GPS ANTENNA ADVICE NEEDED

Rabbits Hutch · Posted: Sat Jan 29, 2005 2:09 pm Post subject: GPS ANTENNA ADVICE NEEDED

I am purchasing a Raymarine GPS/Chartplotter for my new C-Dory, a 16' Cruiser.

I would much rather have the integrated, internal antenna that comes within the plotter itself requiring minimal wiring. My concern is if it will lock in a strong signal in a timely fashion? Do I need the extra insurance of an external antenna mounted or is an integrated one just fine?

Hopefully I will have the answer by the end of this weekend.

Thanks !!!!!

Casey · Posted: Sat Jan 29, 2005 2:41 pm Post subject:

I have a Raymarine GPS on Naknek and simply velcro the antenna on the shelf above the helm. The antenna gets the GPS signal just fine "through" the fiberglass top. Same situation using a small Garmin handheld with build-in antenna - it works fine anywhere near a window.

Give it a try - before drilling any extra holes in your new boat! You'll probably find you don't need to drill.

Casey
C-Dory Naknek

Rabbits Hutch · Posted: Sat Jan 29, 2005 3:06 pm Post subject:

Thanks for the guidance.

GR

katkt · Posted: Sat Jan 29, 2005 3:09 pm Post subject:

The dealer mounted mine in the corner behind the wallas,
mine always tracks the sats fine. Smile

Chivita · Posted: Sat Jan 29, 2005 3:12 pm Post subject:

I have had similar sucess as Casey but with a Garmin external mushroom style antenna mounted on the small shelf above the pilot's head. It pulls in the same number of satellites as when I tried it on top of the cabin roof, but I cannot claim this as my idea, Les suggested I try it and it has worked quite well.

The higher your receiving antenna (internal or external) is mounted, as well as the minimum amount of metal between the antenna and the satellites seems to result in the highest number of signals your GPS will receive. The fiberglass thickness in a typical C-Dory does not seem to interfere with the signals.

I have a small portable GPS with an internal antenna as a backup and although it seems to take a minute longer to aquire signals, so long as I have it sitting on the shelf in front of the wheel, it too works well. If you really want to be sure, see if you can borrow a friend's portable GPS (or try your local boat shop) and try it in the same location as you want to mount your Raymarine. That Raymarine set up you are purchasing should have a bigger/better internal antenna than a hand held GPS.

"Chivita" Dave

Chuck S · Posted: Sat Jan 29, 2005 5:42 pm Post subject:

I've been running a pair of GPS receivers in the cabin with NO external antenna. Non is needed. One less cable to run. One less hole in the ceiling.

-- Chuck

Rabbits Hutch · Posted: Sat Jan 29, 2005 10:25 pm Post subject:

OK, so now I know.... no external antenna needed. As my Raymarine search continues, I discovered today that the C70 system will be expandable to include radar one day. Probably wise if I take that route. As the C70 has the requirement for a GPS antenna, perhaps I can have it mounted inside the dashboard, forward, by the windshield.

In the 16' Cruiser, there is no shelf other than that small and level area forward of the steering station.

Does that sound like a plan???

Thanks again for the guidance.

Gary R

dogon dory · Posted: Sat Jan 29, 2005 10:56 pm Post subject:

Sorry, Folks - Post Deleted By Author

Chuck S · Posted: Sun Jan 30, 2005 11:34 am Post subject:

Hutch --

Since I never intend to fit radar to our 16 Cruiser I'm looking at the Raymarine 435i GPS/chart plotter. These run ~$800 street price ready to place on the dashboard and run. Plus chart chips, of course!

The 435i has a 6" diagonal screens (portrait oriented) (vs 6.5 landscape for the C70) and is totally self contained.

The 16 Cruiser is dash challenged, even in comparison to the 16 Angler! I may end up fitting an overhead pod, or a pod on top of the dash itself for the plotter, fishfinder, and radio. I currently have the fishfinder mounted top center of the ceiling between the wiper motors. This unit will repeat GPS data, but won't serve as a chart plotter.

-- Chuck

Rabbits Hutch · Posted: Sun Jan 30, 2005 1:10 pm Post subject:

Chuck:

The fishfinder looks great up in that location. That is one of the Raymarine units I'm looking at. Trying to decide between that particular model and the DS400x.

As for the C70, if you havent purchased your 435i yet, I would go take another look at the C70 model. The graphics are considerably better and the ability for the unit to redraw a navigational chart is light night and day. Consider it a faster computer if you will. Perhaps the antenna will go in front of the steering wheel, on that flat area, all the way forward by the window.

I've also considered a shelf.. but as you know we're so limited on space in the 16' Cruiser. As of know, my intent is to place the fish finder where yours is, have the chartplotter centered in front of the steering wheel and the VHF on the interior hardtop above the chartplotter, perhaps set a bit forward.

Thanks for your guidance.

Gary R

Chuck S · Posted: Mon Jan 31, 2005 6:41 am Post subject:

Gary --

Thanks for the notes on the C70 vs 435i. I've not as yet seen either of these units side by side and was unaware of the slower refresh, etc., on the 435.

The DS550 is mounted where it is so more than just the wheelsman can see the display. My driveway doesn't have 50 feed of water in it but these are the normal displays I use with the unit. It's picking up GPS information from my old Garmin 75. This mounting isn't optimal due to the display being in shadow and the glare thru the windshild, but on a 16 Cruiser the dash has very little room as the only place I can figure out for the VHF-FM is on top of it.

My dash layout looks like this. Any suggestions appreciated! Everything is secured at present with Velcro. This is pre-fish finder.

-- Chuck

Rabbits Hutch · Posted: Mon Jan 31, 2005 8:04 pm Post subject:

Hi Chuck,
I've just returned home from an afternoon of electronics shopping and then off to the C-Dory factory in Auburn, WA.

I once again looked at the 435 side by side with the C70. Raymarine has a unique situation with those two units, as each "reads" the Navionics Gold information a bit differently when it comes to drawing of the charts. The colors and graphics displayed on the C70 were just, for lack of a better term, beautiful, compared to the 435. I paid for and picked up the C70 today.

After leaving Boater's World, my next stop was the C-Dory factory. Scott, the sales manager, wasted no time in giving me a pair of safety goggles and walking me back to the new factory floor. Definitely a place all should visit. Scott introduced me to the "riggers" setting up my boat. They were in the process of installing my two electric windshield wipers when I showed up with my box of Raymarine toys. Together, we put together what we all felt would be the best layout. Here's what we came up with:

The C70 will be on the dash platform, centered in front of the helm wheel. It will be about 6" back from the forward edge. The VHF radio will be mounted under the hard top, towards the windshield, starboard side. As this area of the hardtop gently slopes to the side windows, they will use a thin wedge of material between the radio installation bracket and the interior of the hard top, so that the VHF rests flat. The fishfinder will be in the same location as yours. The GPS antenna will be on the hard top, centered, and just forward of the navigational light stem.

Here's a bit of information I'll just through out there. There is a new camper canvas being designed by Dave at King Marine. It will have a bimini top, quick release zipper near the hard top so that it can roll back and be secured into a boot. The two side panels and aft panel will all have the ability to fully zip on or off as needed. My 16' will be the first to have this, with many more boats to follow. I added the extra feature of zip around and roll up windows on the 3 panels to expose the screened panels for extra ventalation.

I just love this new boat. I take delivery a week from Thursday. I should take that day off from work so as to get her wet.

Gary R

Les Lampman · Posted: Tue Feb 01, 2005 7:56 pm Post subject:

Gary,

If you're installing a Raymarine C-70 MFD why is it that you're not using the depth sounder module made for it?

Rabbits Hutch · Posted: Tue Feb 01, 2005 8:00 pm Post subject:

Two reasons actually. As someone who is new to boating, I wanted to use the full screen display showing my navigational charts as i move around the sound. The alternative is a very small split screen option.

Secondly, the expense to add the C70 depth sounder components including the transom components and installation of all that is entailed is cost prohibitive at this time.

I've saved money, have two dedicated screens and will feel safer and more comfortable with a full navigational chart in front of me.

I suppose with time on the water, I will evolve in a year or two...

Luna C · Posted: Tue Feb 01, 2005 9:42 pm Post subject:

Same reason for my seperate depth finder. I like to use the full screen for the chart plotter, w or w/o the radar overlay! I think it was $600+ for the raymarine "fish finder". Since I am looking for Dungeness, I just need to know where the bottom is!