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Old 08-05-2014, 03:18 PM   #1
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"Backwards" radar?

Greetings,
OK, so I've stepped my mast and will be making a cradle to hold it in place in a horizontal position in an effort to lower our air draft. Problem is, the mount the open array radar is on still sticks about 3' above the mast (2' above the next lowest part of the FB). Would it be possible to switch that mount to the back of the mast and still have the radar function when the mast is in the upright position? Meaning, when the radar is on, it will be "shooting" through the wooden mast (about 5"wide with the masthead light wire in the middle of the hollow mast). Any loss of definition/signal and how significant might that be?
Thanks in advance.
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Old 08-05-2014, 03:34 PM   #2
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So let me get this straight. When the mast is up, the radar will be mounted on the back side of the mast? If so, then any blind spot would be directly in the line of travel? Did you have a blind spot to the aft of the boat before? Then that's your answer.
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Old 08-05-2014, 05:05 PM   #3
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Not sure if it's a blind spot or just one of reduced definition. I really never notice a blind spot on the backside of my mast or the 6" box aluminum mast on the assistance towboat.

From a Garmin install manual...near page 4...it says obstructions "may" cause blind and shadow sectors.

http://static.garmincdn.com/pumac/12...structions.pdf

Because you are hrdly ever on a perfectly staright motionless course...good chance the target will show up even if you do have a blind sector...it will just be intermittent more than normal at far and closer ranges.
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Old 08-05-2014, 05:13 PM   #4
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Greetings,
Mr. R. Correct. Back side of the mast. Alas, I can't remember if I had a blind spot behind or not (Trust me, the memory isn't the FIRST thing to go). I'm going to have to take a few more measurements to see if my idea is viable at all.
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Old 08-05-2014, 05:21 PM   #5
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Quote:
Originally Posted by RT Firefly View Post
Greetings,
Mr. R. Correct. Back side of the mast. Alas, I can't remember if I had a blind spot behind or not (Trust me, the memory isn't the FIRST thing to go). I'm going to have to take a few more measurements to see if my idea is viable at all.
Can you put it off to one side and have something else (even if smaller in size and light weight) to help visually offset it?

May look better also than having it on the back of the mast.
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Old 08-05-2014, 07:15 PM   #6
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Can't rely here on readings from directly astern with radar. Mostly false readings.

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Old 08-05-2014, 09:32 PM   #7
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Or perhaps redesign the mounting bracket so it is clamped rather than bolted to the mast.
Then the clamp can be loosened and the radar assembly swivelled to the side when lowered.
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Old 08-05-2014, 10:28 PM   #8
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How about a hinged radar mount that could still hold the radar in its horizontal position when the mast is down and locks in the horizontal position when the mast is raised.....
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Old 08-05-2014, 10:42 PM   #9
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If the open array antenna is 5' across, then a mast ahead of it say 8" thick will obstruct just a small fraction of the beam and bounce.
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Old 08-05-2014, 10:47 PM   #10
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Can you move it to the top of the mast?
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Old 08-06-2014, 06:41 AM   #11
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What is the width of your radar antenna? A really small dome would suffer greatly but a 3' antenna, not so much. My old 18" Garmin dome had modest problems due to the 4" aluminum mast it was mounted to. My 24" Furno suffers almost no effect from the 2" stainless pipe mast behind it.

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