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Severed cable

Old 04-04-2003, 03:47 PM
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Default Severed cable

Did a stupid and severed the transducer cable - can it be spliced or is it shot ???

Thanks in advance !
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Old 04-04-2003, 03:58 PM
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A well done,soldered repair with waterproofing is a fine repair.Foil shield make it little harder to achive,but should not present a problem.Good Luck
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Old 04-04-2003, 08:49 PM
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the foil shield is simple. Just wrap some aluminum foil around the repaired splice heat shrink the boa's bulge down and and you're good to go.
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Old 04-04-2003, 11:40 PM
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tugs REPLACE it if the splice will be or can be in the water or you could fix it "right", if the splice is where it will not be subjected to water.

Sea_Dad's aluminum foil wrap is not fixing it right! But in a pinch it will do. Wrapping it with foil is not 100% and it needs to be 100%! Solder a small wire from one side of the braided wire splice to the other side of the braided wire splice; this is 100%; then seal the repair (I will explain why below). What if you get corrosion between the foil and the braided wire or you don't have a bonded contact between the two? You then have nothing, zero, zip, f---all. But you do have serious RF losses. This RF loss can interfere with your other equipment and other peoples equipment, and you will be in violation of federal laws.

The braided wire that sheaths the inner wires is there to prevent RF (radio frequency) loss. It also serves to protect RF from entering the signal carrying wires. There is MAJOR FEDERAL LAWS governing RF losses Sea_Dad. You say you've got 20-30 years as a electrical engineer, you should know this stuff then. Repairing your own is fine by me, but don't advise others to do something half assed that can land them in court! These guys don't fool around when they come knocking. The first thing they do is seize the devise that is in infraction, and then serve you papers for court; if they're knocking, your guilty, period! (If you want to put a penny under a household fuse that is your right, but don't advise others to do the same). You might not have liked my wire ideas, that is your opinion; but no harm can come from my methods, but your foil idea can land others in court and with loss of equipment!

tugs, the braided wire is grounded at the end closes to the devise; which grounds the whole length of the braided wire portion of the wire. By grounding the braided wire it like makes the braided wire into a negitive force field so to speak. Basically all wires that carries a current/signal emits an electrical magnetic energy. Think in terms of the magnet under a thin sheet of glass with metal filings on top. Well that's what wire does along it's length. The grounded braid contains that energy. It gives that energy a place to go to, and grounds it out, shielding the environment from leaking RF.

Therefore braided wire serves to protect other devices and wires from picking up this released energy signal (RF). The braided wire also serves to denies stray RF signals from entering into the signal carring wires. This is why it is very important to do a 100% repair job the first time or replace the wire.

Once bitten, twice shy
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Old 04-05-2003, 04:14 AM
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LOL Garett you are so full of crap dude. quote: It gives that energy a place to go to, and grounds it out, shielding the environment from leaking RF. From the sounds of it, you need a metal braid around you. LOL

The guy is asking about a transducer, not a 50 KiloWatt Radar unit in an F18 fighter jet. The aluminum foil will in fact complete the circuit, and it will help him from picking up noise from the engines spark plugs. Thats the real concern with them, not radiation.

You need to know the subject better, if you want to teach me something. You're talking about 200Khz, not 2Ghz. (do you even know what that says?)

By the way, my Raytheon L750 came with a foil wrap on the cable for the transducer. It does not have a metal braid.
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Old 04-05-2003, 04:31 AM
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Do the right way. Go out and buy a coax repair kit, it will have the splices, outer braid sheathing and heat shrink. Makes for a permanant fix. If you can't find one drop me a line and I'll dig one up for ya.
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Old 04-05-2003, 07:26 AM
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Yea and it's a violation to remove the tag from a bed.

My limited experience never have I seen a power/data cable that couldn't be spliced successfully, with very limited signal change. There are timing, signal strength, and RF issues. Regardless if it's high speed parallel or serial data connections including fiber optic, coax, and twisted pair. The most difficult thing is making sure you do not cross connect wires, use heat shrink sealing the individual conductors and cable from water intrusion.

The foil shield isn't that big of a deal, alum foil wrap over, seal with a layer of heat shrink would be perfect but probably isn't necessary IF there is a non-insulated wire inside the bundle that will maintain electrical connectivity between the foil shield. Yes the 3-4" section of the splice will leak and is subject to rf. And if there isn't a non-insulated wire then you could strip and lay one inside to contact both foils.

I've cut 15ft off my radar scanner cable and repinned the end (after consulting with Raymarine BTW they said I should not go shorter than 10' total length / timing issues) then I cut about 20ft off my 33' WAAS reciever (had to move the reciever I 5200ed to the helm up to the roof, twisted the reciever case and stripped/popped out one of three retaining screws, took it apart and used a bigger screw, works fine).

So, strip 1/2" off mating conductors slide on a little heat shrink (2 pieces if you like) push the conductor strands inside each other, twist, solder, shrink the wrap. If you stagered the joints then you can sometimes cover the bundle with origional outer insulation cover. It's a reel pain when you get all the conductors soldered and looking good only to find you forgot to do step one after the cable cut. Slide one or two pieces of shrink wrap over the entire cable first

I'm not an Engineer just an ET that's old enough to remember IBM mainframe computers big a refrigerators that used Core Memory (charge wires running thru little iron rings with a wopping storage capacity of a few K,)

[This message was edited by HookMan on 04-05-03 at 10:41 AM.]
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Old 04-05-2003, 08:27 AM
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You kinda lost me , and now I'm scared!

I follow the part about a good splice, shrink wrap and all, but that bit about bed tag removal violations... DO I NEED TO CONSULT WITH AN ATTORNEY?!

The Truth is that Saddam has SARS- Acute Severe Regime Shrinkage!
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Old 04-05-2003, 08:42 AM
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On the same subject. Anyone know where I can find a 6 pin connector for a JRC 500F?

I had to splice my GPS antenna cable. I have it slpiced for now to fine tune and place everything. But I would like to redo the plug. And since I have no way of getting the plug home I will need to do the work on the boat. I am not patient enough to un solder the old plug and re solder the new wires.
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Old 04-07-2003, 08:59 PM
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It's not very nice to embarrass any of the guys on the board. I'm sure you could have said it better than how you did.

We are all here to get information and to help others to do the same. We not all agree on some of the ways we go about repairing our equipment but I think we can do it without embarrassing someone to get our own point accross.

We do appreciate your posts though.

Happy posting............Booby

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Old 04-08-2003, 07:55 AM
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First, I think that both Garett and Sea_Dad are correct, but either approach by itself is lacking in my opinion. Combine the two and you're good to go.

So here's my reasoning: the tin foil is a good enough shield in itself. Many types of coax use it as a shield, sometimes by itself but sometimes also with a copper or aluminum braid (the braid can actually be a pretty poor shield in itself, depending on quality). The purpose of the shield is to prevent "leakage" from the center conductor to the outside world, and also to prevent noise "intrusion" from outside devices, cables, etc.

The other purpose of the shield is to provide a uniform potential for antenna and ground currents. If the shield (either foil or braid)is broken, the potential changes and then there is the possibility for leakage and ground loops. You need to restore this uniform potential.

Wrapping tin foil around the splice is a good shield, but doesn't restore the uniform potential of the shield (unless you can ensure a good mechanical connection between the tin foil and the braid). I just don't think shrink wrap provides the mechanical pressure to hold up over time.

Soldering a short piece of wire across the open part of the braid should restore the uniform potential if done right, but a wire is nothing of a shield.

So, I would do both the soldered jumper (better yet use some braid or mesh), wrap it in tin foil, cover it with 5200, then shrink wrap it.

Actually, if it were really me I would use a coax splice connector kit (check with Shakespeare) that doesn't need any soldering or 5200.
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Old 04-08-2003, 09:57 AM
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Nice Preoccupation.

The reason I offered the foil as a fix in case the other approaches failed is because of the intended repair.

The discussion was for a tranducer, not a vhf or a radar. It's main concern is noise interference from the engine. The foil will work fine for this use.
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Old 04-08-2003, 11:48 AM
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If you cut it near the transducer, and the repair will be in the water...replace the transducer. They are not that expensive. I am assuming it is transom mounted, not thru hull.

I rely on my fishfinder too much to let possible extra signals(noise) on my screen. If you do what Preoccupation says, it SHOULD be fine, but if you get a new one, it will be fine.

Casey
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Old 04-11-2003, 11:23 AM
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Preoccupation,

I try to be clear on my descriptions in a way that all can understand, but apparently I do not always succeed. I did fail to identify rolling back the braid onto itself. Then do the splice work, then rolling the braid back over the splice. By doing this, the braid will over lap itself, then soldering a wire from one side to the other side, seal and your off to the races.

Boody Trap,

Well put. Not only do our engines need tune ups every once in awhile but it is good for us as well. Thank you, I'll try be more mindful. I do what I do very well, but someone out there likes to ride my back. And that has got'ten under my skin; I should not have let that happen. Cheap shots benifits nobody.

General comment,

If you collect enough pennies you could buy a house. Point being, if we don't deal with the small amounts of RF losses on an individual basis then we will all suffer in the long run. It sure would be a crappy deal if you were trying to send a destress signal but couldn't get through because of to much RF interference in the area. And that is why there is Federal Laws in place governing RF. Gesshhh, sorry for being long winded.

Once bitten, twice shy
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Old 04-11-2003, 11:47 AM
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No problem, I don't always describe things the best way either, or I sometimes leave out some little detail that someone catches....but that's why we're here, to learn and help each other out.
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Old 04-11-2003, 03:01 PM
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Just so you are fully informed Garett, 200Khz is not considered a radio frequency by the FCC. No one is going to be running around with a rf sniffer looking for his fishfinder to be leaking anything. Although his cat may hope it leaks some fish stuff out.

If I tell you something or correct a post of yours and it doesn't sit well with you, just shrug it off, dont let it bug you.

But if you wanna correct me, you're gonna need more schoolin son.
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Old 04-12-2003, 05:26 AM
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I prize civil discourse too, but Sea Dad is right to have gotten a little harsh on this issue. Garrett has some very weird -- let us charitably call them "unique" -- notions about electrical and RF energy that have also been displayed in prior posts.

It's one thing to express an opinion as a fact, as in the usual thing we see here ("my Scout 202 rides better in a 5 foot headsea than a Viking 70"). It becomes a problem when someone posts looking for technical advice and they get gross misinformation.
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Old 04-12-2003, 12:16 PM
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quote: let us charitably call them "unique" -- notions about electrical and RF energy

I think this can explain why Garett feels so strongly about RF leakage.



One more then I'll quit

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