I got this link (from my Ham Radio Club) for a very interesting article about grounding a sailboat for RF. Hope it helps someone as much as it did me.... Ron/Talisman/KA5HZV
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BE VERY CAREFUL WITH "GROUNDS"
Ron, this article does not cover this subject well if at all. I have seen some boats which had the RF ground directly connected to the bonding system in the boat. This RF ground eventually was connected to the DC ground and sometimes to the AC ground. One of my neighbors boats was miswired this way and it ate my zincs, then the prop and then the shaft. I had a $5000 haulout this last summer because of that. Insurance will not cover any of that either - pretty much useless except for a major catastrophe. My recommendation is to use a capacitance RF ground isolating system. Look it up to find details. Ron, please make sure that the bonding system is isolated from the other grounds in your boat.
Ron, this article does not cover this subject well if at all. I have seen some boats which had the RF ground directly connected to the bonding system in the boat. This RF ground eventually was connected to the DC ground and sometimes to the AC ground. One of my neighbors boats was miswired this way and it ate my zincs, then the prop and then the shaft. I had a $5000 haulout this last summer because of that. Insurance will not cover any of that either - pretty much useless except for a major catastrophe. My recommendation is to use a capacitance RF ground isolating system. Look it up to find details. Ron, please make sure that the bonding system is isolated from the other grounds in your boat.
To clarify Patrick's point...
We tend to use the term 'ground' generically, but Patrick's pointing out that there are two separate, distinct kinds of 'ground'. One is the -12V ground to which our rigs, tanks, engine etc. are tied to. (The 'green wire' ground...). Ron's subject is about the other kind of ground, the RF ground plane, which is essentially half of an antenna system for SSB radios. It is very common for folks to tie these two 'grounds' together, not only because they might believe them to be the same thing, but also because the thinking is that using the -12V ground will automatically tie together all those hunks of metal, thereby physically enlarging and therefore improving the RF ground plane. One consequence of this is that the 12V electrical system is invited into the RF ground plane, and vice versa. Examples of this are when one keys the mike and watches all the DC panel LEDs light up (RF getting into the 12V system) or the 12V reefer motor kicking on & distorting the transmitted SSB signal (DC hash intruding on the SSB). ABYC standards have the AC and DC grounds connected for safety reasons (altho' this is still debated widely), and this can further affect things if the two 'grounds' are confused. However, it sounds to me like Patrick's damage was caused by an AC wiring error well beyond an incorrect SSB installation, since the SSB on his neighbor's boat was probably unpowered 99+% of the time. Patrick, have you subsequently installed a galvanic isolator? They're not much money (maybe 1% of your repair bill), easily installed and good insurance. Jack
We tend to use the term 'ground' generically, but Patrick's pointing out that there are two separate, distinct kinds of 'ground'. One is the -12V ground to which our rigs, tanks, engine etc. are tied to. (The 'green wire' ground...). Ron's subject is about the other kind of ground, the RF ground plane, which is essentially half of an antenna system for SSB radios. It is very common for folks to tie these two 'grounds' together, not only because they might believe them to be the same thing, but also because the thinking is that using the -12V ground will automatically tie together all those hunks of metal, thereby physically enlarging and therefore improving the RF ground plane. One consequence of this is that the 12V electrical system is invited into the RF ground plane, and vice versa. Examples of this are when one keys the mike and watches all the DC panel LEDs light up (RF getting into the 12V system) or the 12V reefer motor kicking on & distorting the transmitted SSB signal (DC hash intruding on the SSB). ABYC standards have the AC and DC grounds connected for safety reasons (altho' this is still debated widely), and this can further affect things if the two 'grounds' are confused. However, it sounds to me like Patrick's damage was caused by an AC wiring error well beyond an incorrect SSB installation, since the SSB on his neighbor's boat was probably unpowered 99+% of the time. Patrick, have you subsequently installed a galvanic isolator? They're not much money (maybe 1% of your repair bill), easily installed and good insurance. Jack
I had a galvanic isolater
It only works to protect relatively small stray voltages from causing a problem. The electrical surveyer I spoke to told me of another boat in my marina which had his outdrives completely destroyed by electrolysis. He also related a story where a dock which had a common meter was feeding 30 amps into the water due to miswiring. Nobody noticed it because of the fact that the meter was monitoring the entire dock and 30 amps was such a small percentage.
It only works to protect relatively small stray voltages from causing a problem. The electrical surveyer I spoke to told me of another boat in my marina which had his outdrives completely destroyed by electrolysis. He also related a story where a dock which had a common meter was feeding 30 amps into the water due to miswiring. Nobody noticed it because of the fact that the meter was monitoring the entire dock and 30 amps was such a small percentage.
Ron,
Thank you for that link. I printed out the book. The stack of paper is an inch high. Then I played with the printer (new) and learned how to print on both sides. It was a snap! Oh well, Thanks again.
Thank you for that link. I printed out the book. The stack of paper is an inch high. Then I played with the printer (new) and learned how to print on both sides. It was a snap! Oh well, Thanks again.
Ed -
Sounds interesting. I've often thought about using the topping lift to pull a wire up for temporary use. Also considering a SS whip on the back rail going into a tuner. If you are going to use the lifelines port and stbd, you may find that the ends are a little too close. Let me know how it goes. And get that license! Gregg
Sounds interesting. I've often thought about using the topping lift to pull a wire up for temporary use. Also considering a SS whip on the back rail going into a tuner. If you are going to use the lifelines port and stbd, you may find that the ends are a little too close. Let me know how it goes. And get that license! Gregg
Another antenna
We have used a whip (Hustler mobile) antenna attached to our stern pulpit for 6 years in the Sea of Cortez. We also have hard-drawn copper antenna wire running from the mast top to the stern pulpit (insulators at both ends) which is not in the way of the main sail. Both antennas run through a manual antenna tuner (although an automatic would work). We work ham radio e-mail daily back to the east coast and world-wide coverage on 20 meters easily. 1:1 SWR due to the tuner. Cost-cheap. Effective, absolutely. Jack Swords WA6WTH...get that ham license!!!
We have used a whip (Hustler mobile) antenna attached to our stern pulpit for 6 years in the Sea of Cortez. We also have hard-drawn copper antenna wire running from the mast top to the stern pulpit (insulators at both ends) which is not in the way of the main sail. Both antennas run through a manual antenna tuner (although an automatic would work). We work ham radio e-mail daily back to the east coast and world-wide coverage on 20 meters easily. 1:1 SWR due to the tuner. Cost-cheap. Effective, absolutely. Jack Swords WA6WTH...get that ham license!!!
Coax to antenna
My antenna is an insulated backstay. I haven't bought the radio yet so I am looking for guidance. I have read that an unjacketed wire should be used from the tuner to the antenna. Ed is apparently using coax to the antenna. Is that because of the inverted V? Should I consider coax to the backstay antenna which is just a long wire?
My antenna is an insulated backstay. I haven't bought the radio yet so I am looking for guidance. I have read that an unjacketed wire should be used from the tuner to the antenna. Ed is apparently using coax to the antenna. Is that because of the inverted V? Should I consider coax to the backstay antenna which is just a long wire?
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