Mine is pole mounted - but I would have liked it be mounted on the mast. It needs to high so that it can see farther. I guess to find the best place to drill holes would be to find a mast mounted unit then see how theirs is done.

Why would using a split stay tensioner be a problem for mounting it on the back stay? On mine, it's mounted on the triangular bracket where the top, single stay is connected to the bottom double stays. I can't see how a tensioner would affect that. As for the pole: I wanted to mount it higher up, mainly because I didn't want to be subject to the radar rays. It was an easy process mounting it and I don't regret using this mount. There's even an outfit up in Washington that manufactures a swivel mount on a tensioned delrin bushing (rather than damping the swing by hydraulics) that is way cheap. It's the one I used.

Harold
You might pursue the mast mounting option if you were able to confirm the location of in-mast conduits from the mast manufacturer.

While there differences between your boat and my Mk11 furling mast, on mine there are 2 conduits at the front of the mast. One goes to the masthead and the other goes to a point just below the spreaders for the running and deck light cables and also for the radar cable as that's where mine is mounted.

Both of these conduits finish about 1 foot from the base of the mast.

If you could confirm the existence of the spreader conduit, you could locate it at the point where your light cables enter the mast at the spreaders.

In my opinion its a good location for the radar as its obviously higher and out of the way and doesn't need any other hardware nor interfere with the genoa.

Depending on the fitting on the end of the radar cable I don't think the conduit is large enough. I also read somewhere that about 16' above the water is the best location, much higher and you loose too much close in coverage. I think the spreaders are much higher than that. What the PO did on mine and I copied when i upgraded was to insert a big 12" zip tie into my unused spinnacker halyard exit keeping both ends outside the mast so you form a loop. The conduits are located at 2 and 10 oclock so you can drill a hole in the front of the mast. Feed the cable down the mast using a hook to fish it out of the base. When the cable is in the correct position, tighten the zip tie to hold the radar cable against the mast to prevent banging. I did mine with the mast off, but I don't see why you couldn't do the same thing with it installed.

Radar antenna mounting is sort of a blondes, brunettes, redheads decision. Everyone has their preferences for one reason or another, but all three locations (mast, stern pole, backstay) will work just fine. There are a few tradeoffs, but nothing serious.

Often the decision on where to mount depends on installation ease. I chose to place it on the mast, above the spreaders, and not on a gymbal, and I have been very pleased with the result. Of course I installed it when the boat was new and the mast had not yet been stepped, so that was an easy decision.

The vertical beam shape of a marine radar is very broad, so having the antenna that high up (mine is 30 ft off the water) doesn't compromise range close in. I have tried measuring the minimum range off the bow, but didn't have a long enough measuring tape at the time. I estimate my radar's minimum range at about 45 feet forward of the bow nav light, just a little more than one boat length; but I now have a longer measuring tape on board and intend to get a definitive answer at next opportunity.

Considering mast mount, be aware that routing the cable down the mast is only half your challenge. You also have to get the cable from the mast base to the helm. I chose to route the cable along the stbd side - unlike John's choice of portside, as he notes below. It was this challenge that caused me to *cut* the thick analog cable to make my life simpler. One should "never" cut the cable, they say, but I invented a method of doing that that recaptures the integrity of the original.

As for "stable in rough seas for proper performance", well, it doesn't matter where you mount it for that because the boat isn't stable in rough seas. All three locations will serve equally well, or equally poorly. Not only are you dealing with a violent motion, you're dealing with severe sea clutter.

One thing you should never compromise is radiation safety. Magnetron radars pump out 2 kilowatts or more (incidentally, 2kw is entirely satisfactory on our boats...there is NO NEED to waste money on a 4 kw radar for a Catalina 36), which is a high power level that has two risks. One effect is tissue heating...the potential for damaging surface skin tissue, resulting in, as an example, early onset of cataracts. The other effect is potential genetic, ie molecular, damage that might trigger cancer or other serious problems such as damage to a fetus if a pregnant woman were exposed to the high energy radiation.

There's a new technology on the market euphemistically called "HD radar". The HD label is a marketing term that has no real value, so ignore the term. But the radar uses very low power, less than 1 watt I believe, and so would present no radiation hazard. I like the concept for that, and also because it's time someone drove a stake through the heart of the last remaining vacuum tube onboard (the magnetron is a vacuum tube...remember those???). But low power radar has one serious drawback: it won't trigger a RACON.

[url]www.starpath.com[/url] offers an excellent online radar course, but then I am biased...I am the instructor.

I was in the same situation 2 years ago and after lots of thought went with a mast mounted Radome. The pole is handy for other uses besides Radar but potentially it puts you in the beam once you are half way along the deck. Although everyone says its quite safe, we were still uncomfortable with the thought. We discounted the back stay mounting for a similar reason.
We purchased our mast mount from Kato Marine and have been very happy with as it is rock solid. We mounted it just below the spreaders as we felt that was a better balance to reduce surface clutter/echoes when underway. Ours was analog which has thick cable, usually the cable that comes with the kit is too short and you will need a longer one if you run it all the way aft to the helm. Because of the analog cable, we swapped out one of the existing mast conduits so we could accommodate the cable. If it is a digital radar, you can probably get away with the existing mast conduit as the cable is quite thin. In our case, we had just moved Hilbre from Lake Mead to San Pedro so the boat was in the yard with the mast down, making an easy installation. We ran the cable along the port side of the boat and found very little issue in doing so. (Mkll 2003)
We have been happy with our decision and the Radar works well with good coverage and no issues due to heel. Hope this helps.
John Meyer
Hilbre 2135 San Pedro, CA

A quote from Raymarine:

[B][I]"Mount the scanner as high as possible above the waterline for better long range performance"[/I][/B]

A standard 18" radome mounted on a mast, 25' above the water, will actually have the beam HIT the water at roughly 72 feet from the dome. If your mast is set back 12' from the bow of the boat this means that a mast mounted dome can see targets at 0' above the water water 60' off the bow of your boat. Now add a seven foot boat height, for a typical Sea Ray, and you can see it 42 feet off your bow. The close in argument is not even an argument. If you need to see stuff on radar 42 feet from your bow then you are in some serious trouble.

In contrast a 36 foot boat with a stern pole at 12 feet high could actually get a return from the bow pulpit. Again if you have something 6" off your bow that you NEED to see then you just have not done your job tracking targets.

I have had radar mounted on the mast, a Questus back stay mount on my C-36, and currently have a pole. I currently have it on a pole and HATE IT for performance reasons. Even when I had it on the mast, on three other boats I've owned, I could pick up my boat neighbors in the mooring field with no problems and close target acquisition was a non-issue.

Even in Maine, where fog was invented, I have yet to find more than 4 or so days out of the last 20+ years where the visibility was less than 75 feet. If you have not acquired a target by the time it gets that close you're just not doing your job.

As someone who has spent literally thousands of hours operating radar in the fog, as both a commercial fisherman and a pleasure boater, there is no question that a mast mount, 22-25 feet up, would be my preferred placement. Eventually I will remove my pole and place my dome on the mast but the boat came this way and the radar pole has been painted around with Awlgrip.

I clench my teeth every time I am in 6+ foot swells, and fog, and keep loosing targets and having to re-acquire them due to the low dome height when in a trough. I rarely if ever had this problem with domes mounted on the mast. With a 12' dome and a 20' tall target you can see it at 9.52 miles. If that target is 30 feet tall you can see it at 10.73 miles. A 90' high target can be seen at 15.54 miles. Of course if you are in 10 foot swells or seas every time you hit the trough your dome height becomes essentially 2' not 12'. If the other boat goes in a trough at the same time you may loose a target and have to re-acquire it at the top of a wave/swell...

If you only sail in protected foggy bays with no swell or chance of a sea a pole mount can suffice but if you venture into the open ocean, at night, or in the fog, or in heavy seas, a higher dome placement will track and keep targets on the screen far better.

So in summary I'd still opt for mounting the dome on the mast..:)

Agreed, and therefore my preference for the mast mount. My preference is for blondes, too, but then I am [required to be] biased there, too.

I suggest keeping the bottom of the radar scanner a few inches above the spreaders. You'll want to avoid placing the scanner at the same height as the spreaders because the metal spreaders will divert the beam and cause all kinds of problems. The second concern is to make sure your radar reflector is not at the same height as the scanner. I think my mount is an Edson, but I'm not sure I am remembering accurately.

My radar location is shown in photo below.

Harold,
If you need a 1-1/8" hole for the end fittings, you can forget about the conduit. I'm pretty sure the conduit is about a 1" OD. Use groups of three wire ties on the cable, oriented at 12, 4, and 8 o'clock, and spaced about 2' apart. Leave the tails on. They will keep the cable centered in the mast, and not interfere with the halyards. I've attached a picture of the Kato mount on Julandra. Mounted just below the spreaders, where Gerry Douglas suggested. Drilled and tapped for 1/2-20 bolts. It is SUPER strong. I could literally hang on it and it wouldn't budge. There should be a 2" hole near the base of the mast, port side. If you pull the stick, you can easily use that hole. If you don't it is really hard to reach. I installed my radar with the mast up. Used an extension ladder lashed on the foredeck. Lot easier than a bosun's chair. I drilled a 2" hole thru the seat riser just behind the mast, then a 1" hole thru the aft side of the mast. It took some colorful language, but I was able to get a messenger line from the hole in the mast behind the mount, down to the base, and then pulled the cable up, attaching wire ties as it went up. Hope this helps.

PLEASE DO NOT drill a 1 1/8" hole in your mast. Cut the data cable and re-terminate it. I use a special crimp tool for that data cable but a small terminal strip works too. I have installed many Garmin data cables that had to be cut and they will work just fine. It will need to be cut if you ever want to un-step your mast anyway..