All done, and it works!

Here is a breakdown of how to do it:

1) Do your homework and pre-plan a lot. Realize that the one 50' cable (supplied with the HD18 radome) will not reach all the way. Order extra cable (CAT5 data type). One piece of 25' patch cable is needed for the interior conduit sections. Then another good Garmin cable section for the binacle. A total of 80 feet was needed.

2) Start by dropping the chart-display cable down the binnacle post. One plug end has to be cut in order to fit down the post. Save the cut plug end! (see "crossover cable" below).

3) Climb the mast to start the radome installation. Mark hole locations and check several times before drilling. Drill holes, careful not to drill far into the empty mast to avoid any halyards, etc. Pop-Rivet the mount to the mast. Be sure to have a really strong pop-rivet tool to snap the steel rivets. They are hard to snap!

4) Drill one 1/2" hole to feed the radar cable down the mast. Start with a steel snake and send it down to the bottom of the mast. Have a buddy at the bottom fish out the end. That took 45 minutes itself. Have the buddy tie a messenger line to the snake, and pull up the line out of the top mast hole.

5) Hoist the pre-assembled radome and shelf with cables attached up to you waiting at the spreaders. Attach the shelf to the mount and secure it.

6) Attach the cables (plug ends cut off, saved) to the messenger line, and with buddy, send it down the mast. Be sure the hole is smooth (file it smooth) and use a rubber grommet. Finish radome installation, all bolts, wire covers, keeps, and silicone sealant. Adjust radome to tilt slightly downwards to front about 3 degrees (the boat bow will rise when underway with power).

7) Now you have cable ends 1) at the base of the mast, and 2) right below the binnacle in the aft cabin. Connect them with a single 25' length of CAT5 patch cable. Run the cable though all the PVC conduit pipes all the way back to the transom. One junction box is under the foremost single seat starboard compartment, the other junction will be in the aft cabin ceiling box.

The trick is (ask me how I know...) the Garmin cables have different ends (orange and green wires switch positions) and are called "crossover". Most cables you buy are "patch" type, and don't switch positions. Your saved plug ends will save the day. If you lose one (like I did) you can fiddle with the wire positions and get it correctly wired, then it will work.

8) Hook up the radome power wires to the fuse box for 12V power.

9) Power up and be sure it works! (It did)

With this Garmin HD18, I can see as close as the next dock over, and the whole rest of the marina docks, with an image shape that is clearly recognizable.

I can't wait to go test it out while underway, to match the radar image to what I see around me. Marker bouys, kayakers, other boats, bridges, etc.

Total time spent = 3 full days x 8 hours

Day one- Drop cable from Binacle, preassemble radome and mounting shelf
Day two- Climb mast, mount radome, drop mast cables
Day three- Run interior wiring, make connections, then turn on the radar.

By doing the installation myself I figure to have saved about $2000 in labor, and avoided the pain and frustration of having someone else do it slowly and by the hour. And, I know where everything is, in case I need to access connections.

Try it yourself! -Rick

Photo Captions:

1) Cables dropped into aft cabin from the binnacle post tubes (the second cable is for the "heading sensor" which will sync radar to GPS chart).
2) Radome shelf mount bracket with the dampened swing mechanism in it.
3) Ladders set up to help climbing up the mast w/ bosun's chair & halyard.
4) Working up at the spreaders with snake, mount already attached.
5) View of radar on boat.
6) Close up of final installation.
7) Typical image (taken from the manual, but fairly true to real).