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Antenna For Gps


street1

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I was wondering if anyone uses an external antenna with there gps. Will it help look and lock on better with an external. Please help me because I'm having some problems with locking on and staying locked on.

You should use your GPS for a few weeks without and external antenna, in all the years that I sold GPSrs I always told my customers to use there GPS for a few weeks to make sure they needed on. We sold maybe two antennas a year and those were to customers using them in vehicles like Hummers and some trucks that had windshields that were at about a 90 degree angle.

 

For the most part and external antenna on a hand held GPS while hiking is a waste of money

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You should use your GPS for a few weeks without and external antenna ... For the most part and external antenna on a hand held GPS while hiking is a waste of money.

I have to disagree. I used my eMap for about 5 years and never "needed" an external antenna. But then I happened to be riding past the GPSGeek store so I stopped in and bought their Gilsson antenna for $19. It certainly makes it more convenient now to go hiking and know that I'm getting an excellent tracklog without needing to keep the GPS in a good position. It also helps when travelling on trains and busses which sometimes don't provide good reception unless the antenna is right up against the window - reassuring to check my position on the map when in an unfamiliar city to see when I'm getting close to my stop. And I don't have to be concerned whether a particular rental car may have a metallic coating in the windshield. No, I still don't "need" my external antenna, but I'm glad I have it available and wish I had gotten one earlier. For the cost of about $20, I can't think of anything else that can so greatly improve the convenience and performance of a GPS receiver.

 

BTW, I'm not at all surprised you got few customers coming back to buy an external antenna from you. I wouldn't go back either to the guy who tried to talk me out of buying one; I'd much rather buy from someone who thinks he has a good product that's worth purchasing. You're also in the same metro area as GPSGeek with the $19 price - how much were you charging?

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BTW, I'm not at all surprised you got few customers coming back to buy an external antenna from you. I wouldn't go back either to the guy who tried to talk me out of buying one

 

Well our store policy was to not oversell our customers with cr*p they did not need . As a matter of fact that is why my customers kept comming back because they new I was not going to screw them over. If a customer should ask if I thought they needed an exteranl antenna I would just tell them to try the GPS without it first. Now I have seen employees tell customers that they needed an item that they really did not need, and I have seen those customers come back claiming that they had been riped off. Only some one with no knowledge of the retail industry would think it was a good bussiness practice to take advantage of someone.

 

I have used both Garmin and Magellan GPSr on hikes, while Geocaching and while driving on my dash board and have never needed and external antenna. I have even left them on the pasenger seat while I was driving and even when on that seat they maintained a lock most of the time.

 

I have to disagree. I used my eMap for about 5 years and never "needed" an external antenna.

 

Your words there, you never needed one

 

It certainly makes it more convenient now to go hiking and know that I'm getting an excellent tracklog without needing to keep the GPS in a good position.

 

Were in my post did I day the external antenna would not be more convenient,

What I said was

 

You should use your GPS for a few weeks without and external antenna, in all the years that I sold GPSrs I always told my customers to use there GPS for a few weeks to make sure they needed one.

 

It does not cost anything to try out a GPS for a few weeks before you decide weather or not you need an external antenna. But if someone buys the antenna and later finds out they did not need it, they are no going to be real happy with the person that sold it to them.

 

In the world of retail this is what happens

 

First customer to freinds: I bought this GPS and they told be to try it out for a few weeks before spending money on and exteranl antenna and it works fine, they saved me $20.00

 

Second Customer to freinds : Gee I bought this antenna for $20.00 becausse they said I needed it and I don't. what a bunch of rip offs.

 

Word of mouth in retail can be a retailers best freind or worst enemy, if you new anything about retail you would know that.

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I use one all the time. It fits neatly under my hat and so I don't have to worry about holding the receiver in the proper orientation all the time and I have found that it makes a big difference in reception under tree cover. It's a fact. Under marginal conditions, you can plug the antenna in and see a significant improvement. A friend of mine at work who just started geocaching bought one for his Garmin 60C and he was just amazed at the difference it made while trying to use the receiver indoors. Without it, he could get 2-3 sat's but it would never lock on. He then connected the antenna and within 20 seconds he had lock on 6 sat's. The Gilsson antenna for $20 is a great buy.

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Does the external antenna improve accuracy in a handheld GPSr?

 

If I was standing outside and plugged in an external antenna, would it make a noticeable difference in accuracy? I think most external antennas have a physically larger receiver portion in them as compared to the handheld antenna, and I read somewhere how antenna size might contribute to accuracy.. And I mean holding the external antenna at the same position the builtin antenna was used, not "held high over my head" or something else that would artificially also help with accuracy.

 

Just curious :rolleyes:

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It does not cost anything to try out a GPS for a few weeks before you decide weather or not you need an external antenna.

The way to find out if an external antenna is a worthwhile purchase is to use the GPS both with one and without one and see how much difference it makes. That'll tell you more in a few minutes than will a few weeks of using the GPS with only the internal antenna.

 

What I've seen in previous discussions on external antennas is that almost everyone who has one is happy with it, but JV still always insists that they're a waste of money.

Since the original poster indicated that he's not happy with his reception, I'd recommend he give an external antenna like the Gilsson a try. They don't cost very much and frequently make a big difference.

 

To IVxIV,

Under decent reception conditions I don't think you'd see improved accuracy just by substituting the external antenna unless it allows you to receive additional satellites that would otherwise be blocked by parts of your body or other obstructions. In fact you might see a decrease if the extra gain of a typical external antenna lets it pick up a weak reflected (and therefore delayed) signal from a satellite whose direct signal can't be received.

But in practice the internal antenna in my GPS is frequently blocked from much of the sky by parts of my body and therefore the external antenna can provide an improvement due to better satellite geometry with signals from more directions.

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but JV still always insists that they're a waste of money
.

Well, maybe that is because they are for the most part.. of course I only sold GPSr sense the first consumer one were on the market. But I guess in your mind experience does not mean anything.

 

But in practice the internal antenna in my GPS is frequently blocked from much of the sky by parts of my body

Well, if you hold your GPS just a little further away from your body it will not be a problem, Besides, the only Seattleites your body is going to blocked are going to very low in the horizon unless you are hold the GPS right up against your chest. a lot of the argument I see about someone’s body blocking a GPS signal go back to the days of the old two channel GPSr that had real reception problems. It have not seen a real problem with my body position being a problem.

lets face, you are not going to be looking at your GPS screen the entire time you are hiking to a cache and any accuracy change even just a few hundred feet away does not in all reality is not going to make the difference in finding or not finding a cache.

 

The way to find out if an external antenna is a worthwhile purchase is to use the GPS both with one and without one and see how much difference it makes. That'll tell you more in a few minutes than will a few weeks of using the GPS with only the internal antenna.

 

Not true, you cannot do and accurate study on GPS reception in just a few minutes, you would have to try various areas and types of terrain to do an accurate study.

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I was wondering if anyone uses an external antenna with there gps.  Will it help look and lock on better with an external.  Please help me because I'm having some problems with locking on and staying locked on.

Can you be more specific

How much time are you allowing for the GPS to lock on?

Were are you when you are having the problem?

What type of GPS do you have?

 

Your problem may not be antenna related

Edited by JohnnyVegas
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bought a Gilsson for my Garmin V, I was getting 8 sats and if I waited long enough I would get WAAS, bought the Gilsson, hooked it up in car, antenna on the roof, within 20 seconds I had 11 sats with 3D Differential. average error is now 7 feet with WAAS whereas before it was 17 feet without.

 

for $25.00 inc shipping how can you go wrong?

 

and with a little crazy glue, a steel washer, and my geocaching pith helmet, it is quite nice for rolling around looking for caches (I couldn't figure a place on my wheelchair to mount the antenna), low profile? well, everyone around here thinks I'm the one directing the Black Helicopters anyways, so being able to point to my "Sat Reciever" just gets grins.

Edited by CaptainQuack
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I don't use an external antenna while using my 3+ outside of my vehicle. I get fine reception without it.

 

While in the Jeep, however, I use one. In my WJ, I keep my 3+ on the little shelf created by the open ashtray. A sticky pad keeps it rock steady. Unfortunately, this placement puts the unit too low on the dash to allow it to get very good reception.

 

The solution was to add a powered remote antenna. In fact, on the WJ, you can route the cable into the ashtray, under the dash and onto the little shelf used by the Jeep's own nav unit.

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My Jeep Yj has a fiberglass hardtop, and I find the signal makes it through that no problem :rolleyes:

 

And when snowmobiling, I stick the GPS into an inside coat pocket, and get good signal. After a trail ride I can check the trail plot it left & has great detail. That's one favorite feature of Lowrance iFinder,, 10000 plot points per trail :blink:

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My Jeep Yj has a fiberglass hardtop, and I find the signal makes it through that no problem ...

I guess I failed to say that if I left the original antenna on the unit, it would be folded behind it. Leaving it with an awesome view of the inside of my nice, clean ashtray; but no view of the sky.

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QUOTE 

but JV still always insists that they're a waste of money

 

.

Well, maybe that is because they are for the most part.. of course I only sold GPSr sense the first consumer one were on the market. But I guess in your mind experience does not mean anything.

 

Ouch! Someone throw the penalty flag, that was harsh. I don't think repeating someone's opinion requires a comment back like that.

 

I love, not like, love my external antenna. Do I need it? No. But since I see the GPS better when I can hold it a foot away from my face when I'm driving, not laying up sideways on the dash, I don't risk losing even a bit of signal strength. Even when I purchase a holder, I'll still use the external antenna. I have yet to walk with it while caching, but I intend to. For driving, the flexibility of being able to move the GPS away from the window ("Hey dad, can I see where we are?" asked the lad in the back seat. "Sure son, have a look!")

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It looks like ifinder has a phony hookup for the external.

I don't understand.. according from the Lowrance website...

 

" Precision 12-parallel channel GPS+WAAS receiver

Antenna port for connecting optional external GPS+WAAS antenna"

 

I have the iFinder Pro, and while I've never tried using an external antenna on it,, I do see the little connector at the top of the back of the unit. You think this connector is phony?

 

And not to nitpick but,, I don't think the external antenna option was planned to be used while walking with the unit. Commonly the external antenna is used to optimize reception while being used inside the cab of a vehicle be it a car, boat, airplane, etc

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I'm very new to gpsing and you might think I'm stupid put I really don't no what I should have set on my gps. gll, rmc, apb, gga orgsa and gsv. Also you have coordinate of utm, degrees, degrees/minutes. mgrs standard and mgrs std+10. Can anyone help me to get the best and common settings. sorry for the dump questions.

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It looks like ifinder has a phony hookup for the external. I have the ifinder hunt and it seems that it would be not that good of connection when out hiking.

Not sure why you say that or think the hookup on the iFinder Hunt is "phony."

 

Note that the Gilsson MCX antenna is listed as being compatible with the iFinder H2O here:

http://shop.store.yahoo.com/gilsson/antennas.html and since the iFinder Hunt takes exactly the same Lowrance external antennas I'd expect the Gilsson to be compatible with that model as well. On my eMap the MCX plug makes a very solid connection and I frequently use it while hiking. It lets me keep the unit safely tucked away inside a pants pocket while still getting a good signal and tracklog with the external antenna. Haven't tried it with an iFinder but see no reason why it wouldn't work equally well for that model.

 

On your latest question, GLL, GGA, RMC, GSV, etc. are all sentences in the NMEA standard for transferring data between different marine electronic devices. Unless you're using the NMEA RS232 port output to drive either some software on your PC or something like a chartplotter/autopilot/radar/etc you don't have to worry about those settings at all.

UTM and lat/long are two different ways of defining coordinates of positions on the surface of the earth. For geocaching the most commonly used is latitude/longitude, and in particular using the format of degrees, minutes, and decimal minutes (frequently designated HDDD MM.mmm). I believe that's the default setting on your iFinder anyway so you shouldn't need to change anything.

MGRS is another flavor of the UTM coordinate system and is commonly used in the military. Not used for geocaching, so you can ignore it for now.

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BTW, I'm not at all surprised you got few customers coming back to buy an external antenna from you. I wouldn't go back either to the guy who tried to talk me out of buying one; I'd much rather buy from someone who thinks he has a good product that's worth purchasing.

 

Well thats kind of dumb. Id rather have a good and HONEST salesman than one with a big head about his product.I think this world needs allot more HONEST salesman's.

 

I would listen to him if I were you. He seems to know what hes talking about and another thing is hes HONEST.

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Peter thanks so much for the help. On my ifinder all the gll and ect. are x in the box and really never tells if they should be. Will it hurt to leave them x in the box. Now I think I understand that I should have it on utm is that correct. I wll be using my gps mostly for hiking and hunting. Again thanks for your time.

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I would listen to him if I were you. He seems to know what hes talking about and another thing is hes HONEST.

Why? In this case I've been using the product for about a year and have found it to be very valuable and worth far more than the $19 I paid in increased convenience and performance. So based on my experience with it, as well as similar descriptions by many other posters here (see Poindexter, sbell111, teepeeayy, CaptQuack, and Sputnik57 above as well as others in previous threads), I already know that external antennas can be worthwhile. JV may (or may not) be honest, but I know for sure that he's wrong at least as far as the uses I and the other posters find for our external antennas.

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On my ifinder all the gll and ect. are x in the box and really never tells if they should be. Will it hurt to leave them x in the box. Now I think I understand that I should have it on utm is that correct. I wll be using my gps mostly for hiking and hunting.

Leaving the various NMEA sentences (GLL, etc.) checked shouldn't hurt - just a few extra bits appearing on the serial port. That way they'll be available if you ever do have a need to hook your iFinder up to something that needs to see that NMEA data.

 

For geocaching latitude&longitude is used more commonly than UTM although both are shown on the website pages. But for some multi-caches and other situations where you need to enter new waypoint locations it's much more likely that the latitude and longitude will be provided. So I'd suggest using lat/long rather than UTM while geocaching.

 

For hunting and hiking the preference would depend on any paper maps that you may be using for navigation. If those are marked in UTM then set the iFinder to be consistent. Here's a brief description of UTM (Universal Tranverse Mercator):

http://gpsinformation.net/main/utm-faq.html

 

The other setting you may run into is the datum, which refers to the model of the shape of the earth used when generating a map. For geocaching and most GPS-based maps the WGS-84 datum is used and that's the default on your iFinder. But for accurate plotting of waypoints on maps created with a different datum you may need to sometimes set your iFinder to that datum. The map generally gives the datum somewhere in the legend area. Many of the USGS topo maps use the NAD27 datum.

But again - leave it at WGS-84 unless you have a specific need to change it.

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JV may (or may not) be honest, but I know for sure that he's wrong at least as far as the uses I and the other posters find for our external antennas.

 

No you are wrong, an external antenna is not need for geocaching, you may chose to think you need one, that is you viewpoint. You are welcome to live on your little world of fantasy all you want.

I know lots of geocachers, and have been geocaching with some of the best and I have never seen any of them use and external antenna. Even at $19.00 if you do not need it it's a waste of money.

 

Edit to add:

 

Captain quack

Error is now 7 feet wheras before it was 17 feet without

Gee, 90% of the time My Meridian Gold always gets me withing around 5-15 feet of a cache with it's bulit in antenna, no big improvement here.

Sbell111

I don't use an external antenna while using my 3+ outside of my vehicle. I get fine reception without it.

Sounds like it's not needed to me

 

Teepeeavv

I love, not like, love my external antenna. Do I need it? No.

Sounds like it's not needed to me

 

Could it be Peter has a selective memory of what others have posted

 

Lets not forget peters own words

I have to disagree. I used my eMap for about 5 years and never "needed" an external antenna.

What can I say, Peter said it is not needed himself

Then again with Peters perception of how the retail world works my guess he has never been there or if he was he may not have been very Honest with his customers.

 

By the way Need and Convenience are not the same

 

Definitions

 

need

n.

A condition or situation in which something is required or wanted: crops in need of water; a need for affection.

Something required or wanted; a requisite: “Those of us who led the charge for these women's issues... shared a common vision in the needs of women” (Olympia Snowe).

Necessity; obligation: There is no need for you to go.

A condition of poverty or misfortune: The family is in dire need.

 

v. need·ed, need·ing, needs

v. aux.

To be under the necessity of or the obligation to: They need not come.

 

v. tr.

To have need of; require: The family needs money.

 

v. intr.

To be in need or want.

To be necessary.

 

 

Convenience

con·ven·ience (kn-vnyns)

n.

The quality of being suitable to one's comfort, purposes, or needs: the convenience of living near shops, schools, and libraries.

Personal comfort or advantage: services that promote the customer's convenience.

Something that increases comfort or saves work: household conveniences such as a washing machine, an electric can opener, and disposable diapers.

A suitable or agreeable time: Fill out the form at your earliest convenience.

Chiefly British. A lavatory.

Edited by JohnnyVegas
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BTW, I'm not at all surprised you got few customers coming back to buy an external antenna from you. I wouldn't go back either to the guy who tried to talk me out of buying one; I'd much rather buy from someone who thinks he has a good product that's worth purchasing.

 

Well thats kind of dumb. Id rather have a good and HONEST salesman than one with a big head about his product.I think this world needs allot more HONEST salesman's.

 

I would listen to him if I were you. He seems to know what hes talking about and another thing is hes HONEST.

Thank you Stony

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Peter, thanks for your help and I really apppreciate for explaining some of the things I ask for. I did print our reply's and put in my book so I have that info. I guess with my gps I thought I would get better signal. It takes a 15m to lock on and then when I start moving it goes on and off. Do you always have to have thr gps in your hand. I hear people put them in there pockets and go. With mine if I put it in a coat pocket with the top sticking out I lose lock on. Thanks again man.

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The OP never asked if he "needed" an external antenna. He just wanted to know if it would help with locking on and staying locked on to the signals. The answer is of course, yes, under certain conditions. JV, you are the only one hung up on this issue of need. Do you need your GPSr to Geocache? No, some people geocache without one at all. Do I need my $400 Garmin unit? No, I could get by with a cheap Gecko model. Do I need my external antenna? No, but it sure is convenient and helps with reception under tree cover. As far as fantasy, to say that your GPSr always gets you within 5-15 feet 90% of the time, well that's fantasy! :D

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...In this case I've been using the product for about a year and have found it to be very valuable and worth far more than the $19 I paid in increased convenience and performance. So based on my experience with it, as well as similar descriptions by many other posters here (see ..., sbell111, ...), I already know that external antennas can be worthwhile. JV may (or may not) be honest, but I know for sure that he's wrong at least as far as the uses I and the other posters find for our external antennas.

After reading this thread through, I realize that people may be discussing more than one use for an external antenna.

 

Personally, I really love mine. It allows me to mount my 3+ in my WJ in a really good way. It looks (almost) professionally installed and is out of clear view to help keep my vehicle from getting broken into. It should be remembered, however, that these external antennas are powered by the GPSr. This severely limits your battery life. This isn't a problem in the Jeep because my 3+ is on external power. On trail, however, I'd rather not have to keep changing batteries.

 

As I posted before, my 3+ gets good reception on trail. I personally would find the corded, external antenna to be irritating while hiking. Combine this with the fact that I don't need better reception and I get better battery life without it and the answer is simple. My external antenna stays in the Jeep.

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To get back to the original question...

 

I don't believe that an external antenna is necessary to play this game.

 

It can be a convenience in your vehicle when your GPSr is hooked into external power. In my opinion, however, the negatives outweigh the positives for use outside of your vehicle.

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I have a RAM windshield mount to hold my 60C in my Jeep TJ. Even though the windshield is nearly verticle, I get good receiption through the rag top. Hiking in the woods, my signal is pretty good, so long as I hold my GPS with its quad helix antenna pointing up. When I put the GPSr in my pocket or clip it to my belt in the woods, I sometimes lose signal

 

I have a Gilsson external, that I stick to a metal strap on the shoulder strap of my backpack. With the Gilsson attached, I don't need to hang on to my GPSr while I hike. I can clip it to my pack or belt and never loose signal. It is really nice on a long days' hike. I haven't noticed a major difference in battery drain. I can cache all day on a set of NiMH rechargables, with or without the antenna. I think that the Gilsson was $19 well spent.

 

So for me, my car reception is fine, but I like the external when I hike. I think it boils down to your personal circumstances and preferences.

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It should be remembered, however, that these external antennas are powered by the GPSr. This severely limits your battery life. This isn't a problem in the Jeep because my 3+ is on external power. On trail, however, I'd rather not have to keep changing batteries.

 

These antenna's typically draw less than 10ma of current. In fact, the Gilsson is rated at 7ma. Compared to the 125ma that my Map76 uses, that is very little and certainly isn't a severe load.

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It takes a 15m to lock on and then when I start moving it goes on and off. Do you always have to have thr gps in your hand. I hear people put them in there pockets and go. With mine if I put it in a coat pocket with the top sticking out I lose lock on.

15 minutes sounds way too long to get a lock if you're standing in an area that has a reasonable skyview. This should be under a minute unless you've moved hundreds of miles from the last time you used the unit or it's been sitting idle for months (and therefore has an invalid almanac). It's best to avoid moving until the unit gets a lock.

 

The internal antenna on the iFinder models is a metal patch located in the top part of the case. For best reception, the unit should be held close to horizontal with the top of the case away from your body. When it's in your pocket the unit is nearly vertical and close to your body so the signals will be largely blocked.

Some other models (like the Meridians and 60/76 series) have antennas that work best when vertical and these can work better when in a pocket with just the top sticking out; but OTOH, they don't work as well as possible when lying flat on a table whereas that's an excellent position for the iFinder.

 

If you don't want to hold the unit while hiking, there are various ways to attach it so the internal antenna still gets a good signal. Radio Shack makes an armband with a small pocket for their FRS radios which is also a good size for the iFinders and can hold it near the top of your arm facing out. Cases that attach to shoulder straps also work well, as does placing the unit flat inside a fannypack and facing up. And of course as mentioned before, I find the external Gilsson antenna a good way to keep a good signal while hiking and not have to worry at all about where I put the GPS receiver or its orientation.

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There is at least one case that I can think of when an external antenna would be a great help. I rent a lot of cars in my work and have discovered that certain Pontiacs and Buicks have some kind of coating on their windshields (maybe to keep out the heat) which blocks the signal. It makes navigating with my 60CS almost impossible. (Can you see me holding my GPS out the side window to get a signal). If I had an external antenna it would solve this problem. Now for the rest of us. I have never used and external antenna and have not had any problems except as stated above and I have a current cache find count of 778. Must be doind something right. :unsure:

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Yeah I that metallic film on some cars windsheilds is an electronic defroster of sorts.. It works faster than the heater/blower found in most cars. And yup it can restrict GPSr signals, and also can block radar detectors from working too, so WATCH OUT :unsure:

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well, I don't NEED an powered external antenna, and I don't NEED a GPSr, and I don't NEED a car, and I don't NEED my legs. but I am quite enjoying having them all anyways.

 

and yes, they do help. but do you need one? no.

 

(and it also lets my wife hold it in front of her so she can see it as opposed to having to try and read tiny print half way across the dash with variable lighting and glare)

Edited by CaptainQuack
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WHERE you are using the GPS makes a difference, too. If you're under heavy tree cover, an external antenna may make the difference btwn getting a signal lock and losing it.

 

I don't always need an external antenna, but sometimes I DO need one. So if you're having problem getting a signal lock then the $20 Gilsson may solve the problem for you, while at the same time giving you a lot of options in how you carry your GPS.

 

I don't doubt what JohnnyVegas has seen, but I don't doubt my own experiences, either. So obviously, the equipment and environment makes a difference. If he spent a lot of time in the forests of British Columbia perhaps he would change his mind? And if I spent time in Nevada, perhaps I would see that an external antenna isn't needed there.

 

GeoBC

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Man O' man some one is honest and you beat him up for it. JV sounds like the knid fo sailsman I would like to deal with. Peter sees like the kidn of person that wants every toy out there. Thought Peter has twiked my interest in his GPSr antenna not sure if I would run out and buy it as so far I have no need.

I hope we can all learn to play together nicely now. Sorry if I stepped on any toes but just maiing a few observation. I bet JV will teach you to use your GPSr if you come into his shop. I went to one store and they wanted $20.00 for a class, guess where I haven't gone back to.

 

cheers

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Before I retired I was giving GPS seminars from the early days of GPS, years before geocaching, when geocaching started getting popular we gave geocaching seminars in a locale park, some of these seminars drew as many as 50 people.

And we did not charge for them, it was considered customer service.

 

Early GPSr had problems with maintaining locks but the technology has change. What held true 10 years ago does not hold true now. Early GPSr only operated on two channels. they would lock onto two satellites, then break off from them and find two more, then when they found two more they would break off from them and look for two more. With these old units when you turn them it can take 30 minutes just to get a lock. another problem they had was that the receivers were so bad that they could not maintain a lock through a wet wind shield because of the extra layer on water on the glass, that is one reason the OLD GPSrs need external antennas while driving. New recovers are much more sensitive eliminating the need for and external antenna except for in a few very limited situations.

 

As far as the antenna issue, if your are looking for a cache in an area in which and you cannot get a lock, there is a very good chance you are in the place anyway. A person needs to be locked onto the satellite to hide a cache and sense very few cachers use external antennas the external antenna just is not going to be very useful, the odds are the person did not have one so why would anyone need one to find a cache, They do not need one.

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As far as the antenna issue, if your are looking for a cache in an area in which and you cannot get a lock, there is a very good chance you are in the place anyway. A person needs to be locked onto the satellite to hide a cache and sense very few cachers use external antennas the external antenna just is not going to be very useful, the odds are the person did not have one so why would anyone need one to find a cache, They do not need one.

You forget about all the hundreds of caches being hidden during the late fall, winter and early spring in much of the country while there are no leaves on the trees. The external antenna will be a plus when searching for these caches in the summer under dense foilage.

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Peter sees like the kidn of person that wants every toy out there.

LOL! First time I've *ever* been accused of that. The fact that I'm still using the same eMap I got while Selective Availability was active might be considered an indication to the contrary - and it's one of my newest acquisitions.

 

The eMap works very well with just its internal antenna. In fact at the moment it's sitting on my desk far from windows and with rain falling on the roof and it has a lock on 6 satellites. But there's still room for improvement and I've found that overall it works significantly better with an external antenna - particularly in situations where the external can be located in a less obstructed spot. In a car I get fewer loss-of-lock situations in tight urban or natural canyons and when hiking I can keep the receiver in a pants pocket or other convenient place and still record a good uninterrupted tracklog.

 

But if I had followed JV's advice I never would have even tried using the external. Afterall, the eMap worked 'well enough' without it. Five years of using it without the extra antenna didn't tell me anything about how much of an improvement I could get by adding one. But a few minutes spent near the GPSGeek store in a few spots between buildings where reception was spotty let me do A/B comparisons which showed both the benefits and limitations of the external antenna and convinced me that it would be a worthwhile purchase - which it was.

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Peter sees like the kidn of person that wants every toy out there.

LOL! First time I've *ever* been accused of that. The fact that I'm still using the same eMap I got while Selective Availability was active might be considered an indication to the contrary - and it's one of my newest acquisitions.

 

The eMap works very well with just its internal antenna. In fact at the moment it's sitting on my desk far from windows and with rain falling on the roof and it has a lock on 6 satellites. But there's still room for improvement and I've found that overall it works significantly better with an external antenna - particularly in situations where the external can be located in a less obstructed spot. In a car I get fewer loss-of-lock situations in tight urban or natural canyons and when hiking I can keep the receiver in a pants pocket or other convenient place and still record a good uninterrupted tracklog.

 

But if I had followed JV's advice I never would have even tried using the external. Afterall, the eMap worked 'well enough' without it. Five years of using it without the extra antenna didn't tell me anything about how much of an improvement I could get by adding one. But a few minutes spent near the GPSGeek store in a few spots between buildings where reception was spotty let me do A/B comparisons which showed both the benefits and limitations of the external antenna and convinced me that it would be a worthwhile purchase - which it was.

 

 

Well for your information the e-map has a 12 channel reciever, from Garmins web site.

 

Here's another reason to toss out those paper maps: the eMap. It's the size of a small, flat calculator, contains a 12 parallel channel GPS receiver, and weighs a mere six ounces

 

Then again the improved reception you see with the external antenna could be because the E-map has a patch antenna

Here is a link to the Garmin e-map page. BTW the E-map was a real dog as far as sale went, partilly becuse to the chip required being a Garmin chip and also becasue it had not waterproof rating, the reps alway reminded that it should no be used as a marine GPS.

 

E-map

 

Selective Availability has nothing to do with the age of your GPS, when Selective Availability was turned off all GPSr that were in use saw the benifit.

 

Before Selective Availability was turned off the accuray would have been about 100 meters.

 

As far as poindexters comment

 

You forget about all the hundreds of caches being hidden during the late fall, winter and early spring in much of the country while there are no leaves on the trees. The external antenna will be a plus when searching for these caches in the summer under dense foilage.

 

Not all trees lose their leaves and I have never seen any scientific study to back up this claim that GPSr lose reception because of leaves in trees. Can you provide a link to any study that has been done to prove this claim.

There were issue with older GPSr, but I have never heard of the tree leaf problem with a 12 channel.

 

Again, what was true in the early days of GPS technology is not true today with the newer recievers.

Edited by JohnnyVegas
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Well for your information the e-map has a 12 channel reciever, from Garmins web site.

...

Then again the improved reception you see with the external antenna could be because the E-map has a patch antenna

I'm very familiar with the technical specifications of the eMap and certainly never indicated anything to the contrary.

 

As to the reception capability, I did do some direct comparisons to both the Meridian Gold and Platinum models when those came out. Under poor reception conditions they all came out very similar. The eMap would get a lock only when horizontal and the Meridians would only get one when vertical as expected. When watching the satellite pages it was clear that they were all switching between a 2D and 3D lock in a similar way, i.e. pretty good lock on 3 satellites and a marginal lock on one or two others that would sometimes be lost.

Of course the external antenna is also a patch design and really doesn't perform very different from the eMap's own antenna if held in exactly the same place. The benefit of the external antenna comes mainly from the better placement - on the roof of the car when driving and up high to avoid obstruction from my body and/or lower lying foliage when cycling or hiking.

 

BTW, your description earlier of the older receiver designs was an overgeneralization. Some of the early Magellans had two channel receivers, but the Garmins from that period (like the 90, 40, 45, 38) were all single channel designs that mulitplexed to sequentially receive signals from up to 8 satellites. Eagle had a fairly early model with multiple parallel channels (I believe 5)

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Not all trees lose their leaves and I have never seen any scientific study to back up this claim that GPSr lose reception because of leaves in trees. Can you provide a link to any study that has been done to prove this claim.

There were issue with older GPSr, but I have never heard of the tree leaf problem with a 12 channel.

 

While you may be a good salesman, you clearly have little understanding of the technical aspects of the GPS. My experience is 29 years as a Marine Electronics Technician having repaired/maintained/installed many types of GPS receivers since the first marine units came out and the Navy's Transit Satellite system receivers before that. But you can't be swayed as your one of those guys whos receiver ALWAYS gets you within 5-15 feet of a cache and your receiver ALWAYS maintains good satellite lock no matter what. Probably even works in the trunk.

 

http://www.fs.fed.us/database/gps/mtdc/map...smap_76_rev.pdf

http://www.waypnt.com/html/hgg24.html

http://www.fs.fed.us/database/gps/mtdc/gps.../Nav_3-2001.htm

http://www.digitalgrove.net/bolstad_gps_comparisons.htm

http://www.digitalgrove.net/GPS.htm#external

http://www.delorme.com/support/postpro/GPS...ion_Methods.pdf

http://www.gpstom.de/GPS/gar-wood.htm

 

Even Garmin states that tree cover can block GPS signals.

 

And you don't need a scientific study to prove the difference. Just walk into the forest, take note of the number of sat's you are receiving and their signal strength and then plug in the external antenna and watch the signal strengths rise and the number of sat's increase.

Edited by Poindexter
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BTW, your description earlier of the older receiver designs was an overgeneralization. Some of the early Magellans had two channel receivers, but the Garmins from that period (like the 90, 40, 45, 38) were all single channel designs that mulitplexed to sequentially receive signals from up to 8 satellites. Eagle had a fairly early model with multiple parallel channels (I believe 5)

 

Which is why none of the earlier recievers from Magellan, Garmin, Eagle/Lowrance (Lowrance and Eagle are the same Company) perform as well and the 12 channel models we have now.

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