4g Radar on an older larger DA, Sundowner, EC, ect.

Im having issues installing a 4g dome on my 390ec. The radar has a 12 1/2 deg upward and downward beam angle off centerline of the dome. The instructions and advice from simrad and others is to mount the dome high enough that the nose of the boat is not hit by the beam. Since the nose is approximately 34 feet forward of the radar arch it ends up having to be mounted around 36 inches above the arch. That seems ridiculously high to me. I know someone has had to have mounted one of these on a big cruiser and not stuck it on top of a sailboat mast to get it high enough. What simrad tells me is that if I dont mount it high enough the radar will see the bow of my boat and will show it as a permanent target on the screen. Someone has to have real world experience with this. If you do how high did you mount yours. How bad is the permanent target on the screen. What if any problems does it cause. Any help would be appreciated.

I replaced the open array on my boat (original 2001) with this Garmin xHD 24" dome this off season. SR had mounted the old unit (see my sig pic) on two starboard rails. I kept those rails in place and bought a 4" pedestal, which I mounted on the same rails.

You're probably overthinking this. From the factory, many of these SRs have the dome plopped right on the arch, with nothing to raise them at all. If you want, get yourself a pedestal to raise it a few inches, finish your install and go boating.

Mine is not a Simrad but the concept is the same. I have no problem with performance of the dome.

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Do a search on YACHWORLD for sisterships of your boat for sale and take a look at how the radomes are mounted. I'm sure they aren't much higher than about 4" off the arch.

This is a photo of my friend's 2003 410DA. 45' LOA. SR mounted the dome right on the arch, zero elevation. His radar works perfectly.

Thanks for the replies. I dont think I'm actually the one overthinking it, simrad and the company I am buying the mount from seem to be. They are the ones telling me it has to clear the bow but if your not having any issues I'm going with that I'm just going to buy the 12" mount I had originally set out to. I also had a factory open array and I am also going to reuse the 2" step mounts they provided. The reason I'm going with a 12" mount over a 4" is because it also has a place to mount a spot light. Thanks, really appreciate the imput

The Simrad 4G uses and entirely different type of RADAR without a magnetron that's pulsed. I have been reading about and considering the same unit. Unlike old units, that ignored reflections from close targets, the 4G systems can see something very close to the dome. They're designed with a dead-zone for the downward facing beam lobe on centerline to avoid the problem that you described but I don't know the beam width of that dead zone.

I would recommend that you call and talk with a Simrad tech who can answer your questions because I agree that a 36" standoff is ludicrous.