Add second GPS

Flying_Nun

Flying_Nun

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Flying_Nun
I think I already know the answer but if you add a second GPS, say a 430W, do you have to add a second antenna? Or can both units use the same antenna?


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There is a splitter that you can use to share an antenna, as long as both units use the same type of antenna.
 
@weirdjim, is your splitter kit available?
 
There exist splitter systems, as noted above. But...

I'd seriously consider not doing that. Unlike your other antennas on the plane, the GPS one is active, not passive. There's electronics in the antenna itself and those electronics fail. If you're sharing, all your satnav fails when the antenna fails. It doesn't add much to just run a new antenna, especially when you factor in the cost of the splitter and wiring that. Might as well get even more redundancy when you have a chance to.
 
And, just for $#!+$ and giggles, we've been sharing VOR/LOC antenna (the catshwhiskers on top of the vertical fin) for about 60 years. Any reports of smoking holes in the ground because we didn't put another antenna for the second VOR/LOC receiver? Or one single report of a failure in the FAA files?

Jim
 
There are approved splitters being used on part 25 aircraft, I don’t understand why this hasn’t really shown up in the part 23/CAR 3 worlds but the ones I’m talking about cost as much an antenna. There is small savings on installation with a splitter and of course no antenna real estate issues since you’re not adding any.

part 25 aircraft antenna installation is often a lot more work accessing the fuselage skin, installing doubler, running coax, and pressurizing the airplane for leak checks when the sealant has cured.
 
weirdjim said:
And, just for $#!+$ and giggles, we've been sharing VOR/LOC antenna (the catshwhiskers on top of the vertical fin) for about 60 years. Any reports of smoking holes in the ground because we didn't put another antenna for the second VOR/LOC receiver? Or one single report of a failure in the FAA files?

Jim
Click to expand...

If you're referencing my suggestion that GPS not be shared, I was being specific to GPS. VOR and LOC antennas are passive and the splitter is passive. It can fail, but we're talking about a small number of big parts and big cables and big signals. GPS isn't quite like that, as I know you're well aware. It's tiny, active, powered parts, signals under the noise floor, and skinny cables. And a splitter for GPS is also active. So, instead of extra redundancy, you've strung two active boxes together where either can fail and bring down both nav boxes. It's not the end of the world; the splitters and antenna are generally very reliable. But, still, given that the little antenna is about the same price and size as the splitter, unless you're really squeezed for space on the aircraft (and I know there's a minimum distance between the two antenna), why split?
 
weirdjim said:
And, just for $#!+$ and giggles, we've been sharing VOR/LOC antenna (the catshwhiskers on top of the vertical fin) for about 60 years. Any reports of smoking holes in the ground because we didn't put another antenna for the second VOR/LOC receiver? Or one single report of a failure in the FAA files?

Jim
Click to expand...

Jim beat me to it !
 
I’m using a splitter. Not sure if I like it or not. Splitter is to allow my GI275 to have a real antenna instead of the hockey puck. Both the 650Xi and 275 share a new garmin antenna. The splitter cost more than the hockey puck!
 
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