Recommendations for Cheap, Older, Basic Radar ?

[Aquah0lic]

While motoring my new boat down the Chesapeake bay last week, I ran through about 30 miles of fog that was thick enough to chew. Visability got as low as 100-200 ft and little fishing boats were popping out of the fog so close that emergency course changes barely saved me. During those 5 hours I decided a radar was a safety item.

It will likely only be used in times like those or rare night navigation. I'm looking for something small and cheap with minimal range(5-8 miles maybe) but decent sensitivity. Can anyone recommend a model or have such a model laying around from a refit for sale?

[donradcliffe]

There were several used radars in the consignment shop in Newport, but I didn't see any in Annapolis. Mine was a working Furuno 1800, which got sold for $10 at a charity auction, so there are some bargains out there somewhere. Did you try ebay??

[Aquah0lic]

I have looked on ebay, but I don't know the difference between a good one and a junk one. Also many that I saw had a 16 or 24nm range which is really more than I require. I'd rather have one that is real accurate out to 8nm since it is primarily for collision avoidance and I'm not going to hit something 20 miles away.

[Aquah0lic]

Don, when did you leave Annapolis? I left on Thursday, stopped at Solomons and Friday was the fog day. I ran into it crossing the Potomic mouth where I was sure any moment a giant freighter heading up the river was going to run over me without ever knowing it. Somehow made it to Deltaville(home port) in one piece that evening.

[Nauticatarcher]

Bought Simrad Anritsu 24 mile lcd screen on Ebay for $600 works great, stay clear of small JRC units

[Stillraining]

Originally Posted by Nauticatarcher

Bought Simrad Anritsu 24 mile lcd screen on Ebay for $600 works great, stay clear of small JRC units

So what shortcomings should I know about my JRC unit...Radar is all new to me and it came with the boat.

[Lancerbye]

If I was back home at my boat rather than the middle east You would be getting a good Icom radar with daylight screen for the cost of shipping. I placed one in the consignment store in Steveston just south of Vancouver, BC over a year ago. It is still there. I only changed it out because I wanted an LCD type which had a smaller screen and I was able to hang it from a ceiling position. It was still working good.

[RBEmerson]

I've got an R20X with all the trimmings (two displays [can only use one at a time] with fresh memory batteries, cables, mast mount, the original manual, even the correct Raytheon/KVH fluxgate heading sensor with docs). This is about as turnkey a package as anyone could hope for. Displays are in excellent condition (no burn-in, cabinets clean). The radome looks like it's been in the Chesapeake for about 8 years, with the usual sun wear, some minor wear from halyards, but no cracks, etc. I can wire the scanner back up long enough to take a couple of "proof of life" photos. The unit's at the house, about 30-40 miles NW of Philadelphia. The R20X came off to make room for an R70+ (adds MARPA support).

[Aquah0lic]

RBEmerson, HyLyte sent me your link from scca. Thanks, but $1000 is far more than I plan to spend. I'm sure it's worth it but not in my budget.

What I am really looking for in this thread is some of you guys that upgraded your systems 10-15 years ago so you could network, overlay, etc. and grudgingly removed a radar that you really liked in order to get these new features.

I would like to know the model of that radar so I can look for one on ebay.

Thanks.

[RBEmerson]

You've got private mail.

[dacust]

Originally Posted by Aquah0lic

... Also many that I saw had a 16 or 24nm range which is really more than I require. ...

FYI, the range listed is really the power. The range they quote is what you'd expect in totally clear air. As water in the air (fog, and especially rain) increases, the range drops. So, that 16-24nm range radar has the extra power so if you get in a serious blinding downpour, you may still have a 2-3 mile range. On the other hand, the size of the radome will determine the resolution: how small a target it will pick out. That's in general, of course. The more modern radars have software and other improvements that makes the resolution better on smaller radars that it used to be.

For my use (and sounds like yours, as well) I won't worry too much about how large the array is, but I'll get the most power I can get within my price range. I want a 4kw. Prefer a 24", but that's negotiable.

-dan

[Hampus]

Originally Posted by Stillraining

So what shortcomings should I know about my JRC unit...Radar is all new to me and it came with the boat.

You should excpect no shortcomings from your JRC. There is no reason for saying it's bad. JRC are huge in marine electronics, although 90% of their market is in Asia. Until 1996 Raytheon and JRC were one. If you open a Raytheon manufactured pre 1996 all you see are "JRC"-stanps. Are all Raytheon crap? A lot of other brands use JRC components like magnetrons and micro frontends. I've spent the past 9 years in the marine electronic business, two of those years working for a JRC dealer. I've installed and/or serviced I think most of the big names like JRC, Raytheon, Raymarine, Atlas, Terma, Furuno etc. and none is better than the other. They all have their pros and cons and they're all inovative in their own areas, but saying that JRC makes bad equipment really is unfounded. They might be a bit sluggish when it comes to installation and user friendlieness and they have no clue what the word "design" means, but if you just keep the water out of the equipment, same as the rest, it will keep going and going and do you good for many years.

/Hampus

[RBEmerson]

Originally Posted by dacust

FYI, the range listed is really the power. The range they quote is what you'd expect in totally clear air. As water in the air (fog, and especially rain) increases, the range drops. So, that 16-24nm range radar has the extra power so if you get in a serious blinding downpour, you may still have a 2-3 mile range. On the other hand, the size of the radome will determine the resolution: how small a target it will pick out. That's in general, of course. The more modern radars have software and other improvements that makes the resolution better on smaller radars that it used to be.
[...]

In a word, notquite. Power varies with range (although it doesn't have to) but selecting a range also adjusts the maximum time delay the radar will accept. Radar is really nothing more than a funky depth sounder that spins about 360 deg. and draws a dot for every bit of transmitted signal returned. The dot's distance from the center of the screen (i.e., ship's location) is determined by the time it took the signal to go out and come back.

Water and water vapor happen to reflect and attenuate x-band radar signals (those commonly seen with marine radars). As a result, trying to get a marine radar to "look" beyond a pocket of rain may not work (that is, even of there were a perfect radar reflector on the far side of the rain, very little signal will make it back to the antenna), but this is not a reduction in range! In fact, the same thing happens all the time with, for example, a ridge of sand dunes or small bluff along a shoreline. Whatever lies beyond the ridge or bluff is not seen on the radar because is lies in the radar shadow of the ridge or bluff. In the case of rain, it's the amount of water in the air that creates a shadow.

As to antenna size, plain and simple: size matters. x-band radar has a wave length of about 10 centimeters or loosely 5 inches. A smaller antenna (e.g., 18 to 24 inches [or loosely 3 to 5 wavelengths long) simply blurs together the wave fronts coming back from the targets; the receiver knows there's a signal present but can't resolve the angular data as well as a larger antenna. There are some signal processing techniques that can recover some of the lost angular data, but at the end of the day there's no escape from bigger is better.

Unfortunately, most marine radar makers sell the notion that bigger antennas must have bigger transmitters. While 24 and 48 mile radars are good for spotting precipitation, they don't do diddly for spotting a ship below the radar horizon, a ship that might be only 7-10 miles off. The beam goes out horizontally from the antenna, spreading somewhat as it goes, but basically what's beyond the radar's horizon and at sea level is in the earth's radar shadow, period. The rain, however, is conveniently above sea level and out of the earth's radar shadow. But anyone who thinks having a 48 or 72 mile radar means they'll see a freighter some 20-30 miles out is sadly misinformed.

ADDED:
+1 on JRC radars - JRC's name can be found in a number of Raymarine radars as well as Raytheon radars. They're often an OEM "foundry" for better known brands.

[captjcook]

I simply will have to have a JRC radar...how would my ego ever overcome that those are my initials? However, It is assumed by the CG in a collision situation if you have radar on board that it is/was on and being monitored at all times. Just a thought!
Jim

[RBEmerson]

A friend mounted a JRC radar on his boat for the same reason. As Jerry said, "why wouldn't I do it?"

Re: the USCG assuming the radar must be up and running, I've heard this several times but never from a Coastie. As far as I can figure out, the obligation is to maintain a suitable lookout, period. That is, if one is operating on a bright sunny day, with no restrictions to visibility (that is, no fog, haze, rain, etc.), and there's a collision, whether the radar was up and running won't matter quite so much as the give-way vessel's captain was, at the time, intent on watching "Mermaids Gone Wild" on the chartplotter's display and didn't see anything outside of the boat. OTOH, if it's the classic dark and stormy night, there's a collision, and the radar is colder than a well digger's elbow, it could be the makings of a very unhappy time.