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Garmin Radar Dome

The Duke

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Hi, I am about to install a Garmin Radar Dome 18HD. What is horizontal beam width above head height as described in the manual? I intend to mount it on top of a 200mm tower on the rocket launcher which is approximately 50mm above head height. The bottom of the dome will therefore be around 250-300mm above head height when standing up. Is this sufficient head clearance room as the seats are appox. 1 meter forward of the dome? Thanks in advance.
 
While the installation manual (on line) does refer to "Horizontal Beam Width", I believe that this is a misprint. I believe that the relevant metric here is the VERTICAL BEAM width, which is specified on page 6 of the manual as 25 degrees ( +/- 12.5 degrees). If you refer to the Installation Guidelines, you will note that there is a diagram (page 2) of the installed system showing the radar beam as extending forward of the radar unit within a +/- 12.5 degree area. In brief, install the radome so that the top of the head of the tallest person on your boat, standing as far forward in the boat as possible and as far aft as possible, is well below a line extending downward from the lower edge of the radome at a 12.5 degree angle.
 
FWIW, the typical beamwidth spec is for the 3dB points...in non-techno-jargon, this is how wide the beam is where the power is 1/2 of that measured at the peak. If the human safety factory is the primary concern, you also need to consider the AVERAGE power transmitted. There are several sources that specify close but different level of what is considered 'safe'...for the most part, you're not likely to see any issues on a 'smal boat' radar....(if there were any issues, the liability risk would have removed these units from the market years ago).
 
Hi, yes personal safety is my primary concern. Sorry but don't understand the rest of the information. The unit is only a small one putting out 4kw. Am I safe to assume that if head height is below the 12.5 degree lower sweep angle of the radar then there should be no concerns? Thanks
 
If you read all the info on the new High Definition Radar units the beauty of them is the small amount of power they put out. They are similar to a cel phone that people don`t hesitate to hold next to their head for hours on a daily bases. I find it most useful at high speed to pick out logs and debre in the water.
 
Hi Hordos, thanks for the info. I am just waiting for the mounting bracket then will install. Still need to take the boat out and see what angle the boat planes at so that I can get the dome installed horizontal.

Cheers
 
If you install radar so that it is level at plane, it will be pointing downward, limiting range, when you are crawling along in a pea soup fog, or at night (I personally never go over hull speed at night) ...I am amazed at folks who run around at cruise or faster in the dark... all those unlit marks and no wake warning barrels and other misc items. Envious of folks who boat in waters with no floating debris or unlit marks or lobster/crab pot floats... :)
 
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Yes I agree I live in British Colombia and we have lots of logs floating around so my HD Radar is a real help especially when there is chop and difficult to spot logs. One of my boating Buddy's broke his leg right off with a log. Good thing he never lost the rubber boot and didn`t take on water as his wife and him were alone that time and help was quite long coming.
 
Hi, thanks for all your replies. Just a further question.... can anyone suggest the best way to protect the dome when transporting the boat via road over long distances (400kms)?? At the moment I have it screwed on with wing nuts and take it off. A bit of mucking around at the other end but not a bad option for protection and less wind drag?? Can you buy covers for them?? Thanks
 
Re:"A bit of mucking around at the other end but not a bad option for protection and less wind drag?? "
Also saves wear and tear on the mechanics/drive unit over long drives, especially if rough roads. Would hope youhave lock waskers under the wing nuts as well.
 
Went with removing and then installing it at location. Used stainless flat and spring washer with stainless wing nuts. Only took about 5 minutes to get it up and then pull down at end of trip. Put a latex rubber glove over wiring and tucked them into recess of dome tower to protect from wind and weather during 400km trip. Anyone with same sort of concern this worked really well. Thanks for your replies
 
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