Radar Mount

hrbucher · Posted: Fri Oct 27, 2006 5:30 pm Post subject: Radar Mount

I own a C-dory 25 with the radar bow factory installed. To mont the radar is it advisable to install with down tilt to compensate for bow up. If so what is the recommended down tilt?
Thanks Hans

journey on · Posted: Fri Oct 27, 2006 5:54 pm Post subject:

The vertical radar beam subtends an angle of ~30 deg (at the 3 dB points.) That's 15 deg. below the horizon. I wouldn't worry about it or just mount it with 5 deg. tilt up.

Not knowing where you're mounting the radar, I hope it's not on a aft mounted radar arch, or the beam is going through you every time the radar goes through a scan. On the other hand the pulse (chirp) is of small duration. Try to mount it in the front of the cabin top. That's why Journey On's radar arch is in front and as high as I could get it. According to Judy, I've lost enough brain cells already.

Boris

tpbrady · Posted: Fri Oct 27, 2006 8:54 pm Post subject:

Boris,

You got me thinking about my Furuno 1623 on a rear mounted arch. The vertical beam width is 25 degrees. Just looking at it from the side, it looks like that runs it right through the windlass on my CD22. If it was mounted on the front it would be going through my head on the stern. I am sure that would be the same on the 25.

That said, I don't think the power out on most smaller radar's is great enough to worry about either inside the cabin or in the cockpit regardless of the installation location. I draw the line on working on the roof with a dinghy or kayak with the radar on. Most of the time mine is off (standby) unless I'm running.

Little Catelyn · Posted: Fri Oct 27, 2006 9:26 pm Post subject:

Well this is interesting... When our boat was on order I used the drawings on the C-dory site and added a radar arch to scale. Seems to me that the rear-cabin location offers just enough forward while providing a clear area aft. Hopefully this will prove to be a non-issue with the smaller radars we are using -- but, definitely worthy of consideration.

Corwin

thataway · Posted: Fri Oct 27, 2006 10:48 pm Post subject:

The usual "Wedge" is 3 to 5 degrees. As noted the vertical beam width is 25 to 30 degrees-but you like to have it as near the horizontal as possiable. Also remember what attitude you will be running the boat in limited visability (probably not on planing mode--but either a displacement or semidisplacement).

SeaSpray · Posted: Sat Oct 28, 2006 12:16 am Post subject:

Just a thought. Would one of the microwave leak detectors be able to detect the radar beam if it were comming through the cabin?

Steve

thataway · Posted: Sat Oct 28, 2006 12:59 am Post subject:

I cannot answer if the microwave detector will detect it or not. We mount our radar directly over head of the helm station--Marie has a pacemaker (for 25 years)--so we are very much aware of unshielded microwave radiation--no probelm with the radar. My thought is that the radar arch is high enough above the passanger's head, that they will not be in the beam. Remember this is a total beam of 30 degrees, 15 above and 15 below the plane of the radar's axis.

I certainly do not advocate anyone putting their head or gonads in the radar beam!--Although it is generally felt that it is reasonably "safe"--you see all of these folks with radar on the flying bridge, or on a mast right behind their heads--not a good idea--but they seem to get away with it.

DaveS · Posted: Sat Oct 28, 2006 1:32 am Post subject:

Sneaks · Posted: Sat Oct 28, 2006 11:06 am Post subject:

Sneaks · Posted: Sat Oct 28, 2006 11:42 am Post subject:

Added note: Our illustrious Ancient Mariner, Dusty, should by all accounts be glowing in the dark by now from both reflected and direct radar exposure throughout his military career and recreational boating pastimes. Carrier radars have unwanted side lobes in every direction that in themselves, are many times more powerful than the average Raymarine 2-4kw system, and they often reflect right into the bridge area, not to mention the aircraft (and their pilots) get painted pretty well while launching and landing. He seems to be immune to Old Timer Disease, and his son, concieved during his career seems to have better than normal genes, so I can only comment that long term exposure may have some benefits as well....

Byrdman · Posted: Sat Oct 28, 2006 12:04 pm Post subject:

OK, just how hard would it be to rig up something like NASCAR has to change the "wedge" on the car set up.. Hummm... Crank it up if yer going to be cruising at speed for some time.... crank it down if yer going to be going slow due to fog of just that is what ya want to do.... poke'r about mid-way if your are jumping about the area at different speeds.

Surely this is not a new idea.

Now having said that... if you have a CD22 ya need to take a look at the radar set up on Terry from NY boat "Last Dance." Simple set up...and a "wedge-y" thing might not need much fix-en to pull it off.

Sawdust · Posted: Sat Oct 28, 2006 12:26 pm Post subject:

Thanks, Don!

I needed the reminder - yep, I do glow in the dark. When I was with the Atomic Energy Commish my badge went off scale so many times they wanted to recycle me Wink

I can't believe the small amounts of energy from our little 2-4 KW units can be harmful unless you were to sit on the gadget for a few days... but I sure don't know. There have been a jillion studies on this, but I'm no longer in the loop so clueless in Oak Harbor I be.

I like the aft location for the radar arch on the CD - although I've usually had the radar mounted forward - and if there is another C-Salt it will have the aft arch. Good place to stow fishing rods. Fish? Gotta go.

Dusty

Sneaks · Posted: Sat Oct 28, 2006 7:26 pm Post subject:

Dora~Jean · Posted: Sat Oct 28, 2006 11:35 pm Post subject:

Jan'05 I asked Raymarine's technical support team re potential hazard of mounting the radome too close to the top of people's heads (mine primarily!) in the cabin. I have since mounted it on a 6" Power Tower simply because it's sturdier now that I have a large backing plate under it. Their answer might be useful to this discussion.

Question:
Customer (Steve S) 01/12/2005 02:40 AM
I own an SL72+ unit with the 24nm, 18" radome/antenna. The performance is excellent and has most likely saved me from at least 1 high-speed, head-on collision in the fog over the 2 yrs I've been using it in So. Calif.

My question is radiation or electromagnetic danger from this unit (while ON). I've read your FAQ and the manual thoroughly. I temporarily set the radome directly on the cabin roof where I wanted it then measured distances from my head at the helm to the radome edge (passengers are further away). The plane of the base of the antenna is approx 13 inches above the top of my head while I'm seated. The straight distance from the outside edge of the antenna to the closest point on my head is about 30 inches. The manual recommends 36 inches or more. Should I purchase a 6" Scanstrut and mount higher for better protection?

Thanks.

Response:
Question Reference #050112-000003
Product Type: Radar
Sub-Product: Closed Radome Antennas
Type of Question: Installation Advice
Date Created: 01/12/2005 02:40 AM
Last Updated: 01/14/2005 07:29 AM
Product model name: SL72+

The radar of today are frequency driven rather than the older ones which are power driven and those are the ones that may cause problems. The only thing that you should be concerned about is if you or a passenger has a pacemaker, other than that the radar you have will not harm you.

Paul Ganong
Technical Support Specialist
Rayamrine Inc.
http://www.raymarine.com

Byrdman · Posted: Sun Oct 29, 2006 9:38 am Post subject:

Hey Sneaks... Did you get the part about the pacemaker?? Mr. Green

Dusty: Man...I thought you glowed at night just because of that big ol smile!! Smile

Looking forward to seeing my left side friends in Jan.

Good talk here.,., with or without wedgies... NASCAR in Atlanta today... Watch for the wedge action.