Has anyone used an external antenna?

I have not had a need for an external antenna. Most current GPS receivers are quite sensitive with the existing OEM antenna.

...used an external. The slight improvement, IMHO, is not worth the cost. If the antenna is not mounted permanently, it's certainly not worth the hassle of connecting and disconnecting.

I have an external antenna, and I don't use it very often. It does provide stronger signals, but in practice signal strength hasn't been a problem. It also allows you to mount the GPSr someplace without a direct view of the sky.

If you have a good antenna - GTM 25 or GTM 35 and not getting good reception its probably because you are not in range of the FM transmitting station signals. I am in northern NJ and having on and off reception. its disappointing I just want to turn the traffic function off.

don't think it has anything to do with GPS reception though.

I used a Garmin GPS V from shortly after they came out for about 10 years. When it was still pretty new I bought the external antenna and tried it out a few times. (this was not really an external antenna, but rather a cable and suction cup with which to remotely attach the existing antenna) The receiver on that model was enough less sensitive than on current models that getting reception on commercial airliners was a matter of holding it very close to the window. The external antenna came with a suction cup and the idea was that I could stick it to the window and have good reception without having to hold the receiver in my hand. The antenna worked well enough for that purpose but the suction cup did not.

So the truth is that I never used the external antenna after the first few trials. I still do believe that it would have been useful one other way. I think when hiking in moderate to low density forest, I could have mounted the external antenna so that it would have an unobstructed view of the sky in all directions by placing it on a stick in my backpack elevated just above my head. With the somewhat less sensitive receiver of that model it lost lock in very light forest canopy, and I think that by avoiding the sky blocking of my body in some directions that use of the external antenna would have given improvement. But since I hardly ever hiked in those days, and I never tried it.

I have a 765t in my truck, it is mounted on a stand in the console. At times, and certain places I lose the signal and have to reboot the Garmin, usually by a window to get it back on the signal. Bought an external ant from Ebay for just under $10.00 no problems since.

I don't see the use for it unless you in the city with a lot of skyscraper.

I used one with an older GPS and it woked really well. When I got a newer unit and I had no need for an external antenna as they both work great on a bean bag mount from the center console or window.

Great feedback. based on the majority of comments, I'll likely take a pass on buying on since my unit is only 2 years old.

I have used one on my 755w and if in a poor reception area it really helped. In most areas its not needed. My advice is if you are consatantly in poor reception areas or if you are in a situation where you can't risk losing the signal (on the way to a business meeting and can't be late) then get the antenna or have a backup plan (maps anybody)

-- on both my 680 and my trimble gear.

An external antenna on a vehicle will give you a much better view of the sky. If you're not driving around in "urban canyon" situations where large buildings are occluding patches of sky, it may not matter. But in situations where you need every bird you can see, an external antenna, one not partially shielded by the metal roof on the car, can help.

(Another place where external antennas are useful -- my trimble receivers don't have antennas built into them, so an external antenna is the only way to go.)

If you're running multiple receivers, you probably know about the HP and Symmetricom GPS antenna splitters. These show up on eBay from time to time and let you drive 2 (or 4) GPS receivers off a common antenna.

I use an external antenna for occasions where I am tracking my trip. I use it on Amtrak and flights on planes. On these two occasions there is very limited sky available. Especially if you have an isle seat and are not next to the window. I find the gain from the external antenna makes a lot difference. And I don't have to worry about signal dropouts and losing tracking.

I have tried several times, but did not notice any improvement in reception.

Learned quite a bit from this discussion.

In doing a quick search, one review on Amazon stated that leaving the antenna connected to the unit had drained the battery in the vehicle. Not sure if others have experienced that or not, but it may be something to keep an eye on. Amazon item in question is: http://www.amazon.com/Powerful-External-Amplified-Antenna-Re...

I'm still trying to figure out whether the OP mean an external GPS antenna, or an external traffic antenna...

Guess I'm kinda slow this morning.

when in larger cities where tall buildings may interfere with direct view of sky. Some are magnetic mount so they can be placed on top of car or a windshield mount and removed when you park.
I bought one with my first gps but have never used it with my 765T.

I use an external with my laptop and Delorme software, when a PND can't give me the data I want to manipulate or see on the screen.
Do they help Garmin PND's, sure they do. However the average user here on the factory wouldn't realize that.

Any type of canyon formed by Geology or man made and then canopies of any sort, these are areas where GPS signals are attenuated, screened or blocked.

For those that say externals make no difference.

Example:
The Amplified Gillson GA 25MCX will give you 28 db gain, and satellite locks that are crazy fast. External antennas will find signal where you usually can't find any and remain locked.

Product Specifications

Radome: Black Polycarbonate Radome with die-cast base
Dimensions: 2.3 in. (L) x 1.9 in. (W) x 0.6 in. (H)

• Mounting (included): Two permanent magnets;two M3 screws for holes on base.

• Power Gain: 28 dB Gain.
• Operating Voltage: 2.5V~12V DC Power.
• Power Consumption: 12mA +/- 1mA.
• Operating Temperature: -40 to +185 degrees F.
• Noise: 2.0 max.
• Impedance: 50 ohm.
• Frequency: 1575.42 MHz.
• Cable: RG174/U.

others comments. Back in the days of eMaps and GPS-38s and the like, externals were almost a must.

I've used, and still own several externals, including an NMO mount GPS antenna on my van.

Even with my now aging but trusty, C330, I find no need for an external antenna,even in my Freightliner Semi.

No.. but I've been thinking about it. I mean for 10 bucks. It's only $10.

Nuvi1300WTGPS

My old 350 saw a small improvement, but when the internal antenna quit on my 300, it saved my butt.

I used one on my Street Pilot 2610 when the built in one did not work (in house and in car away from window).

It worked fine - no problems.

Not to advertise or reccomend antenna products but this is what I use, I think it works very well
Under $10.00
http://www.ebay.com/itm/220826580084?ssPageName=STRK:MEWNX:I...

I have my 760 mounted down low in the car - on the center console right in front of the dash. I get poor reception in that location, so I added an external antenna. I have the antenna on the dash, in the far right corner next to the A-pillar (and right next to the Sirius antenna) and it gives me very good reception.