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Ben E

Simrad 4G radar offshore performances issues?

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The following comments were first posted on a Panbo entry about the Vestas Volvo race boat wreck and grounding alarms but whereas we got pretty far off track I've moved all but the first one to here. Hopefully this will also mean that folks searching for 4G performance information will find this forum post, and I'm really hoping that sailors who've used 4G a lot offshore will report in.

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I have doubts that any radar and particularly 4G mounted low on the boat, like on a post or arch at the stern, about 12ft from the water, would have clearly painted a reef and surf line. My experience with such a radar setup in open ocean waters even in fairly nice conditions was disappointing. I put this down to:
- the motion of the boat
- the antenna at 12ft height vanishing completely in the troughs of some of the larger seas
- my Scanstrut self leveling mount overswinging significantly. It should have much stronger damping IMO. I would no longer dare to put a unit like this up on the mast where the motion is much stronger again.
I think it is these three effects that work together to make real targets vanish and pop up again and make them jump around and this is then compounded by lots of false echoes from sea returns. The target filtering of the radar display and my own "filtering" when looking at the screen then blend out (discount) the real targets, even a container ship at 6nm.
When motoring in calm seas that same radar clearly showed the volcanic island of La Palma at 28nm range but then there was no real risk of us hitting that island. When there was a real risk, on passage from the Azores to England, I had to rely on AIS, especially at night when eyeball visibility was low in fog or drizzle. This is in spite of me spending many hours playing with the settings.
The radar alarm was unusable because of constant nuisance triggering or else, with the sensitivity down enough to avoid nuisance triggering, the radar would be basically blind.
In situations like what Vestas Wind had when approaching the reef, I think one would need the antenna way up at the mast and maybe a powerful magnetron.

Posted by: Henning at December 13, 2014 5:42 PM | Reply

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Am I correct to say. The 3G/4G radar is great radar for inland cruising and low speed sailing but when you are sailing offshore or motor boating on high speed you do need a serious old school high current radar.this because of the range issue ?

Posted by: tcy at December 15, 2014 2:47 AM | Reply

I don't think that's correct, tcy, and certainly not definite. As I've written before I think there's something wrong with Henning's 4G radar, as the performance doesn't seem related to what I'm seeing with about the same antenna height.

Posted by: Ben in reply to tcy at December 15, 2014 8:01 AM | Reply

What should be wrong with my radar? La Palma showed perfectly at more than 28nm and in the large marina where we are now in Hamburg, I have spectacular performance and can tell which one of the 200+ slips is empty and which is filled. You shouldn't but probably could safely dock the boat from below at the nav station.
I chose this radar for its close range performance and for that you need to mount it low or else the 25 degree horizontal opening angle of the beam (12.5 up and 12.5 down) will look clear over everything you would want to see. I sometimes see BR radars mounted above the first spreader and wonder why the owners chose this combination of radar and position. But while the low position helps close range, I feel that it is a serious impediment in large swell because of all the false echoes that hide the real targets.
I can't say that you would need a "serious" magnetron radar for long range because I haven't tried it. The only comparative test of current production leisure boat radars I know of is Ben's and he says it compared OK to magnetron radars. But I did hear from other Atlantic sailors that I probably wouldn't be able to use the radar alarm with a low mounting position which turned out true.
Maybe Ben would care to take Gizmo out into the Gulf Stream in a northerly winter gale. 16 foot seas, tide against current and all, and let us know the results ;-)
However, if someone asked me for a recommendation for an ocean crossing watchkeeping and weather radar, I don't think I would recommend the 4G.
And yes, if you do these passages, you do want a radar.

Posted by: Henning at December 15, 2014 4:33 PM | Reply

I don't know what's wrong with your 4G, Henning, but here's what you wrote on another thread ( http://goo.gl/0doFx ): "...when crossing from the Azores to England, I could reliably see large container ships at only 2 to 4nm while I could see the same ships on AIS at up to 90nm." That's terrible radar performance almost regardless of sea conditions, and not what I've seen from 4G. It's true that I haven't had Gizmo out in truly big seas, and don't plan to, but I can report that in 3-4 footers with whitecaps, the 4G seems to handle sea clutter about as well as the 3 other test radars, all of which are 4-5 feet higher.

Posted by: Ben in reply to Henning at December 15, 2014 4:54 PM | Reply

Henning has doubts that any radar would have clearly painted a reef and surf line. I have doubts too, but for a different reason. Everybody regards returns from waves as noise, so they are deliberately suppressed as much as possible. We know that radar can see waves and boat wakes, although it does depend on the wave shape.

With shipping using AIS, what exactly are you watching for on radar on a passage? Radar is not currently smart enough -- blips come and go, where is the feature that determines which are real and tracks them, a more advanced MARPA which doesn't just drop a target if it misses a few scans. A radar where you can change the range and the blips on the screen (which are real targets) do not disappear into a dust speck sized pixel or two.
Posted by: norse in reply to Henning at December 16, 2014 3:02 AM | Reply

Norse: I think the reasons for your and my doubts are the same. Maybe I wasn't clear about "reliably see a container ship". I don't mean that the ship gives no return but that all the wavecrests around me give returns, too, and all these false return obscure the container ship until it's as close as about 4nm. Before that, the ship's return keeps vanishing when I (not the ship) am in a wave trough and so looks and behaves just like all the other false returns. I tried everything with gain and the other settings but there was no setting that would suppress the sea echoes while not suppressing the container ship.
Remember we are in the open ocean here. When we left the English channel near the beginning of our trip I was in awe for hours about the size of the rollers that had come from some distant place like Newfoundland and were traveling at a stately speed for thousands of miles. For the most part, they were completely benign. It's like a rolling hillside. You feel an urge to ski down them (which I did sometimes in our planing dinghy). Sometimes we motored in dead calm and when I closed my eyes I could feel being lifted and set down like in an elevator for one or two stories. The west side of La Palma, in place called Tazacorte, is where they make contact with land. They have a monumental breakwater there, 15 metres high, with 10s of thousands of tons of concrete. The first one they built turned out too small and the second one had cost EUR 53 million in EU grant money. This is to protect a couple of pleasure- and tour boats worth maybe 2 million in total...
I guess even a 48kw magnetron radar will show zip useable returns if hidden completely in a wave trough.
I conclude that for these applications the radar must be up in the mast (and it probably wouldn't hurt if it were really powerful). This should significantly reduce the amount of false echoes from seas and at the same time give consistent returns for real targets so they stand out better.
This is the complete opposite of my experience years earlier in the Kiel Canal when my old 2kw magnetron radar that came with the boat and was mounted above the first spreader failed to show the banks of the canal because it was looking over it and instead showed me farmhouses and outhouses a good distance from the canal. My conclusion then was that I really needed a radar with good close range performance and it needed to be mounted low.
Doh!
It seems that I need two radars... Only I fear that people will laugh their butts off when they see my boat. RODL - rolling on the dock laughing.
Ben, do you have some relevant experience with this?

Posted by: Henning at December 16, 2014 4:11 AM | Reply

I think Henning confirms my thought. 4G radar is great inland but out of the green into blue you do need some power. it's great to see the harber overlay and the mooring poles but on the ocean or north sea you also would like to see further ahead.

Posted by: tcy at December 16, 2014 5:36 PM | Reply

There are many bluewater boats using 4G. What Henning is describing now are pretty extreme conditions that will probably affect the performance of any radar not mounted way high. I've sailed from the Canaries to the Caribbean and many times from there to New England, but I've only seen swells like "rolling hillsides" once. I didn't have a radar at the time but wouldn't be surprised if one at 12 feet had trouble.

What I don't understand is why his 4G wasn't performing better when his boat was at the top of those hills. I've run 4G side by side with the best competing radomes for several years and don't think there's a big difference at 4 miles.

Posted by: Ben at December 16, 2014 6:18 PM | Reply

tcy: Your thoughts are yours of course but what I said was that I conclude from my not exactly extensive open ocean experience that you would want your "watchkeeping" radar mounted high to:
1. reduce the amount of false returns from seas ("sea clutter")
2. make real targets paint more consistently, at every or nearly every sweep
There are two different types of seas, wind sea and swell. NOAA wave models (at least the one ZyGrib uses) even have independent data for both (separate values for period, direction and height).
The wind sea is what bounces your boat around, gives you seasickness, causes a big pot of spaghetti to come off the hob even with the potholders in place (a huge mess in the bilge) and causes the toilet lid to slam shut before you have a chance to turn around and sit down (I need a bungee cord here). It also puts a strain on the self leveling radar mount so that it probably hurts more than it helps.
Swell is completely benign and gives you no more discomfort than an elevator. There is hardly any rolling of the boat associated with it. You can leave a glass of water on the cockpit table in 4m/12ft swell. It's safe to dinghy about in it. You can hear the outboard strain when you're going uphill and rev up when you slide down a slope.
Swell and wind sea are often overlaid. Then you can no longer feel or see the swell but it's still there, lifting you up and down and blinding your low mounted radar in the troughs.
I have never seen and will do everything I can to avoid ever seeing a 4 or 5m wind sea. On our 6000nm sabbatical we were able to completely avoid this which makes me believe or hope that it can be avoided pretty reliably.
But you can't really avoid the swell (and why would you?). You would need a completely depression-free North Atlantic for that for at least 4 consecutive days which is never going to happen.
There is almost always some nasty depression out there somewhere where you don't want to be and aren't going to be. This kicks up a big wind sea and the rollers then emanate from the center of the depression or the area of strongest winds as the ripples do when you throw a stone in glassy water. Larger waves travel faster (I read that the tsunami wave hitting Asia traveled at jet airliner speed). An they go great distances without losing their strength. So a day or two later they reach the warm and sunny and mostly wind-free area where you are.
When we moved down the Portugese coast in Fall 2013 we had plenty of opportunity to see swell by itself as there was a series of depressions taking a southerly route and giving us strong headwinds. So we had to wait out the storms repeatedly and then motor south in the windless windows between them. In all, we motored or motorsailed 80% of the distance from Hamburg to Rabat, Morocco. And in the Atlantic we always had significant swell, coming from wherever.
There are rarely stormy winds in Portugal but only 3 harbors on it's Atlantic coast are safe to enter in any conditions. All others have a bar over which the swell breaks. In early 2013 a German 44ft sailboat was totalled in the entrance of Figuero da Foz causing 2 deaths and this was in near dead calm. For all I know, the swell that did this may have come from a depression near the Falkland Islands.
So, getting back to the topic and answering Ben's question, my radar did paint the real target very well when on the top of the wave but then it was lost again a moment later when in the trough. So it's inconsistent and in that it's just like all the other false echoes from seas.
If the real targets would paint at every sweep, they could be seen even if embedded in all the false echoes from seas.
If there were no false echoes from seas, even an inconsistent real target would be seen.
As it is, the real targets look just like all the false targets until as close as 4nm with my radar mounted low in the conditions that we had, which were, I repeat, not severe but as nice as can reasonably be expected in this area (mostly 18 to slightly more than 25 knots true from the aft quarter, making for apparent pretty much on the beam with wind sea no more than 3m, 9-10ft, but with unknown ocean swell underneath).
And yes, there are many blue water boats with BR/3G/4G. And I'm not thinking of replacing it, partly because we aren't planning any Atlantic sailing for a couple of years.

Posted by: Henning at December 17, 2014 4:17 AM | Reply

15 Replies

  • Henning,

    How high above the water line is your radar mounted?

    I will (hopefully) do an AZAB this summer so we can compare notes afterwards. My 4G is on the first spreader, 8.6m above sea level. So far my experience on the North Sea and inland is that this is a good mix between close-in performance and at-sea. We'll see how this works out on the ocean.

  • Kees: my 4G radar is 4metres/13ft above the water. And I had already thought of your boat as the ideal test platform to answer this question: a 4G radar mounted higher and going to the same sea area as I was in.
    So when you have arrived in the Azores or latest after getting back, we will know.
    And your radar is fixed not self-leveling, right?

  • Correct, it is fixed.

  • Unfortunately I can completely confirm the very poor performance of the 4G! I would even go this far to warn anybody wanting to use this setup for offshore cruising.

    1) I have nearly the same setup, 4m high gimbaled, the MFD is a Lowrance HDS touch 12.

    2)The problem is the radar itself and not the setup!

    3)That was my last Navico product!!!

    4) I will put a 2nd radar at spreader height even if this looks strange but I don't want to remove the post that carries the solar panel as well.

    5) It is working fine for inland!

    6) Even if you hardly find any complains on the internet
    you will find the many advanced user or pros tell about their issues with 4G once you speak to the in person (my experience)

    I have used radome radars on sailboats for more than 20 year now, so I am trained to manual settings and also to do offshore cruising with it. My main experience comes from a 46ft steel sailing vessel using a mast fixed radome at 7m. It was a Furuno firstly, that later changed to a Raytheon Pathfinder. Both 4kW 24in.

    Both worked fine on Atlantic crossings and coastal cruising!

    The boat was "upgraded" with a 2nd Raymarine radar (2kW)
    on a pole due to display (AIS) incompatibility and the fact that the mast mounted scanner was still good with its CRT Display.

    It was observed, that the 4,5m high gimbaled radar did perform as well in high North Sea swells as the mast mounted, mostly even superior when heeling, still having limit in very high sea states.

    And yes that is where a cruiser wants to use the radar!

    Sailing in the dark avoiding to hit unlit obstacles at short and medium distances.

    It saved me at least twice from major repairs :-)

    With that background I thought it would be absolutely a
    good idea to fixed a 4G pole mounted on my current boat (40ft) how wrong I was...

    My current scanner is roughly a year old, it had to be changed as the one I originally bought turned out to be a watermaker instead of a radar, collecting water inside the radome due to a design error!
    A complete no no !!!
    By the way that appears to have effected a whole series, I never read about this unless I made some advance research on the net. And that's the main reason why I don't trust a company that fails to run a recall campaign for such a severe issue.

    Back to the 4G, I found it really nice when I did test runs on a canal during a refit it was also looking promising on Dutch inshore waters incl. Ijsselmeer. I had some issues with firmware 4 to 5 on the HDS but firmware 6 solved it.
    My first crossing of the English Channel was an eye opener. It was really hard to get really big
    buoys on the radar further than 1nm in moderated (4bft) conditions. Closer it worked better but not
    as reliable paint were achievable as I would be used to have on a small 2kW scanner at same height.

    From that point I adjusted the Radar manually all the time, a really pest on a MFD.
    Later it turned out that the "beam sharpening" setting (medium) was the issue.
    Turned off, and gain pretty high you would see more but also get more interference from sea state.
    Resulting in quite frequent adjusting of the settings :-(
    Later I found that the "beam sharpening" set to high would offer new passages trough the Cherbourg (France) breakwater ;-) have a look on a chart how big it is...
    I am currently based in this region so radar is vital what can i do?
    I made my decision that the 4G is not a suitable radar in this region in my setup, it could improve mast mounted but I doubt that would change the situation significantly.
    So I keep the 4G as a backup as it is running with openCPN as good as with the MFD.
    Beside that I will put a radar at about 6m fixed mast mounted.
    I tend to use Furuno for the known high quality of their radars. Unfortunately that seems to change too if I look at the Wlan radar (nearly 7°!!! horiz. ) leaving the commercial 24in scanner as an option.

    As I already have some Raymarine equipment so the Quantum could be my choice as well because of the dimension and the low weight (5,2kg). It could also connect to the Stng network straight away.

    Anybody having offshore experience with the Quantum???


    Summary:
    4G buy it straight away if you own either a motorboat or use a sailing vessel for nice weather cruising. If you are seriously cruising in offshore conditions or areas where a radar is a must, don't even think about that one. Buy a standard magnetron radar or wait until there is real life evidence of the performance of pulse compression radars.
    Never ever trust the promises from the manufacturer or test in sailing magazines (done in harbour setups) I was stupid enough to do so...

    I received a fantastic support from Navico Germany with all previous issues (rain problem and yes, my MFD had to be changed 2 times as well) but at the moment I have no feedback concerning the 4G issues other than that would be new to them. Fair enough they offered to have the system checked which is not an option as I am over the warranty period.

    @ Henning did you report you issues?

    I am happy to change experience and data with anybody to improve the situation even to learn that I am wrong...

    please use radar(at)sailing-salmon#com for contact


    @ Kees what was your experience?


  • Sorry for your troubles, Salmon, but there are many experienced boaters who are quite pleased by the 4G. I may be a power boater these days, and I do avoid big seas as much as possible, but here are some comments:

    * As to durability, the 4G I'm long testing was installed on Gizmo in late 2011...

    https://www.panbo.com/archives/2011/12/simrad_broadband_radar_4g_hands-on_1.html

    ...and was still working fine in late 2016:

    https://www.panbo.com/archives/2016/12/testing_the_garmin_fantom_24_in_a_new_world_of_solid-state_radar.html

    That means it's done two round trips from Maine to the Carolinas, sometimes somewhat offshore, and is experiencing its third winter without cover. In fact, it's got a few inches of snow on it right now, and has been through numerous rain, freeze, thaw, snow etc. cycles recently, but I'll be surprised if it doesn't fire right up, hopefully soon (once done my belated hydronic boiler install).

    * As to beam sharpening, it's an optional feature, and, yes, the high setting will definitely put unreal jagginess in many targets. But it can also separate real targets in some situations. I don't understand criticizing what you see at the extreme setting when it's really easy to change?

    But maybe I don't understand what you see for a 4G interface, and I do fear that you're missing some 4G's performance using it with a Lowrance HDS Touch 12. Do you have 3 levels of beam sharpening, plus off? Do you have independent dual range? I commonly use 4G on NSS evo2 with the longer range set to no beam sharpening and the near range to medium. Also, I almost never change the gain from auto and I'm a fiddler (with no messy rigging to fool with ;-)

  • Hi Ben, Thank you for your reply.

    1) No doubt that a proper 4G will last long. The one I had suffered from construction faults. And I blame the manufacture for not recalling it once they were aware of the issue. However I hope my new one will work for some years...

    2) At least in Europe beam sharpening was advertised as improving the radar performance significantly, giving the 4G a near small open array resolution.

    So I would not consider it as an option! There must be an option to turn it off in some cases, right. But when I am approaching a harbour I want to separate targets to follow a channel and identify traffic within that.

    In my case that setting on would lead to a very poor target return and you could easily miss targets! Turning off beam sharpening on the other hand would lead to a poor resolution like on a Furuno 1623 unit. Why should I have a radar that can`t use the main feature?

    Unfortunately I don't have dual range, certainly that would improve the issues somewhat.
    But I can adjust the beam sharpening to 3 setting with the latest firmware.

    The short range capabilities are outstanding but it is sad to find out that a 2kW Pathfinder would have done better in a range from 0,5 to 4 nm.

    Your reaction comes close to the one from Navico, I think my report is easily considered to be to negative and it likely to think the problem sits in front of the device..

    However, once my boat is back in the water I will provide some images to show the issues.

    I have in mind that my rigging is affecting the 4G more than it would on a pulse radar so that could make the difference compared to your experience.

    Finally I would be very pleased to get a statement (via e-mail) about your experience comparing the Quantum and the 4G.

    Thanks a lot!


  • Hi Salmon,

    I have sailed about 15000 miles at sea with the 4G installed, about 25% with the radar on (that's what you get when developing the OpenCPN plugin and without a microwave that has a limited lifespan there is no reason not to have it on ...) and I am still very satisfied with the Navico 4G radar. I'm recalling one trip in particular, up to one of the Waddenzee gaps (Westgat, west of Schiermonnikoog) in 30+ knots / 7 Bft / seastate rough where I was easily able to discern the location of the bouys, very important there as they move almost bi-weekly sometimes. Also in the wider ocean with high swell no issues for me.

    So I can definitely say that with my installation there is nothing wrong. My radar is installed on the starboard first spreader, about 9 m above sealevel.

    If you had a radar with hardware defects resulting in water damage can't you elaborate a bit on that? Can you show us some pictures? Can you show us the difference with your new model?

  • Hi Kees (and all of you),
    We´re gearing up our boat for "retirement sailing" (around the World) and I´m right now looking at the Halo with the 4 or 6 ft antenna for our boat (kind of the same type of radar as the 4G, as far as I understand?).
    My plan (so far) is to put it on the top of the mizzenmast (to get the rotating antenna free). That would be at about 13 m / 43 ft above sea level. Maybe I´ll make a manually hydraulic "leveling" mount to improve the sweep angle when the boat is leaning at steady wind (depend how much time I got left in the process).
    I´ve been curious of how much reflexes and/or disturbances you may get from the rest of your rigging and mast with these pulse compression type of radar? (as the main mast will be about 6 m / 20 ft in front of it)
    I´ve looked around for information in the subject but there is not much said nor written about it (until here and now) - where I looked anyway...
    Any experience or comment would be most appreciated.
    Thanks, Swede

  • Hello Swede & Cia,

    You haven't said but googling for Ketch Siri, I think your boat is a Roberts 44 CC Offshore, 44ft?

    Halo is not a FMCW (BroadBand) radar, it is a fully electronic (no microwave) pulse compression radar, like the new Furuno/Ray/Garmin radars. It is significantly heavier and uses (much) more power than 4G.

    I don't think this is an appropriate size for a 44ft sailboat, certainly not at 13m high. We're talking 23 to 25 kg. Think of how many kilos of keel ballast you're negating. Rough guess, 23 x 13 / 1.5 = 200 kg... And it uses at *least* twice as much power as a 4G, because you need to swing that arm through the wind.

    I'd say the best location and type on your boat would be a radome before the main mast, at about 6m high.

    If you really don't like FMCW radar, go for a different brand radome (e.g. Furuno/Ray/Garmin.) However, these are all still new as well, so which one is best I can't tell you. I happen to think FMCW is actually better, as I like the close in performance and lower power draw and instant on capability more than the
    lower performance > 8 nm. I don't care about radar targets that far off (other than big squalls, which works fine) as GPS tells me where I am and AIS tells me where the big boats are (and warns others of my location.)

  • Hi Kees,
    Yes, you´re right out about us. Cheers to a quick finding - like to have guys like you at the rescue center...
    Pleasure talking to you.
    I wrote an answer, and it got long...
    ...as I realize the Halo is´t the same function as the 4G, I decided to just post here that I thank you for your fast reply and good inputs.
    Also want to thank Henning and Salmon for their honest review (of their opinion, how it works on a blue water sailing vessel) and detailed description of installation and so on.
    - You can´t find these at the manufacturer´s testimonial display... Big THANKS ! :-)
    It got me to think and I will post my long answer at a new thread "Halo radar, pros and cons" as I don´t want to hijack this discussion more than I already did (excuse me).
    Of course you´re welcome to join if the subject interest you.
    / Fair winds, Swede

  • Hi Kees,
    The OpenCPN plugin is really nice, I really appreciate all the work that has been done to develop it.
    I use it most of the time on a 21" screen, the MFD is just switched on when the sounder is needed as well. Is there a way to use dual range side by side on the screen with the current plugin? Currently I am just able to switch between A/B settings via the tab.
    At the moment my boat is on the hard and I just went there to have a look what impact the beam sharpening settings have with all other settings set to standard. BS switched off would result in really bad radar images.
    If you provide me an e-mail address I will send you these images as well as the photographs I took of the water catching radome. One of the sources from which I learned about the issue is this one:
    http://www.thehulltruth.com/marine-electronics-forum/659129-lowrance-3g-radar-water-intrusion.html
    I mentioned in my first post that I don't think my setup would be the problem but the radar itself, reading you experience (I know your area quite well) gives me the idea that the FMCW could work in front of the mast (do you have it there or on the spreader) but is affected severely by all rigging parts ahead in my setup. That never was an issue with the 2kW puls radar on that boat with nearly the same heavy duty cruising rig. I would really like to avoid having the radar at the mast due to several reasons from cable runs to having mast steps in the way, weight aloft e.g.
    Putting a second one up there would also be the last option I still hope to solve the problem.
    Yesterday I just was able to have a look at the Quantum attached to an Raymarine Es 9" display (on the hard as well) and wasn't very impressed. Actually it was on a motorboat not very high above the ground so I will have a look again when it is back in the water.
    Groetjes!

  • Hi Salmon,

    1) Plugin. Sounds as if you are still using v1.3. In v2.0 you can have separate PPI windows for both radar ranges on screen simultaneously. Only one range can be overlayed over the chart though. It is way better than v1.3 also in display quality and performance.

    2) Ahh, a breather valve that can be closed off if the installation is incorrect. I guess that makes sense, as does the improvement where they moved the location of the valve so it becomes less likely it is blocked. I will check, but I think I have the old breather location but the radar is mounted on a small aluminium pedestal but with washers between the pedestal and radar.

    3) My radar is on the spreader. I get bad performance for the sector where the mast is in the way, but that makes sense. Note that Halo allows the user to define a masked sector where no transmission is done at all.

    4) If you are looking for a different brand with high performance I'd go for Furuno, probably the NXT version.

  • Because of the focus of FCMW radar on short range, I always considered a low mounting position as natural for a 3G/4G. On the average (sloop-rigged) sailboat, that is a pole at the stern.
    I also once had a magnetron radar mounted above the first spreader and in the Kiel Canal it would not even show me the banks of the canal, just farm buildings in the fields on either side of it.
    But when looking at Kees' experience, maybe that was a wrong assumption.

    Also, I believe my Scanstrut self-leveling mount contributes to my offshore problems as it is overpowered even with a moderate weight radome like my 4G in ocean seas. The result is overswinging, which, I believe, will cause erratic returns which may then get filtered by the seastate filter.

    So for those that are planning for a 3G/4G installation, they should probably consider a fixed mount (or manual leveling) and higher position (like 6 to 8 meters).

    But in any case, traditional magnetron 4kW radars are not reported to have problems with mounting positions on poles at the stern, or with self leveling mounts.

    And my 4G has serious problems holding onto MARPA targets even in near flat water at a range of 2nm and less, the tracked target vectors are still messed up and the "MARPA fix", developed for the HALO, is, as of today, still not available for the 4G.

    I have to say that I have become tired of this. Rather than growing out of a so-called "recreational radar" I would prefer to grow into professional stuff, which for me means a Furuno 4kW magnetron stand alone radar. When the time has come around, I'll report my findings here.

  • Hi Kees,

    Thanks for the hint just tried the latest plugin today, hadn't looked for any updates since July. The performance seems to be very good but I am afraid it's less user friendly as the previous version: e.g. I clicked on hide radar... and found no way but via reinstalling it to get the screen back on the display. It's also a lot of open windows to work with. Sorry for this moaning at a high level ;-)

    In my case the breather wasn't even covered but looked like sealed by error within the manufacturing process. I think it was nearly 1 litre in it...

    Henning, it looks as if you had the same ideas prior to install and purchase as I had. Seems like we believed too much in the adverts.

    In this case I could not disagree more with Ben (sorry ;-), describing it as "optional feature"
    All efforts were made to state the beam sharpening as THE key feature.

    http://www.lowrance.com/en-US/Products/Radar/broadband4g-radar-en-us.aspx

    look at the specs. : 2,6° beamwidth (Effective), sorry that is deception.

    I guess the very good reputation (making us look like naggers) mainly does come from "puddle conditions"

    https://www.youtube.com/watch?v=MwCvkdkNZ28
    https://www.youtube.com/watch?v=eUXLf0iving

    I tried to find some reports about offshore or coastal use in moderate conditions, nope!

    But I noticed some units installed on commercial boats as 2nd radar. That makes sense! Certainly they wouldn't complain about poor offshore performance when they use the advanced unit then anyway.

    OK lessons learned, I am looking forward to hearing about your ideas to solve the problem.
    I fear that the Furuno NXT has the same weaknesses and think about mounting a Garmin HDx pulse radar to the mast and run it via the PC (cost friendly) or get a independent pulse radar set e.g. Furuno 1715 or better 1835.

    Still I won't like the idea of a radar aloft for several reasons.

    Fair winds!

  • As I've mentioned from time to time in test reports, I think that all the solid-state radomes are more sensitive than magnetron radars to onboard obstructions. And maybe the FMCW type is more sensitive, though 4G is better that way than the original Broadband.