am moving in canyons, hills, trees, yet my handheld Garmin eTrex Vista does not have any problems. From what I have read, I would not expect these problems from this unit, or am I expecting too much from this unit. I am considering a new receiver. Having read many pages here, I am considering the BT-Q818X, but perhaps an outside mount like one of the GlobalSats might be in order. Does anyone have any recommendations? I am using MS Streets and Trips 2010 (And like it very much).
tcassidy
Assuming you have Bluetooth on your laptop, the 818x should be an excellent GPS device. Possibly close to the equal of your eTrex. If you are considering using it as a USB device, it will not work directly with Streets & Trips as its USB data rate will be 115,200 bps, far exceeding S&T limit of 4800 bps. This is not an issue with Bluetooth.

Terry
Ken in Regina
Frog,

You didn't specify how you use/mount the two devices.

If you are using your eTrex handheld away from the vehicle but your EverMore is always sitting, say, on the dash, it's not a fair comparison.

If you place the eTrex in the same location as the EverMore normally sits in these situations, does it still work better than the EverMore?

Conversely, if you take the EverMore outside the vehicle in the same way you probably use the eTrex, does the eTrex still work better than the EverMore?

No matter where you place a GPS receiver inside a vehicle, the vehicle roof and side pillars will always block the reception from some of the available satellites. So it's important to know whether the better performance of the eTrex is because of its technology or simply because the way you use it gives it a better view of all possible satellites. Or possibly a bit of both.

It's important to know that the comparison is exactly apples to apples before any recommendations will be very useful to you.

Which eTrex Legend model do you have? The older Legend or Legend C? Or the newer Legend H or HCx?

...ken...
tcassidy
The Evermore is a SirfStar III receiver, a very reliable device. However, there are more modern GPS chipsets. The BT-818x for example, uses the MTK 2 chipset which is at least 2 generations newer. It should work better in adverse conditions than the Evermore and have improved battery life.

As Ken suggests, placement of the receiver is as important as the device itself.

Terry
Frog
Quote:
Originally Posted by Ken in Regina
Frog,

You didn't specify how you use/mount the two devices.

Which eTrex Legend model do you have? The older Legend or Legend C? Or the newer Legend H or HCx?

...ken...
Sorry about that, Ken. A very good question when doing comparisons.

When I started noticing the problems I switched to the eTrex using National Geographic Topo. When I did not have any problems, I did a side-by-side comparison on the hood of my truck, with the Garmin disconnected. Granted, I was in a pretty good valley, the northern most marker a, and the satellite lock took some time, but the Garmin did lock, the EverMore never did.

On my second comparison both were side by side on the dashboard in the southern marker b. This time both did lock, but the Garmin was much quicker, about 50 seconds. The EverMore was about 90 seconds.

As far as the model of my eTrex, it is the original eTrex Vista.
I know it is a little old, but as long as I have my map and compass as backup, it keeps me safe and in the right direction.

Attached Images
area1_a-b.jpg  
Frog
Quote:
Originally Posted by tcassidy
Assuming you have Bluetooth on your laptop, the 818x should be an excellent GPS device. Possibly close to the equal of your eTrex. If you are considering using it as a USB device, it will not work directly with Streets & Trips as its USB data rate will be 115,200 bps, far exceeding S&T limit of 4800 bps. This is not an issue with Bluetooth.

Terry
Thank for telling me about the USB rate problem. I thought I had read where that could be modified via utilities provided. I really would like both BT and USB support for S&T. That is something I am going to have to think about.
I am curious what you think about an external mount. Ken's comment on the "shell effect" has me thinking.
tcassidy
GPS Gate can be used to reduce the data rate of the 818x when used in USB mode. It will translate the 115,200 bps of the GPS to a data rate S&T will work with (4800 bps). The utilities provided with the GPS will only modify the refresh rate. That must set be a 1 Hz for S&T.

I wouldn't consider your Evermore or the QStarz for external mounting. Neither is waterproof. The QStarz model requires less signal than the Evermore and locks faster so the improvement, even on the dash would be noticable in adverse conditions. If your older ETrex can obtain lock, I'm sure the QStarz will too.

If you think external mounting is the answer, consider the Globalsat USB BU-353. It is SirfStar III as is your Evermore but also magnetic and waterproof. Outside mounting is not a problem for that GPS.

Terry
Ken in Regina
From the topo map it's obvious why the differences in getting a lock between the two locations. Location "a" will be much more difficult than location "b". Having said that, if your original Legend is getting a lock in those locations you should be able to get a lock as quickly in similar locations with something like the BU-353 that Terry mentioned.

In situations like Location "a", mounting outside on the roof makes a huge difference. In the Canadian Rockies there's a place called 3 Valley Gap where I lose reception with anything mounted inside the vehicle but with my external antenna on the roof I can still maintain a three-satellite lock through there.

...ken...
Frog
Thanks so much, I'll have a look at the BU-353.
malaki86
I use a BU-353 in my truck (18 wheeler). It's mounted on a ledge on the passenger door. The ONLY time I lose a GPS lock is when I go through tunnels. I travel all over the US and don't have any issues with it whatsoever. We're based in West Virginia, and there are quite a few deep, narrow valleys that I travel through on a regular basis. These can be lines with cliffs and overhanging trees with a perfect signal.
Frog
From everything I have read, the advice I received, and malaki86's experience, it looks like the BU-353 is the solution to my problem. I will pick one up, and give it a good test drive.

I do have one question regarding running the cable through the cab of my truck. I would like to run it out the rear drain port with an O-ring seal, and then up to my roof. To do this I will need at minimum a 6 foot USB extension, perhaps more, in order to hide it and keep it out of the way. Has anyone run a standard USB extension, or will I need to use an Active Repeater Cable?
tcassidy
A 6 foot USB extension cable should not pose any problems with the digital signal. If you are concerned, make sure you get a good quality extension (not one from a dollar store). How do you plan getting the USB connector through an o ring seal? It is permanently connected.

Terry
tcassidy
Maybe you are thinking of an GPS active antenna These generally come with an mcx connector not much larger than the cable. Unfortunately, not many GPS receivers have a port for them. I know my Holux GPSlim 236 does but the ones discussed here do not.

Terry
Frog
Quote:
Originally Posted by tcassidy
A 6 foot USB extension cable should not pose any problems with the digital signal. If you are concerned, make sure you get a good quality extension (not one from a dollar store). How do you plan getting the USB connector through an o ring seal? It is permanently connected.

Terry
Sorry I did not explain myself better. I have included the best image I could find. I was going to use the drain in the back of the cab. However, looking at my Chilton, I found an electrical access under the front carpet.

It does have an electrical pass-through plug and is large enough for the USB head to pass through. I will pass the cable backwards from the antenna into the cab. If I put the connection to the extension cable on the outside of the cab, I will be able to take the GPS unit in. Obviously, I will have to waterproof this connection. (I will have to think a little on that one.) If I put an insulating cover over the USB cable, I can follow my electrical conduit from the rear of the cab, then up into the cab. The other end would lead to the top between the cab and the bed of the truck.

As you can tell, I really want to keep the antenna cable out of the way, and looking good. So, do you see any problems with this theory? (Please list them in level of importance.)

Passing the cable through the window just seemed too easy. LOL
Attached Images
floorboard-passthrough.jpg  
tcassidy
Sounds good to me. The 353 is small and wouldn't attract much attention on the cab roof but a way to remove it temporarily is always safer.

I can't quite visualize how the 353's 5 foot cable would reach from the roof to a convenient cross connect point and stay hidden. But I was never very good at visualizing anyway! When I used an active antenna, the hood or cowl was good enough and I could just slip it under the hood when not in use.

Terry
laptopgpsworld.com About