Information on mounting a radar dome?

Gundog · 02-16-2005, 09:15 PM

I am going to be mounting a radar dome on my new boat a NR Seahawk. I have ordered the boat with a radar arch. I would like to mount my VHF antenna and GPS antenna on the arch as well. I have plans on mounting some rocket launcher pole holders for holding some fishing poles also. My question is will these things afect the radar antenna? Will I have to mount the radar dome above these obsticles?
Thanks Mike

Onokai · 02-16-2005, 10:08 PM

The higher the better. As far as interferance- My t-top radar was showing interfer from my outrigger holders on the same plane.I built a 4 inch alum riser and that solved the shadow problem- the outrigger mounts were almost 2 feet away. The only way to know is put it up and try it. We hand held the thing up until the shadow was gone at 4 inchs above the t-top plane. Then built a riser. my VHF antenna and GPS antenna do not show up on it. The taco outtrigger holders are solid 2 inch diameter s/s tubes.They did show up .Mark

Poi Dog · 02-17-2005, 05:13 PM

You want to be sure to keep the GPS antenna off the same horizontal plane as the radar, as the radar can fry the GPS. It's probably best to extend your GPS a few inches higher than the top of the radar, but you can also go lower. It is very unlikely that you would get any interference from your VHF or GPS extension pole, but if you did, your radar should have a programming function that allows you to black out sectors that may have permanent interference from portions of the boat (e.g., large mast heads, flybridges, etc.). Of course this can leave you with a blind spot for that sector, but usually it is so small (a couple degrees)as to be undetectable on the display, especially because the boat bobs around more than a few degrees in the waves or current. I have my all around light about 8 inches behind my radar, and my VHF antenna about 3 feet from the radar, and neither shows up. I have a Furuno 1715, which is a relatively lower end radar with a 5.2 degree beam, but it is possible that a higher-end, more narrow beamed radar could pick a slight interference at that close range, but not likely. It will just take some experimenting to get it tuned right and practice interpreting what you are seeing, but once you get it figured out, you will wonder how you ever got along with out one. The only downside to radar, and other electronics for that matter, is that we can sometimes become so reliant on them that we neglect basic seamanship and common sense.

bait boy · 02-18-2005, 08:03 AM

Poi dog, Got a radar huh? ready for a few more of those late night starts to the tuna grounds?

backlash442 · 02-18-2005, 08:47 AM

Did you order the O/S Seahawk or one with open bow?

Don't think it will have any affect. My old boat had rocket launchers on the back of the roof and never had a problem. My friends all have rocket launchers or rescue pods that are at equal level of their radar w/out any problems either. Only thing though is there is quite a bit of space between the radar and the launchers or rescue pod.

Poi Dog · 02-18-2005, 05:57 PM

Yeah Rick, but of course I "won't forget my Bait Boy." Are you still up for some runs out of the CR this summer? I've also got some photos I need to send you from the last run out of Depoe Bay.

Gundog · 02-21-2005, 10:54 AM

backlash442,
I have been out of town and unable tyo answer for a few days. No my Seahawk is not the O/S just the standard 21' model with soft top.

PoiDog,
Thanks for all the info.
Mike

backlash442 · 02-21-2005, 02:09 PM

So then your radar will be fairly close to the rocket launchers correct? No experience there.

My old gps antenna was right next to my radar but was almost flat. Neither interfered with each other.

Most of your fishing going to be saltwater?

Gundog · 02-21-2005, 06:27 PM

Ok here is a picture of what I think I am getting. This is not a picture of my boat but a picture from NR web site the only one I could find that shows a radar arch.
Mike

On my boat I will still have the regular canvas this boat shows a shortened version my radar arch is going to be even with the back canvas.

NorthRiverRick · 02-21-2005, 06:53 PM

Gundog,

My rocket launchers don't seem to affect my radar.

Go here web page

By the way that NR pic is a couple years old at least. They just started offering arches in the last year. Yours will be similar but not quite like that one.

Gundog · 02-21-2005, 07:02 PM

I have one more question for now. I have ordered my VHF radio and antenna and mount I need to go pick it up. My antenna is 8' could I get by with a 4' mounted on the arch?
I am afraid it will stick out to far in the back when I lay it down to travel if I use the 8' antenna.
Mike

Onokai · 02-21-2005, 10:55 PM

Go with an 8 footer. They work on line of site. If it sticks out behind to much fold it forward instead. Mark