SSB Question re: Stray RF Energy - SailNet Community

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Old 03-23-2008
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SSB Question re: Stray RF Energy

After the last thread I've become re-interested in my SSB. Thanks BT, just what I need, something else to take some more of my time.

Anyway, I've been trying to transmit while we're on the hard based on Bill's thoughts that if my copper strapping goes around the boat I ought to be able to do so. No luck so far raising WLO or anyone else. Plus, when I xmit my indicator lights on my electrical panel blink, which I "understand" usually is a sign that there's a problem with the ground or antenna. Last year I definitely was able to transmit while in the water (had a couple of conversations with friends not too far away and got WLO in Mobile to confirm a radio check (though I was "weak but readable")).

So, here's my question. Is my stray RF energy which causes my lights to blink a sign that for whatever reason my counterpoise setup simply will not work unless I'm in the water, and do I have a more systemic problem with my installation?

Obviously if I still have the problem when I go in the water (in about 3 weeks) then I'll know more, but just asking to see if anyone has experience and thoughts.

Thanks,
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Old 03-23-2008
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I'd wait till the boat is back in the water before worrying about it. It may be that the hull ground won't work when out of the water. My boat has a copper plate, about 4 sq feet, on the hull as well as copper mesh in the hull layup.
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Old 03-23-2008
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Hi, Dan..

Blinking lights are usually a sign of stray RF alright, but not necessarily due to significant antenna/ground system problems. It can also be due to wiring problems, failure to use adequate RF blocking devices (ferrites, chokes, etc.), and resonant circuits. It can be caused by failure to adequately separate RF ground from the boat's DC ground. And by faulty connectors, or bad coax. It can be caused by standing waves on the coax, control, or DC power cables, especially if they are led close to other boat wiring.

I think in your stead I'd take the next 3 weeks to carefully go over your entire setup, checking the integrity of connections, correct wiring, installing ferrite chokes, etc., and also listening a lot. And, if you haven't already done so, get hold of a good power/SWR meter and put it in-line, near the transmitter.

About to take Max for a walk and to check my boat....

Cheers,

Bill
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This is a reasonably good example of a conceptually good and proven concept, the internal strapping, as it's been referred to, just may not work. That happens. Further, when you mention that "your copper strapping goes around the boat", what does that mean? A point that I wanted to make in the last thread was that an acre of copper strapping does not a proper counterpoise make if done casually.
Now, imagine you're not in your yard.
Howard Keiper
Sea Quest
Berkeley
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Old 03-23-2008
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Quote:
Originally Posted by thekeip View Post
Now, imagine you're not in your yard.
Howard Keiper
Sea Quest
Berkeley
I'm not entirely sure I know what you mean. Anyway, the strapping was installed during the boat's construction, and it circles the boat along the interior skin of the hull. Not sure how better to describe it. I also can't say that I've pulled out all the furniture, cabinetry, etc., to confirm the integrity of the installation every inch of the way.

Bill (or anyone else), is it conceivable that my RF problem is in fact caused by my not being out of the water? I understand that it could be other stuff too, but just wondering if that could be the issue. If so, I'll wait a couple of weeks before going hog wild trying to fix a problem I may not have. My strapping does connect to a keel bolt, so I am wondering seriously whether my ground setup just isn't meant to work out of the water.
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Daniel,

It's conceivable, even probable that it will work better in the water for several reasons.

However, because of the difficulty you've been having while hauled, I really suspect you've got something else going on....either one or more of the factors I mentioned, or bad timing, or maybe operator limitations??

Fact is, you should be able to hear fairly well and to make contacts while you're hauled with the setup you've described.

Boatyards are notoriously noisy, as are marinas, so a high noise level might be part of the problem.

I think that any time you spend checking out connections and wiring, and tuning the bands won't be wasted. Remember the addage from medicine: just because you have one problem doesn't mean you don't have others as well! If you spend some time checking things, than you'll know what you can eliminate as a cause -- or contributing cause -- for the difficulty you've been having.

Bill
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Old 03-23-2008
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Daniel, Does your copper ground strap connect to a copper or bronze plate on the outside of the hull? If so it isn't inconceivable that being out of the water is the problem. What power level are you using when you transmit, and does the probelm still occur with low power? If not reduce power. Research indicates the optimum power level, as related to power consumption, for reliable high frequency communication is 20 watts. So, turning the power down will likely have ony minimal negative impact on signal strength.
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Originally Posted by mjrogers View Post
Research indicates the optimum power level, as related to power consumption, for reliable high frequency communication is 20 watts. So, turning the power down will likely have ony minimal negative impact on signal strength.
And what research is that, pray tell?

Bill
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The source is somewhat circuitous. I found the information on the HFPack site. The consideration was made by comparing db gain of trasmission power with power consumption. There were some references to military radios. Sorry, but I don't recall the url. If I find it I'll post it for you.
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HF Pack yahoo forum messages 148 and 34440 reference this but are incomplete. I'l keep looking. Nonetheless, reducing transmit power could help with the flickering lights.
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