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Old 16-11-2006, 19:52   #16
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Hi, John...

It's good practice to ground to a single point, rather than have multiple grounding points. This is true with DC, and it's a good idea with RF as well.

It's fine to have multiple radials, copper strips, etc., but they should be grounded ONLY at the tuner/balun. Opinion is divided on whether or not to ground the radio itself to the RF ground; I don't do it and don't think it's necessary. The problem to be avoided, here, is one of ground loops....caused by multiple grounding points.

I think I'd try going with the copper strips...the more and longer the better...all tied to a common point (the tuner/balun). Insulated radial wires work very well also, either "tuned" (e.g., 1/4 wavelength long at the desired operating frequency) or random. More relatively shorter radials, foil, etc. rather than fewer longer radials, foil, etc. are better.

I think I'd start with the foil and, if you experience any problem tuning up on any band, just add a radial or two cut to 1/4 wavelength. The formula is Length in Feet = 234/freq in MHz. Example: for the 8 MHz marine band the tuned radial would be 234/8 = 29.25 feet long. This same radial would be 1/2 wavelength long on the 16 MHz marine band, and would work well, too.

The 15' of 14g wire you tested with is a bit short! I'd use a wire at least 30' long and, if you want to optimize for use on the lower bands, maybe 40-50' long if you have room.

Bill
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Old 16-11-2006, 20:01   #17
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Damp Lines

Hello Sailor,

Sorry, I missed your query.

Yeah, I used to worry about that, too. As you know, hams say they can tune up a wet string :-))

In practice, though, I've never noticed any effect. The Dacron halyard length from the top of the mast to the top of the antenna is sufficiently long to provide good insulation.

At the bottom end, though, it's length is quite short. I recently substituted a longish black ribbed insulator for the little black egg insulator I'd been using, not because I ever experienced any detuning that I noticed, but just for good measure! Like throwing salt over your shoulder :-))

Bill
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Old 17-11-2006, 05:22   #18
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Hi Bill

Thanks for the info. All sounds good. I now have things adjusted and will try and see what I am heard like on Cruzhiemers this am. [Yesterday, a boat in GA heard me just fine....that was using the coax cable run to the topping lift, outer braid ground to the boom.]

Clarification ..the 15ft of 14g wire is connecting my antenna (the 40+ft topping lift) to the tuner. I took a short piece of coax and connect the wire to the center conductor, that's it. Seems to tune fine. Is this ok?

Thanks

John
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Old 17-11-2006, 06:33   #19
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Yep, that'll do it.

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Old 17-11-2006, 07:34   #20
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Hello John,
Glad to see yer using multable sources for info. How is it comming? I tried 6.334Mhz last night a coule of times but couldn't raise you. I try it again later if you don't mind.
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Old 17-11-2006, 10:55   #21
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Aloha John et al,

I really appreciate the instruction this thread is providing. I'm not the licensing police but isn't some type of HAM license required to transmit on an SSB? I asumed that it was that's why I'm pursuing the proper licensing before installing a unit. Regards, JohnL

"I really would appreciate some help with this. LDG is a very well respected tuner company in the HAM world...I am not a HAM...just did some research."
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Old 17-11-2006, 12:04   #22
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"I'm not the licensing police but isn't some type of HAM license required to transmit on an SSB?"

You need a ham license to transmit on ham bands and you need a marine license to transmit on the marine bands. I don't mean to sound flippant but that the truth of it.
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Old 17-11-2006, 12:19   #23
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Oops?

Good thing you're not the radio police, either, 'cuz 6334 is not an authorized frequency except for:

"Coast stations, wide-band and A1A Morse telegraphy, facsimile, special and data transmission systems and direct-printing telegraphy systems."

I'm sure you meant, e.g., 6224, n'est pas?

Bill
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Old 17-11-2006, 12:28   #24
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Aloha Coaster,
Isn't that interesting! So a HAM license does not authorize you to transmit on marine bands of a SSB?
I am old, ignorant and confused.
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Old 17-11-2006, 12:40   #25
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John,

You're not old and confused. It's just all that hooch you've been mixing with the coconut and pineapple juice out there in Hawaii :-))

A ham license allows you to transmit on the ham bands. Period.

A marine license allows you to transmit on the marine bands. Period.

An aircraft license allows you to transmit on the aircraft bands. Period.

There....that's not so difficult, is it?

Bill
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Old 17-11-2006, 14:07   #26
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Afraid thats right John. It's a money thing I think - fees regestration, classes equipment ...... Kinda like boats.
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Old 17-11-2006, 14:13   #27
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The licensing police are at:fcc.gov. The application is quite straight forward but does not include any information on installing marine SSB's, it focuses on where to send your $160.

I do actually have quite a variety of technical literature from ICOM (the M-700 manual, AT-130 manual and ICOM's little treatise on grounding), LDG and other sources. On some issues they conflict, none have info specific to exactly what I am doing. Thus the post here since I knew some knowledgable people hung here (and elsewhere).

My setup is working perfectly fine, just like to tweak it and get it the best it can be.

Bill - info was very helpful, have made a few changes and seems to be working even better.

ALAN - we can coord on Renegades...easier there.

Thanks to all.

Mahalo
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Old 17-11-2006, 14:56   #28
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John,

Glad it's working for you.

There's a bunch of stuff in the Icom literature and in many other "texts" re: grounding, and it's mostly all wrong. Garbage, repeated by one "authority" after another until -- as Johnathan Winters used to say -- "you get to believing your own stuff!"

Perhaps most egregious is the now urban-legend credo that you've gotta use 3-4" copper straps, and ground to everything: thru hull, keel, water tanks, etc. And, the supposed reasoning for this is that "RF travels on the surface of conductors, so you've gotta provide the greatest surface area possible". I even recall that in one of these "bibles" -- Icom, I think -- there's the statement that you can't use regular wire for RF grounding.

Well, it's all poppycock. RF does, indeed, travel on the surface of conductors, but if you arrange the conductor(s) properly you don't need a huge surface area. Wire can work just fine. Consider the lowly dipole which is one of the most effective antennas you can put on a boat. It is completely self-contained, requiring no external ground of any kind. It is a balanced antenna, with the radiating portion exactly the same length and size (usually wire) as the "counterpoise" side.

REFLECT ON THAT FOR A MOMENT: a dipole is a very effective all-wire antenna which doesn't require any kind of external grounding. At all. No copper straps. No water tanks. No thru-hulls. No grounding plates. No "100 square feet of surface area", the oft-parroted answer given when someone asks how much copper is required.

Consider also that RF cannot travel more than a very few inches through seawater. Why, then, would it be a good idea to pump RF energy deep into the sea, via a groundplate some 4-6' underwater? Of course it's not a good idea....it's just what everyone has said and repeated from what others have said. A much better RF grounding or counterpoise system consists of radials (insulated wire is fine) arranged just belowdecks. Or, like I use, aluminum toerails and the lifeline/pushpit/pulpit complex.

There's lots written about this on other Boards: SSCA, the MM Ham Net board, etc.

Time to climb down off my soapbox.

Apologies to Icom, Gordon West, Marti Brown, and all the others who've trumpeted the call of the Original Marine RF Grounding Expert -- whoever he/she was -- all these years. It's certainly the safe thing to do, because there are so many "experts" who've said this is the way to do it. And because it removes the .000001% chance of someone, somewhere, possibly getting an RF burn.

Hams who know a thing or three about feeding random length wires, and their counterpoise requirements, know better, as do others who've broken ranks and decided to put up truly effective antenna systems on their boats.

Bill
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Old 17-11-2006, 15:45   #29
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Too many Mai Tais.

Thanks for the information. Maybe licensing would be better served on a different thread. Mind if I do that?

New question. So I don't need a big copper ground plate on the outside of the hull?

Kind Regards,
JohnL
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Old 17-11-2006, 16:25   #30
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JohnL,

Absolutely not. Waste of money. Extra drag on your hull.

B.
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