Installing a Dual Masthead (Radar/SatTV)

May 4, 2012… Just finished-up installing a Garmin GMR24HD radar and a KVH M3ST satellite-TV antenna. All-in-all, I’m pretty happy with the outcome, especially after the MONTHS of work due to several false-starts due to little things overlooked in the beginning… here’s another anal-tutorial on what NOT to do…

I liked the look of the SeaView PMA-DM1-M3 mast, with its dual mounts and integrated LED all-around. Purchased it, installed my stuff on it, thought it looked pretty good in my living room:

Almost there?

Looking good, in the living-room, at-least

Got it down to the boat, then I started learning the errs of my ways…

Turns out my 3372’s arch is lower than the camper-canvas, something I should’ve realized before any of this started. Looking at any old photo of the profile of my boat would’ve highlighted this… the camper doesn’t stick-up a little bit, IT STICKS UP A LOT (11-1/2” to be precise)…

Should've Known

Should've known the arch wasn't high-enough

So, I go and install this thing with the camper-top down, everything bolts up fine… but I start noticing problems everywhere… I can’t lift the canvas-bows because they hit the mount, the angle on the mount looks goofy versus the angle of the arch, the radar is pointed down, the all-around isn’t even close to vertical…
Antenna bad-install

The antennae are installed, but not correctly!

I then dismantle everything and start measuring. Yes, I know: measure-twice, cut-once; I get it…

Turns out, the angle on the arch is a perfect 45-degree (see redneck picture below):

Redneck Angles

Trying to determine the arch rise-angle

Only trouble is, the SeaviewMount is actually closer to 60-degrees… Okay, that wasn’t the “only trouble,” turns out the 3372’s radar-arch also pitches down going fore, by around 1.8degrees:
Arch angle

The arch isn't completely level... drops 1.8degrees fore

Now the fun starts. I remove the radar, sat-dome, mast, and go back to the drawing-board… literally. I worked with SeaView to design an extension-piece that has the correct 1.8-degree base-plate, along with what I consider to be the correct 45-degree upright. See the link below for a completely bad-a$$ 3D-PDF file that you can spin my designed mast-extension and mast around… really cool. Just hold the mouse button down on the image and use your mouse to roll it around, zoom, whatever:
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. . . .Long-story long, here’s the eventual outcome:
Side view, completed

A side-view of the finished install

Antenna Close-Up

A close-up view from behind

The Final Result

The antennae are finally finished!

Yes, I realize how tall this is. I don’t hit any bridges I go through (thus-far) with my 8’ whip antenna, so I should be good (if I had to do again, I’d probably drop the extension-height about 6”). I purposely wanted to get the radar up, so the canvas-bows weren’t interfering with the return-signal and so the radar wasn’t drilling the Captain in the back of the head as he drives.

I measured my arch at 8’7” above the waterline, the front-bow is 9’6-1/2” above the waterline. The top of the all-around light is approximately 54” above the arch, or 13’1” above the waterline (a little higher if on-plane).

The only word to describe running the power and communication cables between the mast, bilge, helm, and cabin TV’s that comes to mind is “miserable.” I’d guess somewhere around 40-50 hours total, start-to-finish (not including months of actual time between manufacturers and threats I had to make with DirecTV to get anything working).

Happy Wakes!  Drop me a line anytime,

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