Exterior Antenna Limitations

Is this for a extremely loooooooooooooog lemo?

I have no idea but I can't imagine why I would care. I have no need of an outside antenna.

A couple of years ago I had a GPSMAP 76Cs and I used an external antenna because I couldn't get a signal in my wife's car unless I held the unit up to the window. When I swapped it for a 76CSx with the more sensitive receiver I gave the external antenna away to someone else. I get lots of satellite signals on the 76CSx even sitting at my desk inside my house. My nüvi 760 hasn't needed an external antenna either. It seems likely that only older units with outdated receiver chips or perhaps a unit used below decks on a boat would need such an item.

Sorry for the reply that doesn't answer your question. I'm a bit curious as to what prompted you to ask.

Just for GRINS !!!!

That's quite the antenna, Paul! I don't know the answer to the question, but you may want to call Gilsson (http://www.gilsson.com/contact.htm) to ask those questions. They may be able to make a custom one for you.

Thrak, I have a vehicle that has a solar coating on the windshield that is metallicized and prevents the signal from being strong. That's why I use an external antenna. Works like a charm!

Concerning signal loss, I do know that an external antenna attached to a wireless network adapter for Wireless LAN loses roughly a decibel for every 1.5 meters of cable, less when low loss cable is used. If I use my 12db super antenna i want the least amount of cable possible to my computer for the least loss. I also know that signal boosters can be used in that circumstance. So I think you can count on a calculated loss probably to no signal at all at the end of 100 feet of antenna cable, but perhaps a signal booster could be used. Although I have not provided something you can work with here, I hope I have helped point you in the right direction. Look for online stores that specialize in this. They will have some good answers.

Thanks, I'll have to check with Gilsson and see what they can do. Especially since they have amplified antennas.

Make sure you are using the proper coax for the job. The biggest mistake people make with antennas is not using the proper cable. The reason there are hundreds of cable types is because there are lots of uses. Make sure to find out if it is 50 or 75 ohm.

I do know off the top to not use CATV wire you might have laying around...too much loss.

I'm sure you know this Paul, but it is for others benefit as well.

Daniel

GPS operates at 1575.42 MHz. I operate ham radio on the 900MHz band. At 900 MHz, good design is to use very low loss coax such as Times Microwave LMR-400 or Belden 9913 and keep the run under 50 feet with as few patch cords and splices as possible. GPS is going to be even less tolerant to long cable runs. Also use connectors rated for 1500 MHz or better, e.g. BNC, N, mini UHF - good / UHF PL259 - bad.

Hope this helps.