Gps With External Antenna

[MobileWolf]

I am looking for a GPS unit with an external antenna. Does anyone have any recommendations? I want to be able to place my gps unit in a vehicle, run the antenna so that it will be able to pick up the satellites while the unit is concealed inside of the car.

 

Thanks

[+Medic005]

Take a look at the Garmin GPS V, the antenna on the unit can detach and you can plug in an external antenna. I have the Garmin GPS III Plus (previous model to the V) and it works great.

 

GPS V link:

 

http://www.garmin.com/products/gps5/

[Neo_Geo]

FWIW I use my 60C in the car without an external antenna. I use the external antenna for traveling on planes and trains.

 

Other units include the GPSMAP 60C/S & 76C/S as well as the discontinued eMap.

 

You might also consider the mobile units like the StreetPilot III, StreetPilot 2610, StreetPilot 2650, and the StreetPilot 2660.

 

Another option would be to go the PDA route with the iQue 3600 or iQue 3200.

Edited November 19, 2004 by Neo_Geo

[+NightPilot]

Any GPS can be used with an external antenna. Many have a connector for an antenna, and most brands will work. Those that don't have a connector can use a reradiating antenna. I use one from PC-Mobile with my Garmin Legend. I put the antenna on the roof of the cachemobile and keep my GPS way inside where I can see it, not in the windshield. Plus, I can use the external antenna in the woods and get a better signal while not having to hold the GPS in my hand; this works especially well when the trees are thick and wet.

[+DustyJacket]

The Magellan Meridian Color has an external antenna connector.

[coureur des bois]

GPSmap 60cs is excellent and the antenne GA 27 excellent. May be Gillson antenna too.

 

Jacques

[+Greenjeens]

I like my Garmin 60cs and tech support has to be the best I've ever had with any portable device.

 

An external antenna jack would be a requirement for me with any brand.

I have an old Gilson/GPS geek antenna, and it improves the signal so much, wether on my car roof or on my hat clip out in dense tree cover, I consider it the best accessory one could purchase.

 

I haven't used a specific "rerediating" GPSr antenna, but with lots of experience using and testing cellular external antennas, unless there is a direct, hardwire connection, with a dedicated port, performance is usually very poor.

 

Signal transfer, through an inductive pickup has been a waste of time. Guys in the antenna biz have told me as well, how minimal non hardwired antenna pickups are.

Glass mount antennas seem to be the one exception. Perhaps it's the very small gap (thickness of glass) the signal needs to jump. I still think a hardwire connection would be much stronger.

 

-

Greenjeens

[Alphawolf]

I'm reading between the lines here, but is this a bit of a surveillance operation on vehicle movements? I've done a bit of that for someone. It's difficult to hide both the receiver and antenna where the occupant(s) won't see them. Make sure the receiver is set to silent (no beeping allowed!). The antenna must "see" the sky, so placement is problematic. An external entenna that is carfully placed in the rear window deck and covered with some ordinary object that won't look conspicuous works, if the receiver can also be hidden somewhere. Good luck.

[peter]

I haven't used a specific "rerediating" GPSr antenna, but with lots of experience using and testing cellular external antennas, unless there is a direct, hardwire connection, with a dedicated port, performance is usually very poor.

 

Signal transfer, through an inductive pickup has been a waste of time. Guys in the antenna biz have told me as well, how minimal non hardwired antenna pickups are.

Glass mount antennas seem to be the one exception. Perhaps it's the very small gap (thickness of glass) the signal needs to jump. I still think a hardwire connection would be much stronger.

 

-

Greenjeens

The re-radiating GPS antennas actually work very well, especially if you shield the internal antenna so it doesn't receive the satellite signals directly but only through the re-radiating element. Note that these antennas are separately powered and contain amplifiers to greatly boost the signal strength of the re-radiated signal.

 

While both the re-radiating type and the directly connected external antennas work well, the direct connection does have advantages in convenience. No external power has to be supplied since they get their power from the GPS unit; and the internal antenna is automatically disconnected when the hardwired external is connected so there's no need to shield it from the direct satellite signals. Here are a couple reviews of re-radiating GPS antennas indicating the performance improvement:

http://www.pocketgps.co.uk/reradiating.php

http://www.gpsinformation.org/dale/gpsant.htm

The second review even compares the same antenna and GPS with a direct connection and then using the re-radiator transmitter. Both methods were about equally effective.

[+NightPilot]

There is no comparison at all with the cell phone antennas. A reradiating antenna uses its own power source to amplify and retransmit, or reradiate, the GPS signal. Putting it near the GPS receiver antenna boosts the signal by a lot, assuming the unit isn't getting a direct signal. It doesn't work that well if the GPSr has a good view of the sky, because you get some interference, but if the GPSr is inside a car, or under heavy, wet tree cover, it works very well. If you cover the GPSr antenna and the loop from the reradiating antenna, then you'll cut out the direct reception, and the reradiating antenna will boost the signal very well, although it may not always be necessary, just like the direct-connected antenna isn't always necessary. Another advantage of a reradiating antenna is that it has its own power, and doesn't draw power from the GPSr batteries. The batteries in mine last for weeks using NiMH batteries, and this week I inadvertently left the batteries on all day and all night, and discovered it late the next afternoon. The LED was as bright as ever, and I noticed no loss of voltage. I turned on my GPS in the truck, and got an immediate strong position.

 

Surveillance systems use cell phones for both determining position and for sending that position. GPS is used only peripherally, and not necessary on most. The cell system does the position determination, based on the known position of the towers and the signal transmitted from the device. The cell phone is necessary for sending the signal anyway, and trying to use an actual GPS for position is a waste of effort.