I'm weighing the options of mounting the radar antenna on a pole mount at the stern rather than the mast. I see a equal number of boats at the marina with this configuration. This would solve my issue with the cable length not reaching the mast without buying an extension cable and splicing it. Installation and maintenance would be simpler. Some people have told me that the range is not affected as much as expected.
Have any of you dealt with this issue?
Mike
My rigger told me it's very difficult to get anyone to service a radar mounted on the mast. I put it there anyway...
My original monochrome was mounted on the mast so I just kept it there despite needing the extender. I find the stern gets awful crowded with the outboard, life sling, gps antenna, stern seats, fishing pole holders, Outboard lifts, etc. On the narrow stern Mk1s not sure I would want to add to the crowd. I have been told it is not a problem, but not so sure I want anything radiating that close to the cockpit either.
We have to take our mast down at the end of every season. The radar is/was mounted on the mast. I just took it off this spring, because it causes more trouble during raising the mast than it is worth (don't need it where I sail right now, but it came with the boat). It gets in the way of the sling when raising or lowering the mast. The connections have to be unhooked and hooked up every time..Make one mistake, it doesn't work, and the mast make have to come down again to fix it.
The ideal position for the scanner is definitely midway up the mast, for maximum range, avoiding radiating the crew, and a stable platform. But if I put the radar back on I want it on a stern mounted mast for better maintainability and reliability. I would look for a reasonably tall one to get a decent range and avoid radiation.
Tony
Mike,
Mine is on the stern on a high mast. It's attached to the stern rail for stability and works very well. I get good range and it's high enough that I'm way below the "negative look-down" angle of the array.
Steve
Steve you MkII owners have so much more room. You have a nice out of the way installation. To compare here is a Mk1-1.5 stern, add stern perch seats that push everything else toward the gate and things get tight quick.
Ken,
Agree. Just wanted to pass along an alternative installation.
I have a friend in Halifax, Nova Scotia that bought an '87 C34 last year in New York and mounted his radar mast on the Port side aft between the vent cowl and the stern cleat. He didn't have the stern seats but I can imagine that it would get cramped.
Steve
Steve
Can you tell us the make, model or height of your mast? Have you previously posted any info on the installation?
Thanks
Tony
Tony,
I have found out that the standard height for a radar post is 8 ft from the deck. Some are through deck mounts but the part that extends above the deck is 8 ft.
I'm also curious if the radar sees the mast as part of the display, being that the post is behind the mast.
Cost wise, it seems pretty equal because the cost of the radar post is about the same as the radar mount for the mast plus the extender cable plus rigger time.
I have a mK1.5 with the radar mounted on the stern with an 8' pole. I have had no problems with the range. Also mounted on the post below the radar is an emergency night time cockpit light that has an on/off switch mounted on the engine start panel. Above the radar mounted on the stainless ring is the GPS Rcvr. and a TV Antenna. The radar post also came with a dinghy motor lift that drops into supports mounted on the pole. When not in use the lift sits in the garage. The post was situated on the starboard side so when the lift is on it brings up the motor at the proper spot where the motor mount sits on the port side. (The motor mount is not on the stanchion in the picture). Everything is outside stanchions. The Garhauer people know all the Cat.34 models & supplied me with the proper hardware. I also added an S shaped 1 1/4" guard to make it easier to run all the cable and to mount the display.
Ron
Also another picture.
Ron
Tony,
Everything was installed prior to me buying the boat so I don't have any information except Raymarine manuals.
I can measure the mast height above deck this weekend when I launch.
Steve
Is there a minimum "safe height" that the radar dome should be mounted?
I'm thinking health and safety issues.
But if you notice on a lot of powerboats the dome is mounted fairly low just due to design considerations of the boat itself. So I can't imagine there would be much of hazard? But judging from my experience with the powerboaters that I've come across, it would seem to explain a few behavioral issues...
that's why it's mounted low...to thin the herd.
Since my first reply I spent some time researching. The average radar beam extends about 20 degrees either side of the horizontal. So if the height of the radar antenna is 9 feet above the cockpit deck, a 6 ft person would start getting hit by the beam 8.2 feet forward of the antenna post. So going into the cabin is probably safe but stepping on the side deck going forward exposes the person.
An additional bit. The optimum height above the water is to place the radom is 16'. Higher will give you farther distances, but you loose in close coverage.
I found this article on Radar Safety Issues on Sailnet. Considering the fact that safety issues are concerned, and the article is educational in nature, I copied it without permission.
http://www.sailnet.com/forums/seamanship-articles/18989-radar-safety-microwave-exposure.html (http://www.sailnet.com/forums/seamanship-articles/18989-radar-safety-microwave-exposure.html)
Quote
Jim Sexton
Contributing Authors
Radar Safety and Microwave Exposure
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In recent years, affordable prices and user-friendly systems have greatly increased the number of radar units in use on sailboats. But this surge in radar use has come with some risk of exposure to microwave radiation. Given the size of these sailboats, radar scanners are often mounted in close proximity to crew, or even to people on nearby docks or other boats. It is possible, although not probable, that these persons can be exposed to levels of microwave radiation that can exceed the recommended safe limits.
Microwaves (RF energy at radar frequencies) can be hazardous if the intensity is sufficiently high. Microwaves are absorbed by the water in living tissue and their energy is converted to heat that may easily damage some organs, particularly the eyes, which may develop cataracts. For safety, always avoid looking directly into a scanner whether the radar is transmitting or not. It is well known that microwaves will interfere with cardiac pacemakers and it is common place to see the warning signs in public areas where microwave ovens are in use.
It has also been shown that long-term exposure to low levels of microwave radiation can induce a variety of physiological effects in small laboratory animals. The importance of these effects and their relevance to humans are not yet fully understood. Again for safety reasons, you should avoid long-term exposure and radar units should be operated only when needed for navigation or safety. When the radar is not needed, it should either be in standby mode (not transmitting) or turned off.
Obviously, the radiation levels associated with marine radar units will vary according to the particular make and model. A radar unit of three kilowatts up to approximately 0.5 watts per centimeter squared, operating in the X-band at 3-1/2 feet from and at the same height as the scanner, can be encountered. OSHA has determined that the recommended maximum safe level of exposure to microwaves is 0.2 milliwatts per centimeter squared. The average intensity can be as high as 0.8 (milliwatts per centimeter squared) when the scanner is stationary. At a distance of 7 to 10 feet from the scanner, the average intensity drops to safe levels (i.e. below 0.2 mW/cm2).
At points above or below the scanner's horizontal plane, the radiation level is lower than that measured at a corresponding point on that plane. However, it must be noted that the average radar has a rather large vertical beam width (20 to 25 degrees) and microwave radiation is beamed about 10 to 12 degrees above and below the horizontal plane. At 5 feet from the scanner and 1-1/2 foot below the scanner, the average intensity can still be in excess of the OSHA safety limit.
For these reasons, the scanner should be mounted as high as possible. You should also ensure that the radar is not transmitting when crewmembers are aloft or working in the area of the scanner. Crewmembers should be briefed about the hazards of RF energy and instructed to avoid the scanner by a minimum horizontal distance of 6 feet and a vertical distance of 2 feet when the radar is operating. Crewmembers should be briefed to not remain within the hazardous area for prolonged periods.
During normal radar operation, the average exposure is reduced, because the scanner rotates and a person is exposed only when the beam sweeps past. For example, a person standing three feet away from a four-foot rotating scanner is exposed to less than 20 percent of the average radiation level of a stationary beam. Exposures to microwave radiation above the recommended safe limits are most likely to occur in the immediate vicinity of a transmitting scanner when it is stationary. When the scanner is rotating for normal radar operation, average exposure is below the recommended safe limits; even at points as close as 3 feet.
Some radar units are designed to prevent emission unless the scanner is rotating. Other models, however, lack this safety feature. In these cases some care is required on the part of the operator to prevent unnecessary exposure of crewmembers. Operating procedures should be adopted which ensure that no microwave radiation is emitted except when the scanner is rotating.
A good rule of thumb for all small marine radar units is that the equipment should be turned off when not required, particularly in areas of high population density (e.g. at dockside and when moored in the area of other boats).