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 Vhf grounding		  New Topic  Topic Locked
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istion
Deckhand

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Canada
14 Posts
Initially Posted - 02/24/2017 :  16:11:37  Show Profile
I just learned that my VHF probably is getting poorer reception and distance because I don't have it properly grounded period

Can somebody tell me how to do this. Any advice is appreciated
Proud Third owner of C250 wk 2004 Dubhe hull 745

kjk
1st Mate

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USA
91 Posts
Response Posted - 02/25/2017 :  08:53:45  Show Profile
Are you sure its attached to a working antenna?
Kevin J. Kiely
Rockport, MA
1999WK
Hull # 407
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Steve Milby
Past Commodore

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USA
5851 Posts
Response Posted - 02/25/2017 :  09:39:57  Show Profile
I believe that, on an outboard powered boat, the ground is usually just connected to the negative battery terminal. That's the way I did it on my C25, and it worked well. When you think about it, a handheld vhf radio isn't grounded to a bronze through hull, and it works.

Maybe the ground connection is dirty or corroded or just loose.
Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore
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Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts
Response Posted - 02/25/2017 :  10:40:35  Show Profile
I've been led to understand that VHF radios don't require actual grounding as do SSB and some others, and I've never grounded mine. (The negative side of the battery in a DC system is often referred to as "ground", it's really just the other side of the circuit--not like the ground in an AC system.

In my experience, the most common cause of poor transmission and reception is corrosion and/or gunk in the antenna connection at the radio. Put some alcohol on a fine-textured Scotchbrite pad and rub it on the threads on the radio and in the cable connector, being careful not to bend the wire in the middle of the connector. See if that helps.
Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge
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islander
Master Marine Consultant

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USA
3992 Posts
Response Posted - 02/25/2017 :  10:41:09  Show Profile
If it's not a portable radio it should be grounded to the ground bus bar or terminal behind your switch panel. The positive should be connected to a fused switch or a POS. Lead. The antenna is grounded to radio through the coax cable..Dave is right that what is called a ground is just the neg. Side of the circuit
Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound


Edited by - islander on 02/25/2017 11:00:16
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Voyager
Master Marine Consultant

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USA
5231 Posts
Response Posted - 02/26/2017 :  08:25:07  Show Profile
Most boats are made of fiberglass and don't have a through hull grounding plate. Typical size would be 12"x12" or larger. Most boats' VHF radios work pretty well, however, I hear spark plug interference and alternator whine often enough from other boats.
I'd say that the most important issues are (1) corrosion on the threads of the connectors, (2) bad crimp between the connector body and the cable shield (ground) wire, (3) intermittent or corroded center conductor between the connector and the receptacle, (4) electrical interference (engine & alternator). With on average 3 or more connectors between the radio (1) and the antenna (2), add a barrel at the mast and that's 4. That's where I'd look first.
Fwiw, you could connect 20ft of #16 wire to the radio's ground lead, connect a large sheet of tin foil to the other and toss it overboard. If your radio works better then you'd know.
Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain — Milford, CT
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glivs
Admiral

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USA
822 Posts
Response Posted - 02/26/2017 :  08:53:17  Show Profile
Reading through the responses it appears we have a communication/ terminology issue. A fixed VHF of course has a pos. and neg. lead in addition to the antenna. Most, in addition, have a separate screw that is recommended to be attached to "ground". I believe it is this connection that is in question. Descriptions of how to wire this are typically vague although as already noted, I believe can be optionally connected to the negative side of your DC system.
Gerry & Leslie; Malletts Bay, VT
"Great Escape" 1989 C-25 SR/WK #5972
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glivs
Admiral

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USA
822 Posts
Response Posted - 02/26/2017 :  08:55:10  Show Profile
Reading through the responses it appears we have a communication/ terminology issue. A fixed VHF of course has a pos. and neg. lead in addition to the antenna. Most, in addition, have a separate screw that is recommended to be attached to "ground". I believe it is this connection that is in question. Descriptions of how to wire this are typically vague although as already noted, I believe can be optionally connected to the negative side of your DC system.
Gerry & Leslie; Malletts Bay, VT
"Great Escape" 1989 C-25 SR/WK #5972
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Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts
Response Posted - 02/26/2017 :  09:20:42  Show Profile
quote:
Originally posted by Voyager

...Most boats' VHF radios work pretty well, however, I hear spark plug interference and alternator whine often enough from other boats...
...perhaps because they grounded their radios to a bonding system or the inboard engine and thereby to the water. West Marine, in discussing grounding systems (AC, DC, RF, and lightning protection) says this regarding radios:
quote:
Your VHF doesn't need to use the ocean as a counterpoise, so here we are dealing only with the ground needed for your HF/SSB radio...
Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge
Edited by - Stinkpotter on 02/26/2017 09:25:10
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Voyager
Master Marine Consultant

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USA
5231 Posts
Response Posted - 02/27/2017 :  15:04:07  Show Profile
All that said, therefore, the three most important things to check are connections, connections, connections.
Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain — Milford, CT
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Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.