Radar - melted radome?

Ron on Meander · Posted: Sun Mar 23, 2008 9:20 pm Post subject: Radar - melted radome?

Can any of you radar experts tell me if its at all possible for the radar to melt its plastic dome? I was working on the boat today and I noticed that the plastic radar dome on my Garmin GMR18 looked a little lop sided. I climbed up and to a look. The dome on the top is actually melted and distorted. In fact in one place the plastic has melted completely and there is a hole about 1/4 inch or so through the plastic. This is just on the top of the dome. The sides are fine. Is there any possibility that the radar can put out too much energy and melt the plastic? Sounds kind of far fetched to me but I can't figure out how else the dome could melt.
Any thoughts?
Thanks
Ron

Sneaks · Posted: Sun Mar 23, 2008 9:26 pm Post subject:

Way far fetched for the radar transmitter to do it. Melting takes energy and your entire radar only uses about 28 watts. Interesting problem. If it happened to me I'd be taking closeup digital pictures and sending them to Garmin....

Don

IT-SEA-BIT-C · Guest

you have my attention , go to let us know that happend , when you find out . didn't just pull the shrink wrap off did you / mabey guy with propane gun got a little too close ?

Ron on Meander · Posted: Sun Mar 23, 2008 9:59 pm Post subject:

I'll post some pictures tomorrow as I don't have my camera at the moment. It certainly is strange. Sneaks, thanks for the info on the output power. I did not think the radar itself would do it, but I'm at a loss as to how it happened. Lightning? Nah, we live in Vancouver and don't get lightning in the winter. Too close to a power line? Nope. It-C-Bit-C Propane torch? Not unless some crazy was running around the neighbour hood looking to radomes to melt.We have our share of crazies up here, but that is even too much for Vancouver. I wish I had the pictures to post. They will show how weird this is.

thataway · Posted: Sun Mar 23, 2008 10:00 pm Post subject:

Not the radar beam. Something hot has gotten in on the top of the radar dome. Is there sign of melting on the inside of the dome? Does the radar work properly?

journey on · Posted: Sun Mar 23, 2008 10:59 pm Post subject:

In my experience with radomes, there is nothing internally near the top of the radome. Clearly the rotating antenna is below the top and not connected, and the electronics are at the bottom of the radome. So there must have been a decent hot spot/short inside, or something hot landed on the radome.

One could lift the radome cover off, and look inside to see if anything is burned internally, especially under the hole. If you can't see anything inside that is burned, or internal smoke on the radome, the the heat had to come from the outside. There should only be 4 screws holding the plastic cover down, so it's easy to remove and have a peek inside.

Boris

Ron on Meander · Posted: Mon Mar 24, 2008 11:57 am Post subject:

Thanks for the replies guys. I was pretty sure that the radar itself couldn't do it. I'm going to go down to the shop that did some warranty work on the boat before christmas and check to see if they might have something "hot" up high. I'll let you know what I find.
Thanks again.
Ron

Ron on Meander · Posted: Thu Mar 27, 2008 11:42 pm Post subject:

Well I know now what caused the radar dome to melt.

This is what the dome looked like from the ground. Couldn't really see anything out of the ordinary.

This is what it looked like at eye level.

And this is what it looked like when I got up high enough to see the top. The dome is melted and warped and there is a hole melted through the plastic about the middle of the dome.
What happened is, just before Christmas I had the boat in at the dealer for some warranty work. Because it was fairly cold they had the boat stored inside the shop for a few days. Well no one noticed that the overhead radiant heating was close to the radar and of course was on because of the cold temps.
The dealer Galleon Marine, was excellent about it, when I told them what happened. They just replaced the radar, no questions. I was impressed how quickly they did it. Same day that I took the old melted unit in, they replaced it with a brand new one. Cudo's to them. Beer

RJD Wannabe · Posted: Fri Mar 28, 2008 12:04 am Post subject:

amazing, good detective work, outstanding dealer!!

IT-SEA-BIT-C · Guest

Glad to hear it worked out for you it was an accident am very happy they did the right thing to resolve it with no bull s--t . I was asking alot of people what could have caused it for you but no one i knew could figure it out either . i was kinda close though , about an outside source melying it . kid at a boatyard melted the heck out of my gelcoat 2 years ago with the propane gun and i didn't find it untill i removed the shrink wrap . but when i went back to the yard in the spring they tried to deny it , what a pain it was , had to repair it myself. any way happy to hear it worked out good for ya........ john