Can anchor mast light effect radar performance?

[danmarsh50]

Just purchased a used 2001 310DA. The anchor/nav. light is mounted directly in front (forward) of the closed dome radar. On sea trial I noticed they had the light mast folded down (horizontal not vertical). Looking around the marina I noticed most radar installations with anchor lights mounted on brackets aft of the radar arch. Should I be concerned with radar interference/performance with mast mount forward (directly in front of) of radar dome. Thanks in advance.

 

[shinsr]

As that is the factory mount position (in front of radar) I dont think its an issue - I have it there with my open array and have no issue whatsoever.

 

[sbw1]

Your radar will look right through the mast light and it will not be visible on your screen.

 

[Presentation]

Items like an anchor light mast may cause “Shadow sectors" or "False Echoes” if you have the gain adjusted to manual and have it set too high.


Please read page 16 & 17 at the below link.

The entire link below has great information but what you are concerned about is described on page 16 & 17.


http://www.furunousa.com/ProductDocuments/1622 Operator's Manual vj2.pdf

 

[Henry Boyd]

In general the answer is that the light mast will have no effect. The reason as explained in the RADAR class I took is that RADAR is a 'talk' and then 'listen' system with each mode being exclusive, i.e. it can't hear while talking and vice versa.

As a result close up objects don't get seen because the reflection comes back to the antenna while the system is still talking. Additionally, the antenna is spinning and may also be pointed away from the reflection. As you might guess the distance that things are invisible is going to be different for each model of RADAR as all that stuff varies by type and manufacturer.

The newer 'broadband' RADAR operates in a different way from traditional RADAR and I just don't know enough to say what the case is with those.

Henry

 

[sbw1]

Items like an anchor light mast may cause “Shadow sectors" or "False Echoes” if you have the gain adjusted to manual and have it set too high.


Please read page 16 & 17 at the below link.

The entire link below has great information but what you are concerned about is described on page 16 & 17.


http://www.furunousa.com/ProductDocuments/1622 Operator's Manual vj2.pdf

I read the Furuno manual and essentially it says that objects within a certain distance of the magnatron will be invisible. The light is clearly within that invisible zone. My mast lights and the other antennas on my hardtop do not visualize on my radar screen.

 

[Presentation]

I read the Furuno manual and essentially it says that objects within a certain distance of the magnatron will be invisible. The light is clearly within that invisible zone. My mast lights and the other antennas on my hardtop do not visualize on my radar screen.

You are correct; you will not see the mast.

What can happen is this:

Shadow sectors – the mast make a small sliver of area not visible. Objects behind the mast are not visisble on the radar.

False Echoes – the microwave comes out of the radar dome, gets to its target, bounces off the target, comes back to the mast, bounces off the mast and goes back into the radar.

This other target now has two images on your screen, the true image and a lighter false echo.

To observe this, head to open water, set your range so you have one object visible. Let’s set the range to ½ mile with a object ¼ mile away like a navigational marker. Now turn your gain to manual, increase your gain well beyond normal. You will see the navigational marker as a target or blip and also see a second smaller false echo where there is no object in the water. You may even see two false echo targets, one on each side of the real target.

Go try it and you will see what I mean.