18″ radome testing, part 1


“The fog was so thick that…” is a popular line here on the coast of Maine, especially this summer.  Well, it was so foggy yesterday morning that we didn’t actually see this can buoy until it was just a little over a boat length ahead, and, yes, as the photo suggests, it was so glassy gray calm that fog and Bay blended into blank oneness.  But the amazing thing, I thought, was that the new Raymarine Digital 18″ radome I’m testing captured this can about 3/4’s of a mile away and held it tight and clear almost right to that boat length visibility distance.  These are great days for real radar testing…

Below, click to enlarge, is Gizmo’s upper helm last Saturday, before we began our week-long “research” cruise (a shout out to my sweeeet wife Andrea is due here).  You can see that the Broadband Radar connected to the Simrad NX45 is at 400′ range and resolving Camden Inner Harbor quite well (it did even better close in when mounted much lower on Li’l Gizmo)…


I’ve learned to expect that near range performance from the BR24, but was pleasantly surprised when I turned on the Ray dome.  It did darn well at its minimum 1/8th mile range, and, as noted above, has been keeping that promise in real underway use.  Has anyone seen another 18″ magnetron radar resolve this well close in?  More photos will be coming, including results from a Garmin 18HD, which is on the boat but not yet swapped on the mast.
    Another little surprise was that the BR24 imagery went completely whack when I turned on the Raymarine dome, mounted about a foot below it, and it’s also getting occasional interference spokes from nearby vessel’s scanners.  The former means I can’t run both radars at once, but the latter is just a little annoyance.  Plus there may be a BR interference adjustment I haven’t found yet.  The Ray dome, on the other hand, takes 70 seconds to achieve standby status and when running sometimes interferes with the GPS reception of the PB200, mounted in its beam (doh!) about 4′ away.  Going foggy island hiking today…more soon.


Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

3 Responses

  1. Ray Hermes says:

    It is interesting that Raymarine doesn’t actually have an 18″ radome! Instead, it is almost 21 inches in diameter. And their 24″ radome is 26 inches. They are also about 25% heavier than competitive products as well.
    I thought they looked a lot bigger but I wasn’t certain until I checked the specs.
    Are you going to compare it to the Furuno DRS2D performance as well?

  2. Patrick says:

    It seems these units draw a lot less power which is a great thing, but what are the benefits of this to the ocean going cruiser?
    Any better long-rage resolution?

  3. catamaran guy says:

    Raymarine dome sizes
    Yes its a bit misleading…but the actual arrays inside the domes are 18 and 24 inches.
    Raymarine earlier analog domes were smaller diameter but they were redesigned to comply with EC radiation rules.The older analog domes had sidelobes
    (downlobes?) that radiated too much RF directly below the dome.The new domes comply with the EC rules.But they had to be a bit bigger.
    weight?Well they are 21 pounds..I don’t think that’s too heavy for a 4kw.

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