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Old 11-10-2017, 07:30   #31
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Re: Grounding Plate for SSB

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Kiss SSB. Got it as only "radio earth" counterpoise. Works great! Connected to ground lug on the auto tuner. Tuner tunes 40 feet wire from mast to aft end of the boat. Tunes all frequencues from 1.6 to 29MHz.
Icom ham radio and ICOM AH3 tuner....
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Old 11-10-2017, 09:09   #32
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Re: Grounding Plate for SSB

Bacchus-
One potential downside to the Dynaplate. There have been reports of them exploding. Literally.
What supposedly happens is that if you take a lightning strike, and it tries to exit via the Dynaplate, all the water trapped in the spaces in the sintered bronze superheats and flashes into steam. Explosively.
This may all be FUD so you might want to ask the maker about their opinion.

Many kinds and sizes of counterpoises and grounds will "work", but you might want to do some long and slow reading about the variations and options before really committing to any of them. The results, especially on boats, tend to be different because each boat, each installation, is a fairly unique place, from the radio's point of view.
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Old 11-10-2017, 10:29   #33
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Re: Grounding Plate for SSB

These stories of exploding dynaplate are not documented as far as i know.
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Old 11-10-2017, 11:31   #34
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Re: Grounding Plate for SSB

When you take a lightning strike, all bets are off.
I have seen and heard of holes being blown literally in the boat, often from a thru hull and sometimes just through the hull, for no seemingly apparent reason.
Iíd believe almost anything from a lightning strike
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Old 12-10-2017, 06:18   #35
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Re: Grounding Plate for SSB

Yes, lightning can put holes in a boat. But there is this "old wives tale" about exploding dyna-plates that surfaces every so often. I guess it could have originally been a simple thing like you suggest. But i also suspect it may have got started as an anti-dyna-plate marketing campaign. Like a lot of good myths it has some technically sounding logic in it but falls over at even a cursory analysis. I think it unlikely to be true. Would like to see pictures of an exploded dyna-plate due to lightning.
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Old 12-10-2017, 08:25   #36
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Re: Grounding Plate for SSB

I would rather have lightning arc through my keel paint.
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Old 12-10-2017, 09:36   #37
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Re: Grounding Plate for SSB

Yes, but you have very little control when the mast is hit directly.
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Old 12-10-2017, 09:50   #38
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Re: Grounding Plate for SSB

The Dynaplateís metal is too compacted to absorb water or it looked that way anyway, If it were that porus, it would bust very easily I would think.
Anyone have an unmounted Dynaplate? Put a hose against it and see if water passes through.
If you buy into the exploding Dynaplate idea, just get a bronze plate
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Old 12-10-2017, 09:51   #39
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Re: Grounding Plate for SSB

It's true that you can never be sure what all the current paths will be, but I've been reasonably successful protecting tall towers by providing a low-impedance path to a good ground. And a lead keel next to seawater is a far better ground than I could ever hope for on land.

Rule-of-thumb on land (there are exceptions) is that until a structure passes 200 feet agl, its chance of receiving a direct hit is only slightly increased compared with nearby trees, etc.

I wonder what the statistics are for a 50 foot mast on the sea?
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Old 12-10-2017, 10:01   #40
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Re: Grounding Plate for SSB

[QUOTE=a64pilot;2497647]The Dynaplate’s metal is too compacted to absorb water or it looked that way anyway, If it were that porus, it would bust very easily I would think.


Well sintered bronze bearings and bushings hold oil so why not water? It's silly to think you could see the porosity with the naked eye. Plus it's the whole point of using sintered a bronze ground plate, more surface area.
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Old 12-10-2017, 10:54   #41
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Re: Grounding Plate for SSB

There are several size DPs and I have often wondered on the smaller sizes where an electrical connection to a single 1/4" silicon bronze bolt might just be more than the path can bear. Particularly the resistance between the flat head screw and the plate. But as others have said I have never really witnessed an actual DP explosion. Have seen several boats in the yard where the lightning tracks down the side of the glass were clearly visible.

On Cbreeze I fabricated the lightning plate from 1/4" solid copper plate, 4 ea 1/2" SB flat head bolts soldered (silver bearing solder) between the bolt head and the plate. Would have used real silver solder but just could not get that big chunk of copper hot enough.

On the inside are 2 short parallel #1 AWG copper battery cables between the mast base and all 4- 1/2 bolts. Not tested to date AFAIK, but feel pretty comfortable living in the lightning capitol.

Also installed some home made surge protectors around and about to hopefully reduce damage from a nearby strike.
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Old 12-10-2017, 11:04   #42
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Re: Grounding Plate for SSB

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Well sintered bronze bearings and bushings hold oil so why not water? It's silly to think you could see the porosity with the naked eye. Plus it's the whole point of using sintered a bronze ground plate, more surface area.

Yes, all metal has microscopic paths for water or oil to populate. But a tiny amount of water like that can't possible create enough pressure to bust a bronze plate. Until i see a busted one or someone with sufficient credentials has documented it I put that theory in the "sounds plausible but it's still a myth". Sort of like the one about talking on cell phones causing petrol stations to explode. Plausible but never happens.
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Old 12-10-2017, 11:26   #43
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Re: Grounding Plate for SSB

[QUOTE=transmitterdan;2497715]Yes, all metal has microscopic paths for water or oil to populate.


Sintered metal is completly different from regular metal. Sintered bronze is a bunch of little balls pressed together into a more or less solid piece. There are passages between all the little balls. In the case of a bearing, oil is held inside the metal. In the case of a DP, water can penatrate inside the plate and have more contact area.
It makes perfect sense to me that one could blow up.
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Old 12-10-2017, 11:30   #44
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Re: Grounding Plate for SSB

Would really like to see one. I think it is an old wives tale that keeps getting repeated.
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Old 12-10-2017, 12:28   #45
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Re: Grounding Plate for SSB

See I think the whole having a larger surface area is pure marketing, it sells cause it sounds logical, but Iím betting that a flat bronze plate will perform exactly the same as an identically sized Dynaplate.
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