External + Internal Antenna Performance

[+JeepCachr]

Warning Newbie Question-

 

This may seem silly and it may have already been answered but I can't find it.

 

If you have a GPS with an external antenna does it use both antennas at the same time or does the external one take over? Would there being any significant benefit to stragically placing both the external antenna and the receiver?

[+erayboul]

I'm fairly confident that when you use an extenal antenna with a GPS receiver that it takes over and the internal antenna is no longer used. Therefore, you can mount the antenna where it does the most good and most the receiver where it is the easiest to view.

 

Ned Raybould

Columbus, OH, USA

[jbclimber]

I'm fairly confident that when you use an extenal antenna with a GPS receiver that it takes over and the internal antenna is no longer used. Therefore, you can mount the antenna where it does the most good and most the receiver where it is the easiest to view.

 

Ned Raybould

Columbus, OH, USA

I agree. Generally speaking an external antenna will give you better reception because of higher gain.

[+JeepCachr]

I don't know what gain is but why don't they make the internal antenna have higher gain then?

 

Sorry if my ignorance is showing...

[+erayboul]

Gain is a number that indicates how much the tiny signal that the antenna receives is amplified on its way to the GPS receiver.

 

An internal antenna that had extra gain would only solve part of the problem with internal antennas. The other problem is that a GPS receiver that is sitting on the passenger seat or on the dashboard does not have a clear view of the entire sky. The roof, pillars, doors, and so on are going to prevent the receiver from seeing all of the satellites that are overhead. All of the gain in the world cannot overcome a blocked signal.

[+NimravusHSSR]

Gain does not mean a signal is simply "amplified" contrary to popular belief. 2 antennas used with the same GPSr, one being 0 gain, the other being 3db gain. The antenna does not amplify the signal.

 

There is a simple explination: (see first picture)

0 dBd gain antenna radiates more energy higher in the vertical plane to reach radio communication sites that are located in higher places (vice versa for reception). Therefore they are more useful in mountainous and metropolitan areas with tall buildings. A 3 dBd gain antenna is the compromise in suburban and general settings. A 5 dBd gain antenna radiates more energy toward the horizon compared to the 0 and 3 dBd antennas to reach radio communication sites that are further apart and less obstructed. Therefore they are best used in deserts, plains, flatlands, and open farm areas.

 

 

An external antenna or a re-radiator will almost always significantly increase the amount of sats aquired and increase signal strength vs a GPSr in a vehicle.

 

A Re-radiator does not need a physical connection between the antenna and GPSr. It takes the signal from an external antenna, amplifies and re-radiates it in you vehicle for an amazing increase in signal strength. As you can see, the amplifier is powered via 12v power source.

 

 

Here is my GPS V on the dash with open sky:

 

Just a few seconds later, nothing has changed except I turned on the re-radiator:

 

As you can see, the increase is significant. A re-radiator is a must in my opinion. Who needs an external antenna that needs to be connected and disconnected every time! And if you have ever said "I get reception just fine without an external antenna".... well, just look above!

Edited March 13, 2004 by FlashMaster

[dccbasser]

where do you mount the antenna part of the re radiating external antenna. would it benefit me in my boat.

[+bob393]

FlashMaster, Good explination.

 

Where did you get your Re-raditor?

 

I like the idea just so you don't have to plug the antenna in and out when you take the GPS from the car.

[+NimravusHSSR]

Thanks. As you can see in the picture, there is a normal external antenna, the one that comes with the vortech is magnet mount low profile. You can use any GPS antenna with the right connector.

 

You can use a marine antenna for your boat, mount it outside and with the re-radiator inside your cabin below, you'll get full max reception possible! You can walk around below deck with a handheld and get readings from the external antenna with NO CONNECTION.

 

There are cellular phone re-radiators also for in-building use. Wilson Antennas makes them for cell phones so you can have reception in a cement basement if you want. You can get a er-radiator cell phone repeater with 3 watt boost too!

 

I have a GPS Re-Radiator for sale in the Garage sale if anyone is interested If you've ever used an external antenna, imagine more signal (this is a true amplifier) with NO MORE PHYSICSALLY CONNECTING the gps every time.

Edited March 14, 2004 by FlashMaster

[+apollo08]

Also if you are using an external antenna, it is probably mounted onto some sort of metal holder. This metal increases the ground plane of the antenna making the antenna more efficient. The internal antenna does not have any ground plane. They say that if you use a metal frying pan under a Ique3600 one does not need an external antenna!!!

[+JeepCachr]

Also if you are using an external antenna, it is probably mounted onto some sort of metal holder. This metal increases the ground plane of the antenna making the antenna more efficient. The internal antenna does not have any ground plane. They say that if you use a metal frying pan under a Ique3600 one does not need an external antenna!!!

Just what I need a frying pan mounted on my dash...