Jump to content

External Antenna


dusty280

Recommended Posts

I have a Garmin GPSMAP 76S. Since I updated the software to the latest version 3.6 I have been happy with the unit. Does anyone have experience with the optional external antennas? Do they help? On clear days I can get down to 9-12 ft. On cloudy days 20-30Ft. Does the external antenna help those numbers? Can they be used walking through the woods? Or does it only help in big cities with lots of tall buildings? Any feedback would be appreicated.

Link to comment

I sometimes use my Gilsson external with my eMap and it would also be compatible with the 76S (and 60, 76c/cs). The Gilsson costs about $20. The main benefit of the external antenna is that you can position it for optimal skyview and carry the GPS in a way that's convenient - like inside a pocket, horizontally so the magetic compass works, etc. without worrying about how it will affect reception. I use it when hiking if I want to get a good tracklog for mapping later. I sewed a little piece of cloth inside my hiking cap to act as a pocket for the antenna. That way it's pretty unobtrusive and in a position where it's not blocked at all by my body.

 

It won't help much in situations where you already get good reception, but can make a big difference when the reception is marginal.

Link to comment

I used my new Glisson external antenna for the first time geocaching with my 60CS yesterday. It does pull in a much stronger signal -- more satellites and higher bars! But, I didn't pay attention to how many feet it was down to.

 

I have a cap that has a pocket (keys/change?) in it and I put the antenna in that. I'm sure I looked like a geek, but... :rolleyes:

Edited by Cabinwood
Link to comment

Thanks for the responses. It looks like it definitely aids reception. The Gilsson also seems to be quite a bit cheaper than the Garmin product. Does anyone have experience with both? It would seem to be a big advantage as when the leaves are on the trees, it is sometimes hard to get a good signal. Thanks for all the help.

Link to comment

I have a Garmin V with and an external antenna. The only time I have used the external antenna has been when I fly. It allows me to position the antenna near the window and not have to hold GPS up against the window the entire flight. Other than flights I have never had a need for it even though it is always in my gear bag.

Link to comment
On clear days I can get down to 9-12 ft. On cloudy days 20-30Ft.

 

Huh?!? Really? I have never, in 7 years of using these things, seen a degredation of accuracy due to weather! I have used them under clouds, in rain, in fog, in snow...You name it. Externals really do aid in grabbing satellite signals, but overall, they usually aren't necessary in normal conditions. They cause a little extra battery drain also. The Garmins are too expensive.

Edited by Alphawolf
Link to comment

There are several threads on this. Clouds don't affect GPS signals at all. Satellite geometry does, and this can cause some confusion. An external antenna will give better signal strength, which may help in difficult conditions. I use a reradiating antenna that uses its own batteries, and doesn't draw down the GPS batteries at all. It's the only thing that will work on the eTrex series. As for carrying it, it has magnets in the base, and I attached a large steel washer to the top of a standard hard hat with very strong mounting tape. It holds the antenna very securely, and also protects my head from the thorns and briars when I'm pushing through them after Captain J's caches. When I get back to the car, I can stick the antenna on top of my cachemobile and not have to keep my GPS in the windshield for driving directions.

Link to comment

Thanks for the responses. Maybe it is the position of the satellites that is causing different accuracy readings. Maybe is was just chance that when the reception was bad that it was always cloudy. My battery life in cold weather is not very good with the 76S, an external that runs off its own battery really appeals to me. I have found that when I am getting 10-12 feet readings that my ability to find caches goes up considerabely over my ability to find things when it is at 25-30 feet.

Thanks.

Link to comment
I used my new Glisson external antenna for the first time geocaching with my 60CS yesterday. It does pull in a much stronger signal -- more satellites and higher bars! But, I didn't pay attention to how many feet it was down to.

 

I have a cap that has a pocket (keys/change?) in it and I put the antenna in that. I'm sure I looked like a geek, but... :)

Did you peel off the little bits off of the back and remove the little bar magnets?

 

I found that the magnets were interfering with my compass. When I was getting close to a cache, I was at times directed all over the place. I've removed the magnets now, but haven't had a chance to try it out without them yet.

 

Any other experiences along these lines?

Link to comment
Maybe it is the position of the satellites that is causing different accuracy readings. Maybe is was just chance that when the reception was bad that it was always cloudy. My battery life in cold weather is not very good with the 76S, an external that runs off its own battery really appeals to me. I have found that when I am getting 10-12 feet readings that my ability to find caches goes up considerabely over my ability to find things when it is at 25-30 feet.

Thanks.

Yes, I also suspect it was coincidence that you saw poorer accuracy on cloudy days. Clouds by themselves will not have a noticeable effect. OTOH, wet foliage overhead can reduce the signals and this might be more likely on cloudy days.

 

Since your 76S has a jack for an external antenna you're much better off using that rather than a re-radiating arrangement. The power used by typical external antennas like the Gilsson is only a few mA so the effect on battery life is minimal. If battery life is a concern then carry some spare AA cells - that's easier than carrying the extra electronics and wiring of a re-radiator.

Link to comment

I'm confused about the external antenna. I just received my Gilsson external antenna for my 60CS. I would have thought that one of the benefits of this was the fact that the orientation of the actual GPS unit no longer matters when using the external antenna. That doesn't seem to be the case. With Gilsson plugged in, the 60CS still changes when moved/rotated, just like it does without the antenna. Also, if I rotate the Gilsson, the GPS unit doesn't change at all.

 

Am I missing something?

Link to comment
I'm confused about the external antenna. I just received my Gilsson external antenna for my 60CS. I would have thought that one of the benefits of this was the fact that the orientation of the actual GPS unit no longer matters when using the external antenna. That doesn't seem to be the case. With Gilsson plugged in, the 60CS still changes when moved/rotated, just like it does without the antenna. Also, if I rotate the Gilsson, the GPS unit doesn't change at all.

 

Am I missing something?

 

The 60cs has the magnetic compass. So when you rotate the unit the compass should turn. When you are moving is when the external antenna (Or your built-in) will be used for your heading.

 

Now if you took your antenny and put it on your head, and had a buddy walk with your gps it would not show movement because the antenna is standing still.

 

hope that helps

 

Joe Smith

Link to comment
With Gilsson plugged in, the 60CS still changes when moved/rotated, just like it does without the antenna.  Also, if I rotate the Gilsson, the GPS unit doesn't change at all.

Are you sure it's fully plugged into the antenna jack? If so you may have some defect - either in the antenna or the jack on the 60cs.

 

Try covering the antennas with either your hand or a piece of aluminum foil. When my Gilsson is connected to my eMap the signals will go away completely if I wrap my hand around the Gilsson antenna and there's no effect if I wrap my hand around the top of the eMap.

 

But if you're talking about the compass pointer rotating, then Joe's response is correct

that this would be based on the magnetic compass sensor and is independent of the GPS antenna.

Edited by peter
Link to comment

OK, I just did the foil test. Thanks for the suggestion. I definately lose signal quickly when the foil is covering the Gilsson, but no ill affects if I cover the internal antenna while the Gilsson is attached. Also, if I unplug the Gilsson and cover the internal antenna with foil, the signals go away. That, I beleive, proves that the Gilsson is doing something at least.

 

That being said, I'm still confused as to why the map screeen would move orientation if moved/turned while the Gilsson is plugged in. I'm doing this test from a "standing-still" position. One last question, how should the Gilsson be positioned when mounted to the windshield? Should it be straight up and and down (vertically) with the cord side being at the bottom?

Link to comment
That being said, I'm still confused as to why the map screeen would move orientation if moved/turned while the Gilsson is plugged in. I'm doing this test from a "standing-still" position. One last question, how should the Gilsson be positioned when mounted to the windshield? Should it be straight up and and down (vertically) with the cord side being at the bottom?

As Joe indicated earlier, the 60cs determines orientation when standing still (or moving slowly) by using an internal magnetic compass sensor (prob. fluxgate). So if you have the map screen set to show 'Track Up' it will rotate to show the direction the unit is facing, regardless of any antenna.

 

The Gilsson should be mounted flat for best reception. I just put it on top of the roof when driving so it gets the best skyview. The cable is thin enough that I can just close the door on it and it's cushioned by the weatherstrip gasket between the door and car body.

Link to comment

If you are finding that battery life is an issue in very cold weather then I'd suggest you try Lithium batteries. Cost a lot more but they last so much longer and remain unaffected by the cold. To save money switch between standards and Lithiums depending on the temp. Oh and make sure you keep the alkaline batteries warm when possible as they lose performace very quickly in the cold.

Link to comment
Based on what you said, it doesn't sound like there's any benefit in using the Gilsson in any "out-of-car" mode, like walking around, etc.

I certainly didn't mean to give that impression. I find it very useful in improving GPS reception at times when walking through areas with poor reception due to dense foliage. Your 60cs can determine orientation using the magnetic sensor, but it still needs good GPS reception to determine your position. Under marginal conditions the external antenna can make a big difference in getting that extra satellite or two that are needed for a more accurate position measurement (or even to get a lock at all).

Link to comment

I wrapped a thin metal strap around the shoulder strap of my backpack. I set the antenna on it, put the excess cord in my pack, and clip my GPSr to my belt while hiking. The metal is wrapped so that the antenna is sitting on top of my shoulder.

 

Some folks have hats with pockets in them, and put the antenna there. I'm thinking that would look pretty geeky, but then, who cares if you are wondering around in the woods following the arrow on your gadget.

Link to comment
I used my new Glisson external antenna for the first time geocaching with my 60CS yesterday.  It does pull in a much stronger signal -- more satellites and higher bars!  But, I didn't pay attention to how many feet it was down to.

 

I have a cap that has a pocket (keys/change?) in it and I put the antenna in that. I'm sure I looked like a geek, but...  :o

Did you peel off the little bits off of the back and remove the little bar magnets?

 

I found that the magnets were interfering with my compass. When I was getting close to a cache, I was at times directed all over the place. I've removed the magnets now, but haven't had a chance to try it out without them yet.

 

Any other experiences along these lines?

No, I didn't remove the magnet -- I read that you could/should... How close does it have to be to affect it? I was wearing the antenna in the pocket in the cap on my head and holding the GPS.

 

I did manage to find 4 caches yesterday and I didn't notice the compass being affected...

Link to comment

Did you peel off the little bits off of the back and remove the little bar magnets?

 

I found that the magnets were interfering with my compass. When I was getting close to a cache, I was at times directed all over the place. I've removed the magnets now, but haven't had a chance to try it out without them yet.

 

Any other experiences along these lines?

No, I didn't remove the magnet -- I read that you could/should... How close does it have to be to affect it? I was wearing the antenna in the pocket in the cap on my head and holding the GPS.

 

I did manage to find 4 caches yesterday and I didn't notice the compass being affected...

As I understand it, the compass kicks in in helping you get closer to the cache after you slow down or stop moving. Those little magnets are the strong rare earth type I think. As I said, I'll have to see if I notice any difference now that they're off the next time I go out.

Link to comment

Did you ever find out if the magnets affected the 60CS compass? I am imagining the magnets at either shoulder-top or head-top level, and the GPSr near a belt level. (watching the GPS, and walking into more branches!)

 

Is the Gilsson you are using the mcx model with the 90 degree / right angle connector, or the 180 degree straight model? Am curious what folks went with, and why. I am enough of a fool to go for a separate antenna to semi-permanently place on the jeep, will determine the length of run using a string for that. But wanted to know whether the 3' cord was enough for handheld use, or if you went for the 9' and coiled the excess.

 

(the amateur radio appliance operator in me just is not into adapters or excess cable, when I can avoid the line loss . . .)

Link to comment
Did you ever find out if the magnets affected the 60CS compass? I am imagining the magnets at either shoulder-top or head-top level, and the GPSr near a belt level. (watching the GPS, and walking into more branches!)

 

Is the Gilsson you are using the mcx model with the 90 degree / right angle connector, or the 180 degree straight model? Am curious what folks went with, and why. I am enough of a fool to go for a separate antenna to semi-permanently place on the jeep, will determine the length of run using a string for that. But wanted to know whether the 3' cord was enough for handheld use, or if you went for the 9' and coiled the excess.

 

(the amateur radio appliance operator in me just is not into adapters or excess cable, when I can avoid the line loss . . .)

That is the unit that I went with. I choose the 90 degree angled attachment point and the 9' cord. I haven't used it yet on an actual journey, but just standing outside and plugging in the antenna on the 60cs makes a noticable improvement in signal strength.

Link to comment
Did you ever find out if the magnets affected the 60CS compass? I am imagining the magnets at either shoulder-top or head-top level, and the GPSr near a belt level. (watching the GPS, and walking into more branches!)

 

Is the Gilsson you are using the mcx model with the 90 degree / right angle connector, or the 180 degree straight model? Am curious what folks went with, and why. I am enough of a fool to go for a separate antenna to semi-permanently place on the jeep, will determine the length of run using a string for that. But wanted to know whether the 3' cord was enough for handheld use, or if you went for the 9' and coiled the excess.

 

(the amateur radio appliance operator in me just is not into adapters or excess cable, when I can avoid the line loss . . .)

I got the 90° right angle connector with the 9 foot cable. I would polly have gone for a 4 or 5 foot cable if they'd offered it. Three feet seems too short. I wanted to use it both in the car and on the trail.

 

I really recommend the 90° over the 180°, especially if you have a neoprene case. The only shortcoming with the 90° is that I need to use my Leatherman pliers to remove it due to the really snug fit and not much to grab with my fingers.

Link to comment
Did you ever find out if the magnets affected the 60CS compass?  I am imagining the magnets at either shoulder-top or head-top level, and the GPSr near a belt level. (watching the GPS, and walking into more branches!)

 

Is the Gilsson you are using the mcx model with the 90 degree / right angle connector, or the 180 degree straight model?  Am curious what folks went with, and why.  I am enough of a fool to go for a separate antenna to semi-permanently place on the jeep, will determine the length of run using a string for that.  But wanted to know whether the 3' cord was enough for handheld use, or if you went for the 9' and coiled the excess.

 

(the amateur radio appliance operator in me just is not into adapters or excess cable, when I can avoid the line loss . . .)

I read above that these Gilsson antennas can be purchased for around $20. The link for this one shows $49.00. Is there another place to purchase them?

 

Also, I too have noticed a decline in accuracy on cloudy days. High cirrus clouds don’t seem to have an effect but stratus clouds can. Thicker clouds have an even greater impact. Last summer while traveling through Missouri, we drove into a thunderstorm and went from 10 satellites to NOTHING! For about 25 minutes we couldn’t even get a faint reading on a single satellite. I never had any problems after that, even in the mountains of Colorado.

Link to comment

The gpsgeek site used to emphasize direct selling and had the antennas for $19.49. Recently they switched to the dealer distribution model and raised the price on their site so as not to undercut their dealers. I think tvnav sells them for about $25 but his site is currently under construction and hard to navigate.

 

I've been in lots of thunderstorms and other thick cloud layers with my GPS and never noticed a significant reduction in signal strength. So my personal experience confirms the GPS specifications which call it an all-weather system. Is it possible that your windshield was covered with a thin sheet of water at the time you noticed the signal loss?

Link to comment

I think this topic has been done to death, but anyway... :D

 

I have the Garmin GA 27C Low Profile GPS Antenna that I use on my cars with my GPSmap76S and eMap units. This is a magnet mount affair that also has provisions for mouting to your windshield by virtue of its suction cups. The antenna pulls in full-scale signals in any weather. Truth be told, the only time I've lost a signal was when it was under 4 inches of snow on the roof of the car. What's perhaps most useful is the fact that it works well in downtown areas. My only complaint is that the magnet is only just strong enough to hold it to the roof - I'm more used to mag-mount antennas that have to be pried off. :D

 

Cheers!

Coupar-Angus

Link to comment
The gpsgeek site used to emphasize direct selling and had the antennas for $19.49. Recently they switched to the dealer distribution model and raised the price on their site so as not to undercut their dealers. I think tvnav sells them for about $25 but his site is currently under construction and hard to navigate.

 

I've been in lots of thunderstorms and other thick cloud layers with my GPS and never noticed a significant reduction in signal strength. So my personal experience confirms the GPS specifications which call it an all-weather system. Is it possible that your windshield was covered with a thin sheet of water at the time you noticed the signal loss?

Water on the windshield? Yes, there was lots of water, although I've never really noticed much of a problem with rain. This particular storm was a super cell near St. Louis on May 27th or 28th, 2004. There were several tornados and lots of hail associated with this storm. It's the only time I've been on flat ground and not been able to pick up satellites. (I take that back. There is some sort of military Doppler radar east of Peoria, IL, that we pass on our way to the Ingersoll Boy Scout Camp. The highway goes right past the facility but long before you get there, GPS signals disappear. I assume they are jammed?)

 

Thanks for the antenna feedback! I appreciate it.

Link to comment

Clouds don't affect GPS reception, but even a relatively thin film of solid water can block the signals. There is a big difference between water droplets in clouds and solid water. The water on your windshield from a heavy thunderstorm will certainly block the signals, but I regularly fly inside clouds using a GPS for navigation, and I can tell you that the clouds have no effect whatsoever.

Link to comment
Did you ever find out if the magnets affected the 60CS compass? I am imagining the magnets at either shoulder-top or head-top level, and the GPSr near a belt level. (watching the GPS, and walking into more branches!)

 

Is the Gilsson you are using the mcx model with the 90 degree / right angle connector, or the 180 degree straight model? Am curious what folks went with, and why. I am enough of a fool to go for a separate antenna to semi-permanently place on the jeep, will determine the length of run using a string for that. But wanted to know whether the 3' cord was enough for handheld use, or if you went for the 9' and coiled the excess.

 

(the amateur radio appliance operator in me just is not into adapters or excess cable, when I can avoid the line loss . . .)

 

Well, I bought mine for long distance hiking but didn't pay too much attention to the length. I ended up with the 16' one. Rather than worry about hiving the extra in the pack I put it on the roof of the jeep and ran it through the header to the front of the cab. Now I can have the gps in any setup without worring about the sats.

 

When I get a little closer to my big hike I'll pick up another one, but I think the 3 footer.

 

I have the 90 degree, but after taking it in and out a few times it's getting easier. I really don't pull, just clamp my fingers on it and rotate. The shape of the case helps to pry it right out. the twisting motion couldn't hurt.

 

 

It helps if you VERY GENTLY crimp the antenna side of the connection to mave it just slightly smaller. Then it will pop right out. I didn't do it for this one, but did on my satellite radio.

 

 

 

Joe Smith

Link to comment

Anyone thinking about the Gilsson case should know that the antenna plug is still fully accessible on the 60cs without any modifications. You can use the clip or strap feature to attach to any convenient spot and not have a problem with the antenna plug. Work great on/with mine.

Link to comment

I wouldn't think of removing the magnets in my antenna. I put it on the cachemobile roof for driving directions anywhere, and my GPS can go wherever I like, usually in a cupholder close by where I can see it. When I want to walk with it, I put on my hard hat, which makes me look more 'official' if someone sees me walking around, put the antenna on the large steel washer attached to the top, and away I go. The lead runs through a small d-ring on the back of my caching vest (actually a mesh fishing vest from Wally World) to the GPS, which I can carry anywhere without worrying about reception. The hard hat also keeps the briars, thorns, branches, etc off my head when I'm bushwhacking. Back at the cachemobile, it's a quick swap back to the antenna on top of the pickup. The lead goes through the vent window behind my seat. The magnets don't affect my compass at all, the magnetic field isn't that strong, and doesn't extend more than a few inches from the magnets. If you put the antenna within a foot of the compass, you'll see some effects, but that's obvious.

Link to comment
Anyone thinking about the Gilsson case should know that the antenna plug is still fully accessible on the 60cs without any modifications. You can use the clip or strap feature to attach to any convenient spot and not have a problem with the antenna plug. Work great on/with mine.

I second that! The case is very nice. I have a cheapo carabiner on it and a lanyard backup to prevent loss. fie.gif

Link to comment

:blink: I can't find an external antenna for my Magellan Meridian Marine. Does it exist? Support from the website has failed to answer 5 of my questions. And I read all the FAQs and the entire owners manual front to back 3 times. I won't go in to the other questions on this thread.....thanks

 

Joker11

Link to comment
I wonder how good the accuracy is with these re-radiating antennas as opposed to the internal on my unit?

The re-radiating type should work about as well as regular external antennas (but of course with the added size and batteries of the transmitter electronics). In either case the main benefit is that it lets you place the GPS receiver in a convenient location and orientation where that would otherwise result in poor placement of the intenal antenna.

Don't count on the external antenna making a big difference if the internal one is already in a good position.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...