Antenna or Not?

[+Bushrod]

I was wanting to use my 76csx in my truck for some off-road camping.Everyone is saying I should get a external antenna to hook to my gps since I will be using it inside the truck.My question is why should I use a external antenna if the gps is doing fine without one?I have checked it out and its working fine as is.

[planewood]

I was wanting to use my 76csx in my truck for some off-road camping.Everyone is saying I should get a external antenna to hook to my gps since I will be using it inside the truck.My question is why should I use a external antenna if the gps is doing fine without one?I have checked it out and its working fine as is.

 

Bushrod - here's something you can try. Without an antenna, turn your GPSr tracking on for a few short trips. Scatter these over several days and different times of the day. Then, upload these saved tracks to Google Earth and plot them out. Examine them closely in GE and make your own detrmination as to whether they follow the actual routes to your satisfaction. Hopefully the Google Earth images will be registered adequately in your area.

 

If you can borrow an antenna from a friend for a few days, then try running the tests again and compare them to the earlier tracks.

 

Then, make your own decision. Everyone's needs are different and what's good for one may not be good for another.

[+Prime Suspect]

I was wanting to use my 76csx in my truck for some off-road camping.Everyone is saying I should get a external antenna to hook to my gps since I will be using it inside the truck.My question is why should I use a external antenna if the gps is doing fine without one?I have checked it out and its working fine as is.

Unless you have a metalized windshield (and you probably don't), you don't need an external antenna. If you're getting a decent lock, you're fine.

[+NightPilot]

If it works, it works. I use an external antenna on my truck, but I need it. My GPS in there is an old Radio Shack Digitraveler, and it's stuck inside a storage compartment behind and underneath the seats. It won't get a signal down there without an external antenna. I have it connected to a bluetooth adapter, for connecting to my Palm. That's certainly not a common setup, though, and the most common is just a GPS on the dash, which I also use now and then. That works just fine.

[bibbins]

I recently purchased a Garmin GPSMAP 60 CSx. I like to put it on the console of my truck when traveling in it. With my external antenna it is showing me accuracy of 10 feet regularly. Is that accurate? I have no real idea but I do believe it is much better than without it. By using the antenna I can have the GPS much closer to me and see it much better.

[+Red90]

For normal auto use, definitely no. The reception on these units is very good and accuracy will always be better than the road size or maps.

 

If you are making maps, it is worth it.

 

Regardless, an antenna does only cost around $20, so it is not a big expense.

[TeamCypherX]

I have an external antenna for my quest, but I really don't think I need it. With the antenna attached, I can get 8' accuracy. That's great, but isn't needed for auto routing. Since I have the road lock turned on, all I need is the standard 20' accuracy I can get with the built in antenna.

 

In use my 60csx in my jeep when I'm offroading. Absolutely no need for an external antenna with the X-units. They get great reception even inside a vehicle.

[+Prime Suspect]

I recently purchased a Garmin GPSMAP 60 CSx. I like to put it on the console of my truck when traveling in it. With my external antenna it is showing me accuracy of 10 feet regularly. Is that accurate? I have no real idea but I do believe it is much better than without it. By using the antenna I can have the GPS much closer to me and see it much better.

10' is good, but I get that or better just using the built-in antenna. But if it lets you see it better, that's a safety issue, and certainly worth it.

[WR8Y]

 

Bushrod - here's something you can try. Without an antenna, turn your GPSr tracking on for a few short trips. Scatter these over several days and different times of the day. Then, upload these saved tracks to Google Earth and plot them out. Examine them closely in GE and make your own detrmination as to whether they follow the actual routes to your satisfaction. Hopefully the Google Earth images will be registered adequately in your area.

 

If you can borrow an antenna from a friend for a few days, then try running the tests again and compare them to the earlier tracks.

 

Then, make your own decision. Everyone's needs are different and what's good for one may not be good for another.

 

Good, reasonable advice.

 

Why the bold above? Well, remember, there are times when as little as 5 birds will be there for you. If your roof blocks the signal of 1, 2 or 3 of them, your accuracy will be poor.

 

I always run an antenna on my truck (a Ford Ranger) as the windshield area is small and low and the GPSr's view of the sky is limited. When in my Durango, it seems the external antenna is seldom needed.

 

Anyway...

With an external antenna costing less than $30 from various sources - why would someone NOT have one?

Edited March 2, 2007 by WR8Y

[planewood]

Good, reasonable advice.

 

Why the bold above? Well, remember, there are times when as little as 5 birds will be there for you. If your roof blocks the signal of 1, 2 or 3 of them, your accuracy will be poor.

 

I always run an antenna on my truck (a Ford Ranger) as the windshield area is small and low and the GPSr's view of the sky is limited. When in my Durango, it seems the external antenna is seldom needed.

 

Anyway...

With an external antenna costing less than $30 from various sources - why would someone NOT have one?

 

I bought my 60cx to find old surveyed property corners in heavily wooded & hilly country. The Gillson antenna definitely helped there. I do get better tracks when cruisin down an interstate, but does one really need an antenna there? I think I paid $20+ for the Gillson, so that was a no-brainer.

 

ps - I found the starting point stake from the old survey, then used the 60cx to project the distance and bearings to lat/lon for all the other corner points. The cost of the 60cx was worth it for just that one job. It got me to within 8'-10' of each of the old stakes. Some of the points were projected 1/2 mile. Most of the stakes were showing above ground only about 1" and all were covered with leaves.

 

I also used GeoCalc to calculate the projections and got the same answers as did the 60cx.

[+Red90]

A little off topic...

 

But I was recently playing with projections. The on unit projections use a spherical earth model with the radius set as the datum major axis. This is less accurate than projections using the ellipsoid calculations and the difference can be up to 0.3%. Just a note to be careful on long projections as you will get outside of the reasonable search accuracy.

[WR8Y]

I do get better tracks when cruisin down an interstate, but does one really need an antenna there?

 

Well, in southern Georiga (or similar places) where the sky is "open", I'd say not.

But travel around the hills or mountains of Tennesee, etc., and I think the external antenna can help as any birds that are low on the horizon are "not there for you"; so you really do need a good shot at what birds ARE there.

 

That's my thoughts, anyway.