Re-connecting Cut Radar Cable - Help Please

[Wotname]

Originally Posted by Guy

Hey Wotname: Give me a TB# from the radar airframe wiring diagrams. I would like to check into this. Maybe the Britts are still using 1942 technology and thats why they don't sell many fixed wing A/C anymore.

Yea, maybe that's why .

OK, I can't remember if they used TBs in the radar wiring - but probably not.

However you claimed that TBs would not be used in critical equipment; I don't think weather radar is critical - maybe that's just me .

However much of the Com wiring was via TBs and in my world, comms are critical - no comm, no fly.

Was called out one Sunday night for no pilot's PTT; should be straightforward I thought, the bludi expensive BAe PTT switch failed regularly - change the switch and go home early was the expectation. But no, not that night - the PTT wire was broken at the crimp PIDG terminal behind the pilot's instrument panel. The only access was to strip out the instruments, remove the panel, replace the broken crimp, rebuild the panel and then go home about 6 hours later

There are dozens and dozens of terminals on the TBs behind the instrument panels but this was the only crimp that ever failed IIRC. I assumed it was badly crimped during manufacture and finally failed after maybe 15,000 hours of service . There was no external mechanical damage to the terminal or wiring and the loom was very well protected and supported

[model 10]

Thats why you get the big bucks.

[phorvati]

I had to cut the cable at the 18 pin connector to the main display unit of JRC 1000. It had intermittent connectivity issues. I found it to be both the plug, and the PCB thru hole connector. Touching up the PCB connector was relatively easy, but re-assembling 18 pin into a plug in a manner so to stay short and un-exposed to external elements... that was a was a bitch. It took me 3-4 tires, while re-cutting the cable and starting over. It takes patience, soldering skills, steady hand, good tools, excellent eye sight. Most DIY don't have that. Hence, the terminal strip. I have the terminal strip at the mast base as well, works good. If i get some time, i might order those plugs, and do it that way.

[montenido]

Splicing update:

After all that work, it appears that my radar is now not reading contacts (other boats, etc.). Damn! I'm not too sure how to trouble shoot the terminal strip and ring connectors, so I might just re-cut and solder each conductor together. Everything was working just prior to cutting, and appeared to be working after reassembly.
I have a Furuno Navnet unit. Any other trouble shooting suggestions before going back into the cable?

Thanks, Bill

[montenido]

Hi all,

Well, after spending most of today cutting the splice out and re-splicing the radar cable with soldered joints (same problem) and then crimps (same problem), I am throwing in the towel and ordering a new cable. All the ring terminals that I cut off had good connections/continuity when I checked them later. I should mention that I cut the cable in the middle, as opposed to at one end or the other. This may be what is causing me problems.

My problem is that I want/need radar for an overnight passage this Thursday, so time is short for trouble shooting. New cable was $235 plus a big hit for rush shipping.

Oh well, I wont be cutting any large data cables again.

Thanks for all the replies.

Cheers, Bill

[Paul Elliott]

Bill,

I am concerned that the problem is not in the cable splices, but at one end or the other, or with the scanner or display. I know what they say about theory and practice (*), but if your splices were connected properly the radar should have worked.

* In theory there is no difference between theory and practice. In practice, there is.

[noelex 77]

Bill
It is strange that its not working properly. A splice in the middle of the cable should be fine. It sounds from your description (and your post 39 that it was working)

Originally Posted by montenido

Splicing update:

After all that work, it appears that my radar is now not reading contacts (other boats, etc.).

That the radar is partialy working. Is this correct?
I am just wondering if its another problem, even something simple like gain adjustment that's flipped from automatic to manual.

Can you elaborate on the problem any more?

[donradcliffe]

If its firing up but not seeing images, the most likely problem is in the coax part of the cable. I assume you connected both the center conductor and the shield separately. Cutting it in the middle shouldn't matter.

[lancelot9898]

Sorry about being late to the party. Several years ago I installed a Furuno radar along with the chartplotter. While I did not have to cut the radar cable, I did have to cut the GPS antenna cable. Lots of little wires that needed splicing. I contacted the engineering dept at Furuno and they were very helpful even though they did state that they could not warrent the work. The whole splice was finally put into a hockey puck type water proof box. If I remember right there was something about the sequence of actually cutting the cable?? If you talk to the right engineer, they could lead you through the proper splice and materials to buy. It has given good results for the past 4 years.

[montenido]

Thanks for the further replies folks. Paul, I hope it is not a problem with the display or antenna, as they worked fine before I cut the cable. I have gone through all the settings to make sure that that was not the problem. I will be seriously bummed if the same thing shows with the new cable.

Cheers, Bill

[belizesailor]

Cut and reconnected my Raymarine radar a few years ago w zero problems using a terminal block.

Verify all your connections and if still a problem find a good tech and/or connect radome to a known good system and see if you get a display.

[Dockhead]

I had to cut a Simrad data cable (Ethernet-ish) in order to fish the cable from my helm. There was no other way to do it.

I despaired at first because some of the the internal wires are not marked at all. I had planned to crimp on RJ45 plugs and use a connector, but the guts of the cable look nothing like a normal Cat 5 cable.

But then I bought a telecom terminal block and just put the wires together with the screw terminals inside. I just checked each wire one by one with a continuity tester until I was sure they were properly matched.

It was simple and quick and works perfectly. You might start just by checking your splice with a continuity tester. Your multimeter probably has this function.

You might also think about shielding of the joint, presuming the radar cable was shielded.

There is no reason in the world why you should not be able to get your splice to work, so don't despair.

[montenido]

Hi all,

Okay, here is the very latest in this saga. I ordered a new radar cable and had it rush-shipped due to the fact that I was leaving to do two overnight passages. Well, it arrived and the radar was still not reading targets. So I did the passages without radar, which was fine, but not ideal. I again went through all of the menus and settings to see if there was something set incorrectly. I couldn't find anything, so I removed the radar and display, and took them to be bench tested at the local Furuno shop (where I bought the cable). They were unable to find anything wrong, but they did play with the settings and told me that it was now picking up targets.
So I brought it back to my boat and tested it in the marina. Hooray! It is now reading targets! Then I disconnected my new cable and tried it with my spliced cable. Once again, it NOW WAS READING TARGETS!!!!
So, the new cable will probably go on ebay, unless you guys think a spare is worthwhile, and I don't have to pull the new cable through my arch tubes, which is a huge relief, as that is what started this ordeal to begin with.
So all is well on Odyssey in the radar department. Thanks again for all the tips and advice.

Cheers, Bill

[Cheechako]

all my boats but one had the cable cut and respliced on a terminal strip with no issues. They were all the CRT type radars though.