2 GPS to One Aerial Stupid ?

[IanR]

I have recently come into possession of a Garmin GPS/chartplotter and am thinking of hooking it up to the same aerial as the GPS on my aging NKE system. I have checked it works on its own to the NKE aerial cable.

Are there any "Sparks" out there who would be able to tell me whether two to one is a sensible option by linking the aerial to both receivers ?

Thanks
Ian

 

[brian_neale]

Sensible? Not really! Never going to give as good results as dedicated aerials.

Will it work? Probably give you some signal, but weaker than with dedicated aerial per GPS, so have a look at the signal strength display if there is one before and after.

My main concern is if it is some kind of "active antenna" that contains electronics that may be damaged. Raytheon have some devices like this, but in your case it sounds passive. That means little danger of damaging anything, and the worst that will happen is that it just will not work very well!

By the way, how would you split the signal? "Proper" antenna splitters will reduce the signal by about half for each receiver. Just trying to splice in a second cable by stripping the first and tapping in the second is likely to lose you much more than that, and leave a cable that will need a proper connector and joiner to repair without signal loss (or not appreciably, anyway).

But if you feel experimental, I would be interested to hear the results!

 

[Chris_Stannard]

I am pretty sure the Garmin antenna is passive, do not know about the other one. If it is a powered antenna the it might upset your Garmin by passing power to the Garmin, although this sounds unlikely. Why do you want two GPS on at the same time, why not use one and keep the other as an emergency set.

Chris Stannard

 

[Bergman]

I would be very surprised if the aerial unit were passive. Trying to pass those frequencies down a random length of coax is not likely to be successful.

I would suggest that you try measuring for DC volts on the aerial socket of the GPS. If none present then give it a try.

If DC volts present don't try conecting second set, almost certainly it won't work and may do damage.

If you do have a go I would suggest that you get a BNC T piece connector, connect the "stem" to the aerial and each end of the "cross" to a GPS set and hope for the best.

There will be a minimum of 3 db loss to each set but that may be acceptable.

I would be very hesitant to take cutters to the cable and try twisting wires together. Not likely to work well.

Best of luck

 

[Guest]

I don't know about the electronic side of it, but it would seem to me that by keeping the two GPS systems completely independant by using separate aerials you will have a backup system if one fails. If they both use the same one and it develops a fault then neither gps will work

 

[ccscott49]

I agree, keep em' seperate, then its total backup!

 

[IanR]

Thank you all for the concensus. It never occurred to me that this would be an active aerial. A timely warning indeed.

Off to the market place to buy a seperate aerial.