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Old 18-03-2016, 03:20   #106
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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Fair enough, I agree.

Nor was the signal ground actually a ground in the equipment I worked on decades ago. Where a digitally controlled radar countermeasure transmitter's "computer" was housed in several seperate black boxes, because of space and lack of miniaturization. Rather it was a simply a completed path for data flow.

A signal pair, or in some cases 64 pairs, sometimes running the full length of the aircraft.
And I agree. I don't know why they call it a "signal ground" -- the phrase seems nonsensical to me. But NMEA0183 v1.0 et seq but before 2.0 had common negatives which could be wired together.

Maybe that's Rustic's problem?
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Old 18-03-2016, 04:41   #107
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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The question was whether antifouling through prop (not the anode) would have much effect, and whether people do it.
I antifouled my prop and answered the question.
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Old 18-03-2016, 06:54   #108
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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And I agree. I don't know why they call it a "signal ground" -- the phrase seems nonsensical to me. But NMEA0183 v1.0 et seq but before 2.0 had common negatives which could be wired together.



Maybe that's Rustic's problem?

It is about symmetric vs asymmetric. 232 is a signal measured against ground, meaning it varies between zero and higher; it is asymmetric. 422 is symmetric and the signal goes negative as well as positive. One conductor carries the positive part (when viewed against ground) and the ither the negative part. It has no signal ground but ground is used to shield it.
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Old 18-03-2016, 07:15   #109
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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It is about symmetric vs asymmetric. 232 is a signal measured against ground, meaning it varies between zero and higher; it is asymmetric. 422 is symmetric and the signal goes negative as well as positive. One conductor carries the positive part (when viewed against ground) and the ither the negative part. It has no signal ground but ground is used to shield it.
Thanks!

Very clear and useful explanation.

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Old 18-03-2016, 07:45   #110
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Re: Effect of Prop Antifouling on Prop Anode Wear?

Ah, makes sense. No network on my humble craft, or ais, wind, radar, etc.

But do have redundant depth, vhf, charting, and paper charts and tools. Will never be more than a coastal sailor, but enjoy reading about those that wander far and wide.
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Old 19-03-2016, 00:42   #111
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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And I agree. I don't know why they call it a "signal ground" -- the phrase seems nonsensical to me. But NMEA0183 v1.0 et seq but before 2.0 had common negatives which could be wired together.

Maybe that's Rustic's problem?
Yes, I have worked it out, no thanks to Raymarine tech guys. In the manual it's called a Ground (drain) wire. Now, whilst it doesn't say to connect it and the black negative cable together, that's what I've done and it's working fine. It does say,

"the power cable supplied with this product includes a dedicated shield (drain) wire for connection to a vessels RF Ground point", that's the thin black wire I was talking about. It goes on to say,

"It is important that an effective RF ground is connected to the system. A single ground point should be used for all equipment. The unit can be grounded by connecting the shield (drain) wire of the power cable to the vessel's RF ground Point. On Vessels without an RF Ground system the shield (drain) wire should be connected directly to the negativie battery terminal" which is what I have done.

I'm really not familiar with the RF ground system at all.
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Old 19-03-2016, 21:34   #112
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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Hmm, well, that all sounds logical enough. I wonder what knowledgeable others have to say about it?

I have a lot of faith in the designers of my electrical system, which is the best I've ever seen on any boat, but -- you never know.
Some further discussion on bonding :
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Old 19-03-2016, 21:35   #113
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Re: Effect of Prop Antifouling on Prop Anode Wear?

The rf shield is the braided wire around the center conductor of a coax cable. There to prevent rf energy from being induced into the center conductor and causing interference.

If not grounded it provides little protection. You done good.
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Old 20-03-2016, 20:18   #114
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Re: Effect of Prop Antifouling on Prop Anode Wear?

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The rf shield is the braided wire around the center conductor of a coax cable. There to prevent rf energy from being induced into the center conductor and causing interference.

If not grounded it provides little protection. You done good.
I'm glad I did well, because I had no idea what I was doing

|My rf cable is exceptionally small thin wire, which was grouped in with half a doz other 'data' cables.
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