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12-10-2017, 11:45
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#46
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: Grounding Plate for SSB
Exactly right. It's all marketing hype.
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12-10-2017, 11:50
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#47
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Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
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Re: Grounding Plate for SSB
I have a 1/4" thick copper plate that is as big as 2 DP's and we have poor HF performance. We also have the proper insualated backstay, an 802 & 140 tuner and a pro made wire harness for the system. Must be some other problem.
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12-10-2017, 11:52
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#48
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: Grounding Plate for SSB
How far from copper plate to the tuner?
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12-10-2017, 11:59
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#49
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Registered User
Join Date: Jan 2014
Location: Panama City FL
Boat: Island Packet 32 Keel/CB
Posts: 995
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Re: Grounding Plate for SSB
I would not argue with that point. When I think about my current HF ground (1" SS tube/pipe approx 12' long maybe 2/3 below the water line) but the entire outside of the tube is inside the dry bilge. The seawater connection is in my thinking a 1" section of water maybe 8' long but only exposed to the seawater at the end. There is some capacitive coupling to the sea but that pipe typically is 4 or so inches from the interior keel surfaces. Seems to work just as well as that Dynaplate now installed on your yacht. If you don't have a CB tube or a close by thru hull then DP is a solution. The DP worked fine the question is would a copper plate also work. I have been in the boat business for over 50 years (before VHF). When all we had was HF we had Dynaplates. There were expensive then and expensive now. Used to be suspicious that the single gold plated bolt was to make you feel better about the cash you just put on the counter. Also used to come in a wooden box, more marketing BS.
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12-10-2017, 12:17
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#50
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Registered User
Join Date: Aug 2017
Location: Kentucky
Boat: 1969 Rhodes 28'
Posts: 307
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Re: Grounding Plate for SSB
Quote:
Originally Posted by a64pilot
See I think the whole having a larger surface area is pure marketing, it sells cause it sounds logical, but I’m betting that a flat bronze plate will perform exactly the same as an identically sized Dynaplate.
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I share that view. I would GUESS it provides 10-20% more conductivity than a plain plate.
It's not that difficult to test conductivity if you have a plain plate of the same size. My gut feeling is that - yes it has more surface area, but the additional area is behind already current-saturated seawater instead of where it needs to be to increase conductivity.
If somebody with a good DVM wants to do the test, I would be happy to provide step-by-step instructions.
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12-10-2017, 13:31
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#51
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Registered User
Join Date: Jan 2010
Location: Portland, Oregon, USA
Boat: 31' Cape George Cutter
Posts: 3,270
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Re: Grounding Plate for SSB
At least in theory the DynaPlate could explode from a lightning strike, just as thru-hulls can be blown out. The high current leads to instantaneous heating which turns any water into steam - a steam "explosion" results. I wouldn't obsess about this; with the power from a direct hit I would also be worried about side flashes doing damage to boat or crew, and it is pretty much a given that everything electronic or electrical would be wrecked. In short, it is likely to be a disaster in one way or another (including sinking) but it is also very unlikely to happen. And it might help to avoid it happening by installing a lightning rod or similar on the masthead to bleed off the charge that develops.
Greg
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12-10-2017, 13:43
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#52
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Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
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Re: Grounding Plate for SSB
Quote:
Originally Posted by transmitterdan
How far from copper plate to the tuner?
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About 18" of copper strip 2" wide.
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12-10-2017, 17:44
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#53
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: Grounding Plate for SSB
Quote:
Originally Posted by Guy
About 18" of copper strip 2" wide.
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Then I would say that's not the problem. Assuming the connections are free of corrosion it should be adequate.
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12-10-2017, 18:15
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#54
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Grounding Plate for SSB
Is your issue noise, not getting out, or not receiving?
I just competed my install today and have not tried anything but receive.
I was going to try to receive Chris Parker in the morning, but can’t tune any of those freqs?
Do you have to have them programmed to tune them manually?
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12-10-2017, 19:03
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#55
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: Grounding Plate for SSB
For receive only tuning doesn't do much for you. It is mainly for transmit. Don't get hyper about tuning if only trying to receive.
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12-10-2017, 19:24
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#56
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Moderator Emeritus
Join Date: Sep 2006
Posts: 4,663
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Re: Grounding Plate for SSB
Quote:
Originally Posted by transmitterdan
For receive only tuning doesn't do much for you. It is mainly for transmit. Don't get hyper about tuning if only trying to receive.
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If you have a tuner feeding the antenna (and I assume the OP does), then tuning can make a significant difference even if one is just receiving. The tuner contains inductors and capacitors that are used to match the impedance of the antenna and ground to that of the radio (50 Ohms). If the tuner can't find a good match then it may end up acting as a tuned circuit filter which may seriously reduce the strength of the received signal.
You can often hear this if you have been transmitting on one frequency (and the tuner has found a match), and then you switch to a different frequency. The signals you can hear on this new frequency may be quite attenuated until you press the "tune" button. Once a match has been found, the receive signal strength may then be considerably stronger.
Often though, the difference in signal level isn't all that noticeable.
__________________
Paul Elliott, S/V VALIS - Pacific Seacraft 44 #16 - Friday Harbor, WA
www.sailvalis.com
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12-10-2017, 19:37
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#57
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,134
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Re: Grounding Plate for SSB
Quote:
You can often hear this if you have been transmitting on one frequency (and the tuner has found a match), and then you switch to a different frequency. The signals you can hear on this new frequency may be quite attenuated until you press the "tune" button. Once a match has been found, the receive signal strength may then be considerably stronger.
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True, but there is a difference between receiving with an unmatched antenna and a MISMATCHED antenna. The former, similar to using a random length wire attached to the rx antenna post, will work pretty well over a wide frequency range. An antenna that is attached to a tuner that is tuned to some frequency other than the one you wish to listen on may be abysmal.
But guys, some of you are overthinking this ground system bit. A strap to a metal through hull or a keel bolt will really work pretty damn well. The external plate, scintered or solid, is not going to improve your signal enough to measure. Before you spend money, time and effort installing such a plate, try the other method(s0. I doubt if you will press onward if you do!
Jim N9gfT/VK4GFT m/m
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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12-10-2017, 20:58
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#58
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Registered User
Join Date: Apr 2007
Location: Pine Island, FL
Boat: Marine Trader 36 sedan
Posts: 93
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Re: Grounding Plate for SSB
I totally agree that you do not need to put any holes in your boat for a radio counterpoise. Two foil strips laid out with one in each hull will form an excellent rectangular counterpoise. I knew a guy who, on advice from a tech at Icom, attached his ground to the aluminum arch davits on the back of his boat as well as his hull ground and his radio got out better than anyone else in the Northwest Caribbean. Of course the davit was isolated from the antenna.
__________________
Sailing often into the sunset...
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12-10-2017, 21:09
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#59
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Registered User
Join Date: Apr 2016
Location: Back on dirt in Florida
Boat: Currently in between
Posts: 1,338
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Re: Grounding Plate for SSB
I love all the discussions, I feel I am learning so much. I have a better handle on what I didn't know but I still don't know what I don't know.
__________________
SV Bacchus - Living the good life!
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13-10-2017, 04:56
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#60
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Grounding Plate for SSB
This morning trying to listen to Chris Parker all I heard was a noise, similar to a Morse code type of noise.
I then tuned a news channel, or two and instead of voice, heard this noise.
It’s similar to a radio with a BFO, with it turned on.
Is there something like a BFO that I can turn off to hear the voice?
To get the radio to tune, I had to discover how to get it to the “open” mode, so I’m assuming I still have a set up problem, but don’t know where to look for the solution.
I tired clarifier, but all it did was shift the frequency of the noise higher or lower, again similar to a BFO
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