Raydome Pedestal ???

[charlieft]

I'm getting ready to install an 18" Raymarine radar drum on the arch of my 260DA. I have noticed that some people use a ~6" to ~8" high pedestal and others just bolt the dome right down onto the arch or hard top.
For example ... the local harbor master has it bolted to his hard top (no pedestal) ... could this be because they usually stay around the harbor area?
What is the main purpose for the 6" added height? Do you recommend using a pedestal?

Thanks,
Charlie

 

[estebanj]

I think it's a matter of looks and clearance with other objects in the boat. This is from the Raymarine web site:

Mount the scanner as high as possible above the waterline for better long range performance, but make sure it:
• is above head height.
• is easily accessible.
• is as near to the boat’s centerline as possible.
• is on a rigid and stable platform.
• is clear of large objects such as the flybridge, large engine stacks,
searchlights, horns or masts.
• is clear of heat and fumes.
• is at least 1 m away from a magnetic compass or other equipment
antenna.

Don’t put the scanner so high, that it is affected by the pitching and rolling of the boat.

Esteban

 

[Sea Ray 300]

One other consideration is total height for over the road hauling.
Unfortunately, I have to remove my radar for hauling.

 

[AWBoater]

The pedestal has to do with two issues.

Many boats have "low" arches, which are not sufficent enough in height to get the radome high enough out of the way of occupants of the boat. You don't want even a 2KW (18") radome radiating the rear of your head.

Fortunately radar energy is beam-like, so there is little radiation even immediately above and below the dome.

The second reason is one of interference. If you have a GPS receiver/antenna unit, you want it either above or below the radome (beam). By putting the radome on a pedestal and the GPS antenna right down on the arch, you should have sufficient clearance between the two.

If the GPS is in the path of the radar, it could affect its reception.

And, yes, some do use a pedestal for looks, but that is not the intended purpose.

 

[osd9]

It's also a good idea to mount the radome, wether on a pedestal or not, at about a 3-5 degree angle...tilted foward. That way, when you are running on plane, the radome will be closer to level.

 

[bliss]

Another consideration -$$$$ - they're on Ebay all the time.