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Old 25-02-2016, 12:31   #1
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Radar mounted under Solar

Howdy Folks,

As I posted in another thread, we're currently working through adding an arch that will hold 3 large (250-300w) panels and our wind gen.

We've been going back and forth on where to locate our radar (B&G 4G) either on the arch or on the mast. Our goal is to minimize shading of the panels and we noticed a boat in our marina with a somewhat unique setup. They had they radar mounted under the solar panels (maybe 6-8 inches) and claimed they hadn't noticed any impact to radar performance.

This caught my attention and I was just curious if anyone has tried this and how well it works. Since we're not concerned with tracking birds/planes and the radar would be mount ~12 ft above the waterline, how would you expect this to perform?
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Old 25-02-2016, 12:54   #2
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Re: Radar mounted under Solar

I'd call B&G and ask, never thought about it myself.
I don't see truly why it would matter, panels would block side lobes, but they would do that with the Radar above too, so?

Might hurt storm cell detection, which has so far been the best use of Radar for me
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Old 25-02-2016, 13:10   #3
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Re: Radar mounted under Solar

Erb, as it happens, when we bought this boat, it had just that setup, with a Furuno 1720 mounted just under 2x80's and 2x40's. I found that it did indeed impact the radar performance... pretty severely. When heeled more than a few degrees, the "view" to leeward was badly attenuated, with the obscured field growing angularly as heel increased. This was easily observed when in a uniform rain field, for there was a fan-shaped area with no return, whilst all other directions showed the expected clutter.

I did not like this at all! Oh, the other thing was that this low mount made a potential exposure of a standing helmsman's head to the microwave radiation from the radar. I wasn't too worried, for the manual had some exposure recommendations and the distance was adequate according to them, and no one would have normally been standing behind the helmsman with the radar running, but some folks get really upset about such things.

So, my definite thought is to not replicate the setup. When we replaced that radar, the new one went on the mast where I believe one gets the best trade-off in performance.

Jim
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Old 25-02-2016, 13:29   #4
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Re: Radar mounted under Solar

Thanks Jim, always good to get some first hand real world feedback. I just called B&G and they seemed a bit dubious as well.

We'll likely stick with the original plan to mount it on the mast, was just hoping for a simple fix...you'd think I'd know better at this point.
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Old 26-02-2016, 09:17   #5
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Re: Radar mounted under Solar

Not sure height is so much of a problem, lots of boats have radar mount reletivly low down (motor boats?) I find radar is most useful for 5-6 m range. Can you mount the panels so the angle fro the panel to the radar is 30deg to clear the beam?
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Old 26-02-2016, 09:30   #6
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Re: Radar mounted under Solar

Quote:
Originally Posted by ErBrown View Post
Howdy Folks,

As I posted in another thread, we're currently working through adding an arch that will hold 3 large (250-300w) panels and our wind gen.

We've been going back and forth on where to locate our radar (B&G 4G) either on the arch or on the mast. Our goal is to minimize shading of the panels and we noticed a boat in our marina with a somewhat unique setup. They had they radar mounted under the solar panels (maybe 6-8 inches) and claimed they hadn't noticed any impact to radar performance.

This caught my attention and I was just curious if anyone has tried this and how well it works. Since we're not concerned with tracking birds/planes and the radar would be mount ~12 ft above the waterline, how would you expect this to perform?
Make sure it isn't low enough to fry your brains with Microwave radiation.
Dangerous in my prospective for what its worth. I am a Toxicologist
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Old 26-02-2016, 09:32   #7
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Re: Radar mounted under Solar

interesting thoughts... my new B&G 4K radar is looking for a mounting location. It's either up the mast or ... off the back of the solar / davit arch. I'm thinking that mounting it behind the panels and just high enough to clear won't shade the panels and will be sufficient for coverage.
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Old 26-02-2016, 09:37   #8
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Re: Radar mounted under Solar

Placing the radar under the solar array isn't a good idea. The array will distort the antenna emissions of the radar, affecting it's directional precision and overall signal intensity, for both outbound and inbound signals. It may also expose people on the boat high microwave radiation levels, with bad consequences, especially human eyes and creation of cancers. The radar antennas on boats are kept high and away from humans for these reasons. BTW, the shielding of a home microwave is an essential human health matter. Don't mess with that, either.
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Old 26-02-2016, 09:55   #9
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Re: Radar mounted under Solar

Radar should be placed as high as possible, away from all obstructions and other electrical devices. Upper main mast or on a pole at the stern preferable. You really do not want stuff around it that may absorb/dampen/interfere with the return. So, not a good idea.
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Old 26-02-2016, 15:50   #10
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Re: Radar mounted under Solar

Hi

I'll add my two cents worth. We are junk rigged and therefore cannot mount it on the mast. We originally had the radar ahead of the main mast under the sail's lowest batten ahead of the pilot house and about 8 feet above the deck. Mounted on a 'granny bar'.

When we added an arch aft to help deflect the sheet and sheetlets on a gybe we also added more solar panels of course (-: and to not shade them put the radar under them.

In that position it is six feet above the deck. We have seen no problems with timely detecting
Squalls and the radar even detects bamboo FADS common here in Thailand and Malaysia.

It is a broadband radar which according to Simrad emits less than a phone! Because of its low power consumption it is on all the time at night no matter the weather or location. On a recent passage from India to Langkawi it was great to aid timely reefing for Squalls as well of course for seeing the positions of ships in conjunction with the Vesper AIS. We seldom use it on its maximum range.

We love it!

Jim and Helen sv GAIA
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Old 26-02-2016, 18:39   #11
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Re: Radar mounted under Solar

Quote:
Originally Posted by ErBrown View Post
Howdy Folks,

As I posted in another thread, we're currently working through adding an arch that will hold 3 large (250-300w) panels and our wind gen.

We've been going back and forth on where to locate our radar (B&G 4G) either on the arch or on the mast. Our goal is to minimize shading of the panels and we noticed a boat in our marina with a somewhat unique setup. They had they radar mounted under the solar panels (maybe 6-8 inches) and claimed they hadn't noticed any impact to radar performance.
This caught my attention and I was just curious if anyone has tried this and how well it works. Since we're not concerned with tracking birds/planes and the radar would be mount ~12 ft above the waterline, how would you expect this to perform?
I did that as a temporary solution before moving my radar to the mast, but found no problems at all.
I should add that we have a trimaran which never heels more than 5 degrees under normal sailing.
Ten degrees, it's time to reef !

It sure beats most installations of solar panels when people install wind generators, radar, GPS and other antennas ABOVE THEM.
Last summer I saw (at anchor) a very expensive looking black hulled 60+ foot sailboat with around 500 watts of solar with all the above installed ABOVE the panels. (He was reading a book in the cockpit while running a generator)

They just don't think before they do that, and then they complain that "solar doesn't work". Well, Duh...

Brain, eye functions? Who, where, Brain functions? Who where, brain functions, who where. Brain functions, who where?
Did I mention brain functions, oh also, eye functions let me put on my coke bottle glasses...
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Old 29-02-2016, 22:08   #12
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Re: Radar mounted under Solar

It's time to break out the trigonometry. The B&G 4G installation instructions are pretty clear on the cone angle and recommendations for installation on a hardtop. You need just reverse the calculations for an upper obstruction such as your solar panels.
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Old 01-03-2016, 05:26   #13
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Re: Radar mounted under Solar

Greetings and welcome aboard the CF, Lefty.
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