DIY Radar Install

It’s cheaper to do it yourself, but is the hassle worth it?

October 3, 2012

Radar splice

My cable splice. Only Furuno seems to make stand-alone monitor/antennae packages and I see the blue and white Furuno name on all of the commercial fishing boats. I decided on the 1715 and paid about $1,800. Michael Robertson

Of course, when we bought our radar unit I didn’t go with a full-service electronics retailer and pay for installation. As a cruiser, I have the time to install the thing myself and in doing so, I’d learn all about the installation, knowledge that will likely help me to troubleshoot problems down the road. Besides, it’s cheaper to do it yourself, right?

I decided on the Furuno, I compared prices, and I ordered the thing. I didn’t think to specify the length of the monitor/radome connector cable. I noted that it came standard with a ten-meter cable. Super!

In San Diego, I hired a rigger to rivet the radome mount on the front of our mast, about nine meters up. I didn’t give the cable length a second thought during the two hours I spent trying to fish the cable past obstructions on the mast interior and then out through the tiny hole at the base. But I’m no dummy, less than five minutes after completing that job, I realized my mistake.


Online, I saw that for $450 I could buy the 20-meter cable I should have started with. Because I’d scratched the sheathing wrestling my cable down the mast, I could no longer claim a $175 credit to exchange it. I looked at the blood on my knuckles and recalled the hassle and luck it took to run that cable; I didn’t want to do that again just because it was 20-feet too short. For a short time, I considered mounting the monitor beneath the floorboards, just beside the mast step, but I couldn’t think of a way to sell that idea to Windy.

Google helped me to find a million dire warnings online against trying to splice radar cable (and some folks who had done it successfully). I closed Google and opened Skype.

“What if I cut off the monitor plug and splice in 20-feet of common wire to match whatever is inside your sheathed cable?” I asked the technician at Furuno headquarters.


“No way. Under the plastic sheathing is metal mesh sheathing, ten insulated copper wires, and a coaxial cable. If you splice in unprotected wire and coax, you’ll get too much interference, it won’t work.”

“What if I buy another $175 cable, cut off the monitor plug of my existing cable, cut off the radome end of the new cable, and then splice those?”

“Uhmm…” I felt a surge of boundless hope in the technician’s pause, “…it might work…” I took that as an emphatic assertion that it will work, “…but you’ll have to be very careful splicing he coax, use a plastic terminal bar—the European style—and make sure the entire splice is in a watertight metal junction box…we don’t recommend this though, you’ll kill your warranty. By the way, when you’re done, you may have to adjust the sweep timing to account for the longer cable—there are steps in the manual for this.”


So I had a plan and with the help of my friend Dr. Stewart in Eureka, I tracked down the cable, terminal strip, and junction box I needed. In a day I finished the installation of the radar I’d bought three months before—and it works like a charm.

It was a hassle to take the do-it-yourself approach, but I spent less, I know much more than I would have had I hired out the installation, and if we ever decide to pull the mast, it will take me about five minutes to disconnect the radar cable. Bonus.

This is what radar looks like in a crowded area with the range set to 6nm. We are in a marina in the half-mile blob in the middle of the screen. The vertical mass that extends out of it, up and angled off to the right, is the Columbia River bridge in Astoria, OR, meeting the dark mass of land about four miles away.
It’s better on the ocean where buoys, boats, and even whales show up clearly against a relatively empty background. In the case of whales, as Windy called out the positions of three of them the other day, their backs were out of the water, and I could see them on the display.


I__n our twenties, we traded our boat for a house and our freedom for careers. In our thirties, we slumbered through the American dream. In our forties, we woke and traded our house for a boat and our careers for freedom. And here we are. Follow along at


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