First Post and a Radar Question

[capricorn]

Hi All,

My First Post ! I've been a Scuttlebut "lurker" for some months but having finally bought a boat after several years trying to convince myself I could afford/justify it (I can't but I've done it anyway) I reckon it's time to introduce myself.

We keep Capricorn, our Gibsea 282, in Chichester Marina. We're on the boat most weekends, the wine locker is well stocked and it would be our pleasure to welcome aboard some of those whose posts have brought me many a smile.

Anyway, I'm about to buy a JRC 1500 Radar for Capricorn and I have a couple of questions:

- I'm intending to mount the display in the cockpit. I understand that if interfaced to my GPS via NMEA it will also show position and waypoint info. My question is whether it will do this in standby mode as well as tx mode and if so, is the current drain modest enough to leave it continually switched on in standby to use as a GPS repeater ?

- Also, when installing the scanner cable, it would make sense to cut and join the cable at the point between it exiting the mast at deck level and going through the deck gland so as to allow simple disconnection whenever the mast is struck. Is the cable that goes to the scanner just a normal coax cable and is cutting and rejoining with a suitable connector advisable/striaghtforward ?

Best Regards

Matt



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[Talbot]

welcome to the forum. I have a new radar to fit as well. The advice I got was if at all possible not to cut the cable. The wires inside are fragile, and susceptible to noise, and you are likely to reduce the effectiveness of the radar. That being said, it is obviously possible to join, but I would recommend a quick mail to JRC in America (they have been very helpful) and ask what connector they recommend. Personally, I will be using a deck gland through which I will pass the cable, and will remove it directly from the display through the gland when reemoving the mast.

I ended up with a Furuno (long story)

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[Anthony]

Hi, Welcome!

No its not coax, it will likely be 10+ multicore sheilded cable. I would not recomend that you put any connection above the deck, its bound to fail.

If you have to break the cable then do it after is has passed thru the deck, and remeber to leave plenty of slack.

I have mine connected together on tag strip inside a metal box, which I ground, seems to have worked ok so far, and allows me to seal the cable as it passes thru the deck.

Please be careful I believe you may have high voltages up that cable, and not sure what it way do to your warrenty.

Good luck.

Anthony

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[AndrewB]

The question of whether a radar cable can be cut has come up before, with different views being expressed. Ours is cut, the cutpoint being in a shielded, waterproof box just beneath the deck, and has never given any trouble or problems with reception. As Anthony says, its 10-core, but there are no high voltages involved.

The GPS position does not display on my ST50 Radar in standby mode, but a JRC 1500 may be different.

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[peterb]

We have a Raytheon SL70. It's possible to split the display, so that one half shows the radar picture, while the other half shows GPS, etc., information, but the method of splitting the display is not immediately obvious. "If all else fails, read the instructions."

The standby mode reduces the current consumption, but it's even better if you turn off the scanner. That turns off the power to the magnetron heater, so that switching back on requires a 90s warm-up period, but it does give a very good GPS display without excessive current consumption while we are sailing.

Can't speak for the JRC, though. That's one of the problems with the RYA radar course; you learn on a radar simulator which will never match the facilities on your own radar. If you're getting a radar, then I suggest you find someone who has experience of that particular set and get them to give you some tips.

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[john_morris_uk]

Quick agree with some of the sentiments.

1. Don't know abou the JRC but on our Raymarine Radar you only get the waypoint info up when the scanner is on.

2. Our radar cable (which is a lot more than 10 way and includes three lots of coax) is broken below the deck. The join is via two multiway strips in a box above the headlining. I had the mast down, disconnected, mast back up, reconnected and took a deep breath --- and it all works fine.

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[tom52]

My cable is jointed below deck.I asked Raymarine first and they said no problem provided you tin the ends of the cables.
It also acts as an excellent GPS repeater with the scaner switced off or on standby

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[AlexL]

Hi

I have recently fitted a JRC 1000 which is aparently the same display but smaller radome than yours. Firstly in answer to your questions.
In standby mode I'm pretty sure the GPS Lat, Long, Dist and Bearing to next waypoint are shown in a little box in the bottom right of the screen all the time, transmitting and standby. Also when transmitting a little box with "WPT" in it is put on the screen over the waypoint location which gives a nice visual indication of where the next waypoint is.
I cut the cable just below the mast. My boat has a kind of hollow in the headlining moulding just under the mast specifically to give access to all the cables. All of my cables (VHF, lights, RADAR) are cut and joined just there. The cable goes through a deck gland and is joined just inside the cabin. The cable is not co-ax - it is a very thick (15 ish mm diameter) multi core. There are ( I think) 3 small 'normal' cores, 3 large 'normal' cores (probably power) and then 1 or 2 'co-ax' cores (probably a video signal) and then an overall braid. I just joined all these using chock blocks. Just make sure that each screen is connected to the correct screen and the overall braids are joined up. I haven't used a screened box or anything flash like that.

Some other thoughts - it is possible to disconnect the cabe from the radome so you can feed the cable without removing the big connector at the screen end - however if you are going to do this make sure you reconnect the cable before fitting the radome as it is not easy to do halfway up the mast! If you are going to cut the connector then this will not be necessary. My screen is mounted in the cockpit under the spray hood and is easily readable in all lights, even bright sunlight and is much better than going below to read it.
I have got 2 service batteries and 1 engine battery so current drain is usually not a concern, but I haven't noticed any extra problems with having the Radar on.
For the first few times after the radar was fitted I had it on all the time so I could correlate what I was seing on the screen with what I could see, this practice made it so much easier when we first used it in anger on a night crossing across the North Sea to ostend.

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[capricorn]

Thanks everyone, all very useful. Thinking about it properly, cutting and joining the cable above deck would indeed have been a really dumb idea. Capricorn also has a recess in the headlining below the mast where vhf, masthead light cables etc can be disconnected, I'll join the cable there.

I've mailed JRC US with some specific questions about what interfaced data the product will/won't display in Standby mode, I'll post their response when I get it in case its of interest to anyone else.

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[tcm]

Right then, that\'s radar sorted...

tell us about this large stock of wine!

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[capricorn]

JRC US Response

JRC's responce .......

Hi Matt,

Thank you for your interest in JRC products.

The Radar 1500MKII is exactly the same as the original Radar 1500 except for
the LCD panel. The MKII uses a Black & White LCD virus the original
monochrome LCD.

The advantage of the B&W is better contrast and slightly better viewing
angle.

The Radar 1500 (MKII) display will show the GPS data while in standby.

Please let me know if you have anymore questions.

Regards,

Buddy Morgan
JRC America


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[ParaHandy]

Re: JRC US Response

i split the cable and joined it right where it came through the deck, inside the boat, with a small potting box using a simple in-line connector to join the cables. There are two co-ax cables in the bundle so I soldered all ends and kept those two co-ax cables one "division" away from the others.

I then sealed the box with sealant. 2 yrs later, all still works ...

Connect GPS nmea to the NAV-AID and all should work. The info is displayed as expected although in quite small type which I find quite difficult to read. The EBL will then show the bearing relative to COG - not ship's heading, for which you will need HDG data fed into the other nmea input "COMPASS". I can give you chapter and verse on this if you ever do use the COMPASS nmea input ..... a bit of a b*gger ....

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