GPS Antennae placement?

[raylaracuente]

So I'm adding an AIS transponder on my cd27. It requires it's own dedicated GPS antennae.
(It's a vesper https://www.defender.com/product3.jsp?n ... id=4863144)
So I'm at a loss as to where to place the antennae and I'm leaning towards somewhere on the lazarette.
Has anyone dealt with this?

[Jim Walsh]

I have an AIS transponder with a splitter and the function of the splitter is to allow use of my masthead mounted VHF antenna. AIS and VHF both share the same band. AIS at the upper end and VHF radio’s at the lower end of the band. They both benefit from an antenna mounted as high as possible.

[BernieA]

I installed an AIS transponder in my CD28 a few months ago. It also has a splitter to share the VHF antenna. The GPS antenna, which provides your location to the data stream transmitted by your AIS transponder can go anywhere that it can receive signals from GPS satellites. I think the instructions recommended that the antenna be mounted in the interior of the boat instead of out in the weather. I mounted mine inside the cabin and actually beneath the electrical panel. It works fine from there. If the GPS antenna you received with the unit is a puck type antenna, mount it in a position where is sits flat rather than on edge. Some AIS units have an internal GPS antenna, so there wouldn't be a need to place a separate antenna. The AMEC 108 unit that I bought has an external antenna with about 6 feet of cable. It also has a software that I installed on my laptop that allows me to connect with a USB cable and check details, including reception of GPS satellites. That way I could move the antenna around and find a spot where reception was ok.
My AIS is a class B, which does not transmit to satellites, it only uses GPS satellites for location and VHF for data. There are AIS units that report their data streams via satellite, but they cost more and I'm a cheapskate.
In the Salish Sea where I sail, there is a lot of heavy shipping and commercial traffic, and weather can change pretty quickly, including fog. My AIS unit only transmits a few miles, but any other AIS vessel will see me and I'll see them in plenty of time to avoid collisions.

Bernie
CD28 S/V Pinafore
Sequim Bay WA

[raylaracuente]

Yep. This package from defender comes with the splitter as well that I will share with my antennae up on the mast.
It also has a separate mushroom shaped GPS antennae since it doesn't have an internal one. It also allows you to USB into your laptop and seek the best placement. This unit was recommended by Jeff Cote of "Pacific Yacht systems".
Was wondering if anyone else had to mount one of these separate GPS antennae's but it sounds like it may work well inside
the cabin!

[BernieA]

I looked at the unit you indicated at Defender. That one can be inside or outside, so you can put it wherever its convenient for you. Mine was a little 1 inch square puck that was really easy to stick anywhere. Looks like you can do whatever you want, then test the receive levels with your laptop and go with the spot that works for you. Way back when, GPS receivers weren't anywhere as sensitive as they are now. The ones in modern cell phones are amazing in comparison, and extremely small.

[mgphl52]

When I bought KAYLA in 2002, she came with a "radar arch" that has a solar panel & GPS antennae - no radar dome...
It was installed by a prior owner who did several custom mods to KAYLA. The arch was beautifully integrated with the stern pushpit and has small seats where they intersect. If you want pics, please let me know.

[SVFayaway]

I put a Vesper transceiver on my boat and mounted the antenna on the pushpit. It's a little ugly because I couldn't easily hide the cable but it's out of the way and was an easy install. I used a Sea Dog rail mount to mount the antenna. I put some conduit over the cable and zip tied it to the rail. I may yet drill a hole in the rail and run the cable through that way to make it prettier.

[bottomscraper]

Our Vesper AIS GPS antenna is on the pushpit also. I have seen them mounted on spreaders but this make no sense, the satellites are so far away a few feet higher will make no difference.

The GPS antenna may work below deck, our current Garmin GPS antenna is mounted inside under the side deck and works just fine.

[mgphl52]

With KAYLA's GPS antennae on the top of a stern radar arch, speed & location jump around quite a bit in rough seas.
My very old hand-help Garmins could actually be adjusted for a bit more latency to smooth out that issue. No such option on what I have now...

[Craig Curtis]

I too mounted the Vesper XB8000 external GPS antenna on the pushpit. While Vesper's online installation video mentions that it could be mounted down below I was thinking that it having a clear view of the sky just had to be better even while knowing that their XB6000 model only has an internal GPS chip and other devices (like smart phones) still pick up GPS signals fine while indoors.

Really happy with the device all around. Bought it purely for the core AIS feature but the ability for it to send not just GPS data and AIS target displays but other instrumentation data (speed, depth, wind) to an old iPad2 running iNavX over Wifi lessened any temptation to upgrade my ancient Autohelm ST50 system.