Radar causing interference with other electronics?

oldgrowth

I plan on mounting my radar about 12” above the front part of my cabin. My radio is on the top shelf in my cabin, about 18” under the radar. My VHF antenna is on the back side of my cabin about 27” from the radar. The GPS/monitor is mounted under the top shelf.

The instructions for the radar says keep the radar dome three feet away from all these objects. The cabin on a 16 is not big enough, so my question to those of you with radar is;
Do any of you have any of these objects closer than three feet and if so, have you had any trouble?
________
Dave

Dreamer · Posted: Wed May 09, 2007 1:40 am Post subject:

Dave,

I have a vhf antenna on either side of a 4kw Raymarine Radar, also a gps and tv ant. on the same arch. The only interference I get is a faint click in the radio from the transducer for the depth sounder. I wouldn't worry about it.

Wayne McCown · Posted: Wed May 09, 2007 10:36 am Post subject:

My radar dome and the GPS receiver are both mounted towards the front of the cabin, the radar dome in the center and the GPS receiver on the hand rail.

They are probably less than 2' apart. I experience no inference between them.

oldgrowth · Posted: Wed May 09, 2007 12:52 pm Post subject:

Thanks, Roger, Wayne and (Bob Heselberg for sending me photos of his instillation). I will go ahead and mount the radar as planned.

The radar is the new 18” Garmin that just came out in April of this year, and it will overlay on my GPS/Chart Plotter. I think the 18” dome will look better on the 16/18 foot C-Dory than a 24” dome.
________
Dave

Jazzmanic · Posted: Wed May 09, 2007 1:34 pm Post subject:

Yeah Dave, I've been eyeing those new Garmin Radomes, very nice. I look forward to seeing your installation as I'll be doing the same sometime in the near future.

Peter

Larry Q · Posted: Wed May 09, 2007 7:03 pm Post subject:

Dave-
I have two antennas, furno radar dome and the GPS receiver all mounted within the width of the boat on the radar arch. I've not had any noise or interference except from the admiral when I do something crazy.

rogerbum · Posted: Wed May 09, 2007 7:08 pm Post subject:

mikeporterinmd · Posted: Wed May 09, 2007 9:21 pm Post subject:

I would do a test layout first. Route the cables through the cabin windows
or something and get a general idea. Test all VHF frequences on receive.
I've had more problems with head units emitting RF that cause the VHF
to become unusable than the other way. Once you start drilling holes, it's
much harder to change your mind! Also, if it turns out the unit emits
large amounts of noise, you may be able to return it more easily than if
you've routed the cables and mounted everything.

Also: don't forget to do a test receive for the weather channels that
broadcast in your area.

Mike

thataway · Posted: Wed May 09, 2007 9:24 pm Post subject:

I have two VHF antennas and two GPS antennas on the roof of the Tom Cat 255, with no interference from the Radar--these are all less than 3 feet from the radar. However, you want to be sure that the GPS antennas are not in the direct beam of the Radar--consider that the Radar has a 30 degree horizontal beam. You should be fine with the height of the dome.

The reason for a larger dome is that you will get better descrimination between objects. If the price difference was not much, I would go for the 24" dome. I would rather have a better descrimination than worry about the cosmetics of the size of the radar dome. The new Garmin gear seems great. I'll be very interested to see how the radar works.

oldgrowth · Posted: Fri May 11, 2007 12:47 am Post subject:

Peter – when I see you at Bellingham, I will let you know how it works.

Larry – thanks for that information. If you put in at Olympia for the Bellingham CBGT, maybe we can compare the radar units on the way there.

Mike – your information is always spot on and it could be foolish not to follow it, but I am a gambler. I will probably do a permanent mount of my hardware because it takes too much energy to do a temporary install then come back and do a permanent install. I will try and use some common sense in the installation process.

Bob – I have no way of comparing this unit with another because I have never had a radar unit. If Larry Q runs to BH with me, then maybe we can get some comparison of the two radars.
________
Dave

thataway · Posted: Fri May 11, 2007 12:35 pm Post subject:

The longer the radar scanner (radiator of microwave energy), the better the unit can descriminate between two objects. For example the Garmin 18" dome has a horizontal beam of 5.2 degrees and the 24" unit has a beam of 3.6 degrees The descrimination (ability to see close objects and to some degree the resolution of objects is almost twice in the 24" dome than the 18" dome. I always go for the largest dome which I can find. If you want better discrimination--and for instance to see birds for fishing, you might consider a 36" or 48" open array--and Yes, I have seen 18 foot fishing boats with a 48" radar open array....a bit much, I'll admit.