Re: [Cal_Boats] replacing antenna wiring (mike)

Hi Mike, On the antenna and GPS, there are two considerations. One it the VHF knocking out the GPS when you transmit. For that, you would like the GPS far away and high. My GPS antenna is in the cabin next to one of the windows and it works great there so I don't have experience on how sensitive they are to close field RF. The other concern is how the GPS mount will impact the antenna pattern. You would probably not want to mount the GPS on a 3 ft metal mast 18 inches away but other than that you should be fine. I would not ground the DC to the keel bolts. I really don't want my keel or other boat metal involved in any DC circuit or I might be damaging it with electrolysis. On the HF ground, probably any of the methods mentioned would work. Coper strips, coper plate under the engine, keel bolts. One might ask what happens when you don't have a good ground. You don't even need a ground to transmit on HF. I have talked more than half way around the world with an antenna that is completely on my roof. The antenna tuner is going to match into what you have and if your ground becomes part of the antenna instead of a good ground you will still transmit. But that said, I really like having a good ground where the radio is at ground potential and doesn't end up part way along the antenna. The problem is that you get shocked when you talk. It is like the radio bites you with the microphone. Very unpleasant and probably not that safe. So, if you don't have a good ground you will know it. Also, while the keel bolts will probably work, attaching to them probably ends up attaching your DC system to them. I would do either the coper strips or the coper plate, whichever was easier. In terms of length, you can't get anything long enough so you are counting on the antenna tuner. Ideally you would like the line to be close to 1/4 wavelength and not close to 1/2 wavelength to make it easier (possible) for the antenna tuner. It is very difficult (impossible) for an antenna tuner to match into 1/2 wavelength wires so that is an important point. You might also consider how you are feeding the backstay. That wire that goes from your antenna tuner to the backstay will be part of your antenna length. Consider that when you decide where to put it. This is both from an antenna length and safety perspective. Your choice of SSB rig is excellent. I have one of those tuners, have used them in the past, and they work great. I used it from an RV and not a boat though. Probably the best tuner around. (My ICOM covers the HAM band). One last thing. Check your race rules. They might require a masthead antenna. My friend who entered the transpac has two for that reason. They may even have required two and the rules might have changed, I don't know. Good luck Allen On Tue, Dec 7, 2010 at 2:56 AM, mike farrell <ve… [at] yahoo.com> wrote: > > > Thanks Allen, > I will install a 3db antenna on the stern for my standard > horizon gx2100 with AIS. If I mount the Furuno GPS antenna 3' away will that > minimize interference? > I will be installing an ICOM 710 SSB with a 130 antenna tuner. I will > use an insulated backstay antenna. Should it be 23'? Also I plan to > connect the grounds to the keel bolts of my Cal 20. I reason that the cast > steel/iron keel will provide the necessary area even tho it is painted..Is > this OK? Is 4" copper sheet the best way to go? And lastly.. Should I > connect the negative terminals on the 2 group 24 batteries also to the keel > bolts? > My Best, Mike Farrell Cal 20 #1114 > Rambler & Cal 20 #61 Coyote >

On 12/7/2010 11:18 AM, Allen Edwards wrote: > > I would not ground the DC to the keel bolts. I really don't want my > keel or other boat metal involved in any DC circuit or I might be > damaging it with electrolysis. > > Hey, Allen, expand on what you mean here. Are you concerned about the DC ground & electrolysis when you are in a marina and connected to other boats via the AC power system? Otherwise, using the keel as a DC ground doesn't seem likely to produce electrolysis problems-- there is no DC voltage differential to cause it. Look at cars--they use the car body & frame as DC ground without electrolysis (even in a salt water environment, which is what we have in Michigan at this time of year once the salt trucks hit the road). Chris Campbell

If you have your car in salt water you really do have a lot to worry about ;-) Seriously, if you ground your keel bolts and you ground your engine (which is for sure grounded) your prop is grounded. If your prop is bronze and your keel bolts are steel, you have just created a shorted out battery. You will get current due to the dissimilar metals. It won't be a very good battery and perhaps you have paint insulating the keel bolts but I personally wouldn't do it. When I first got my boat I took a voltmeter and measured the voltage from different bronze through hulls. There were small but significant voltages between them. That means the metals were slightly dissimilar and being in an electrolyte, they were a battery. A battery lasts a lot longer if you don't short it out. The bonding thing is a tradeoff between safety and killing the boat. I see there are guidelines that would have you ground everything together. I don't have an AC system, just an extension cord, so I am not worried about the safety thing any more than I am any other time I use an extension cord. Also, on a wood boat, bonding to zincs causes hydroxyl ions to form around the zinc and that east the wood. I even found using 2 zincs on my shaft was causing damage. Every boat is different so you may have different needs. One last thing, electrolysis is caused by DC, not AC. The problem with boats in the slip is if someone is putting a DC current into the dock ground and your boat is in the path. Allen On Tue, Dec 7, 2010 at 9:18 AM, Chris <cc… [at] lsnm.org> wrote: > > > On 12/7/2010 11:18 AM, Allen Edwards wrote: > > > > I would not ground the DC to the keel bolts. I really don't want my keel or > other boat metal involved in any DC circuit or I might be damaging it with > electrolysis. > > > Hey, Allen, expand on what you mean here. Are you concerned about the DC > ground & electrolysis when you are in a marina and connected to other boats > via the AC power system? Otherwise, using the keel as a DC ground doesn't > seem likely to produce electrolysis problems-- there is no DC voltage > differential to cause it. Look at cars--they use the car body & frame as DC > ground without electrolysis (even in a salt water environment, which is what > we have in Michigan at this time of year once the salt trucks hit the road). > > Chris Campbell > > >

Thank you Allen, I really appreciate your intelligent response. I am a complete novice in radio and I have a basic understanding of what is needed but not specifics. I will fit a masthead antenna for vhf as is required by the Rules, You are right! However I believe a stern mounted 3db is so close, that the weight and coax in the mast is a negative factor. That said.. don't make waves with the boat scrutineers who often have no sense of humor. The instructions with the Icom call for 100 sq foot counterpoise which is impossible in a Cal 20. Thanks once more for your reinsurance. My Best, Mike From: Allen Edwards <al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com Sent: Tue, December 7, 2010 8:18:20 AM Subject: Re: [Cal_Boats] replacing antenna wiring (mike) Hi Mike, On the antenna and GPS, there are two considerations. One it the VHF knocking out the GPS when you transmit. For that, you would like the GPS far away and high. My GPS antenna is in the cabin next to one of the windows and it works great there so I don't have experience on how sensitive they are to close field RF. The other concern is how the GPS mount will impact the antenna pattern. You would probably not want to mount the GPS on a 3 ft metal mast 18 inches away but other than that you should be fine. I would not ground the DC to the keel bolts. I really don't want my keel or other boat metal involved in any DC circuit or I might be damaging it with electrolysis. On the HF ground, probably any of the methods mentioned would work. Coper strips, coper plate under the engine, keel bolts. One might ask what happens when you don't have a good ground. You don't even need a ground to transmit on HF. I have talked more than half way around the world with an antenna that is completely on my roof. The antenna tuner is going to match into what you have and if your ground becomes part of the antenna instead of a good ground you will still transmit. But that said, I really like having a good ground where the radio is at ground potential and doesn't end up part way along the antenna. The problem is that you get shocked when you talk. It is like the radio bites you with the microphone. Very unpleasant and probably not that safe. So, if you don't have a good ground you will know it. Also, while the keel bolts will probably work, attaching to them probably ends up attaching your DC system to them. I would do either the coper strips or the coper plate, whichever was easier. In terms of length, you can't get anything long enough so you are counting on the antenna tuner. Ideally you would like the line to be close to 1/4 wavelength and not close to 1/2 wavelength to make it easier (possible) for the antenna tuner. It is very difficult (impossible) for an antenna tuner to match into 1/2 wavelength wires so that is an important point. You might also consider how you are feeding the backstay. That wire that goes from your antenna tuner to the backstay will be part of your antenna length. Consider that when you decide where to put it. This is both from an antenna length and safety perspective. Your choice of SSB rig is excellent. I have one of those tuners, have used them in the past, and they work great. I used it from an RV and not a boat though. Probably the best tuner around. (My ICOM covers the HAM band). One last thing. Check your race rules. They might require a masthead antenna. My friend who entered the transpac has two for that reason. They may even have required two and the rules might have changed, I don't know. Good luck Allen On Tue, Dec 7, 2010 at 2:56 AM, mike farrell <ve… [at] yahoo.com> wrote: >Thanks Allen, > I will install a 3db antenna on the stern for my standard horizon >gx2100 with AIS. If I mount the Furuno GPS antenna 3' away will that minimize >interference? > I will be installing an ICOM 710 SSB with a 130 antenna tuner. I will use >an insulated backstay antenna. Should it be 23'? Also I plan to connect the >grounds to the keel bolts of my Cal 20. I reason that the cast steel/iron keel >will provide the necessary area even tho it is painted..Is this OK? Is 4" copper >sheet the best way to go? And lastly.. Should I connect the negative >terminals on the 2 group 24 batteries also to the keel bolts? > > My Best, Mike Farrell Cal 20 #1114 >Rambler & Cal 20 #61 Coyote

But Chris, The only metal that I can use for a counterpoise is the keel, I have no metal thru hulls and no engine. Icom says if I do not ground everything in the same place there will be a voltage difference which will produce electrolysis. I propose to ground both group 24 batteries and the SSB and the 130 antenna tuner to ONE keel bolt. It worked well on a SC 27 we sailed in the 88 Pac Cup as we had no engine and no metal water tanks etc. I do not seek 6000 mile range as I believe a compromise is OK. My Best, Mike From: Chris <cc… [at] lsnm.org> To: Ca… [at] yahoogroups.com Sent: Tue, December 7, 2010 9:18:30 AM. Subject: Re: [Cal_Boats] replacing antenna wiring (mike) On 12/7/2010 11:18 AM, Allen Edwards wrote: > > >I would not ground the DC to the keel bolts. I really don't want my keel or >other boat metal involved in any DC circuit or I might be damaging it with >electrolysis. > > >Hey, Allen, expand on what you mean here. Are you concerned about the DC ground >& electrolysis when you are in a marina and connected to other boats via the AC >power system? Otherwise, using the keel as a DC ground doesn't seem likely to >produce electrolysis problems-- there is no DC voltage differential to cause >it. Look at cars--they use the car body & frame as DC ground without >electrolysis (even in a salt water environment, which is what we have in >Michigan at this time of year once the salt trucks hit the road). Chris Campbell

On 12/7/2010 1:39 PM, Allen Edwards wrote: > > > One last thing, electrolysis is caused by DC, not AC. The problem > with boats in the slip is if someone is putting a DC current into the > dock ground and your boat is in the path. Yeah, that's what I meant--the AC system connects your boat with others, often in unanticipated and unintended ways. My boats don't have AC systems but we have all read and heard the horror stories. Chris Campbell

On 12/7/2010 2:12 PM, mike farrell wrote: > But Chris, > The only metal that I can use for a counterpoise is the > keel, I have no metal thru hulls and no engine. Icom says if I do > not ground everything in the same place there will be a voltage > difference which will produce electrolysis. I propose to ground both > group 24 batteries and the SSB and the 130 antenna tuner to ONE keel > bolt. Seems to me that ought to work just fine as long as you're not connected with a line of boats in the marina via your shore-power cord. Simple boats are a blessing, aren't they? Chris Campbell

Thank you! I will be offshore when I power up the SSB. My best, Mike From: Chris <cc… [at] lsnm.org> To: Ca… [at] yahoogroups.com Sent: Tue, December 7, 2010 11:34:32 AM Subject: Re: [Cal_Boats] replacing antenna wiring (mike) On 12/7/2010 2:12 PM, mike farrell wrote: >But Chris, > The only metal that I can use for a counterpoise is the keel, I >have no metal thru hulls and no engine. Icom says if I do not ground everything >in the same place there will be a voltage difference which will produce >electrolysis. I propose to ground both group 24 batteries and the SSB and the >130 antenna tuner to ONE keel bolt. > Seems to me that ought to work just fine as long as you're not connected with a line of boats in the marina via your shore-power cord. Simple boats are a blessing, aren't they? Chris Campbell

Nothing is going to happen to your keel or boat in the time it takes for your races. The electrolysis issue is over years and if you don't have an engine or through hulls, and if your keel in encapsulated, you should not have a problem even over a long time. I really should have said that originally, sorry. Given your situations I would not hesitate to use the keel as the ground for the radio. I had an expression I used to tell people when we were designing stuff. Anything can be declared your ground reference, but only one thing. Everything else is removed from ground. So in your case, I might declare the keel bolt you ground and connect everything else that needs to be connected to that point. The radio ground lead to that point, the antenna tuner ground to that point. It is really not clear to me that the battery needs to tie to that directly but I don't think it would hurt as it will be electrically connected through the radio. For my HAM station, I had a large aluminum plate, like 2 feet by 2 feet and that was my ground. All the radio's were grounded to it, the antenna tuner was, and two "wires" one a 2 inch coper foil and the other a 1 inch braid went to an 8 foot rod into the ground. The issue was my "shack" was on the second floor. Before I put in this arrangement the mic would bit my lip when it talked. Alternatively, you could do something similar and just have a braid going to the keel bolt. You just need to pick your reference point. Allen On Tue, Dec 7, 2010 at 11:00 AM, mike farrell <ve… [at] yahoo.com> wrote: > > > Thank you Allen, > I really appreciate your intelligent response. I am a > complete novice in radio and I have a basic understanding of what is needed > but not specifics. I will fit a masthead antenna for vhf as is required by > the Rules, You are right! However I believe a stern mounted 3db is so > close, that the weight and coax in the mast is a negative factor. That > said.. don't make waves with the boat scrutineers who often have no sense of > humor. The instructions with the Icom call for 100 sq foot counterpoise > which is impossible in a Cal 20. Thanks once more for your reinsurance. > My Best, Mike > > ------------------------------ > *From:* Allen Edwards <al… [at] PaloAltoPhoto.com> > *To:* Ca… [at] yahoogroups.com > *Sent:* Tue, December 7, 2010 8:18:20 AM > *Subject:* Re: [Cal_Boats] replacing antenna wiring (mike) > > > > Hi Mike, > > On the antenna and GPS, there are two considerations. One it the VHF > knocking out the GPS when you transmit. For that, you would like the GPS > far away and high. My GPS antenna is in the cabin next to one of the > windows and it works great there so I don't have experience on how sensitive > they are to close field RF. > > The other concern is how the GPS mount will impact the antenna pattern. > You would probably not want to mount the GPS on a 3 ft metal mast 18 inches > away but other than that you should be fine. > > I would not ground the DC to the keel bolts. I really don't want my keel or > other boat metal involved in any DC circuit or I might be damaging it with > electrolysis. > > On the HF ground, probably any of the methods mentioned would work. Coper > strips, coper plate under the engine, keel bolts. One might ask what > happens when you don't have a good ground. You don't even need a ground to > transmit on HF. I have talked more than half way around the world with an > antenna that is completely on my roof. The antenna tuner is going to match > into what you have and if your ground becomes part of the antenna instead of > a good ground you will still transmit. But that said, I really like having > a good ground where the radio is at ground potential and doesn't end up part > way along the antenna. The problem is that you get shocked when you talk. > It is like the radio bites you with the microphone. Very unpleasant and > probably not that safe. So, if you don't have a good ground you will know > it. Also, while the keel bolts will probably work, attaching to them > probably ends up attaching your DC system to them. I would do either the > coper strips or the coper plate, whichever was easier. > > In terms of length, you can't get anything long enough so you are counting > on the antenna tuner. Ideally you would like the line to be close to 1/4 > wavelength and not close to 1/2 wavelength to make it easier (possible) for > the antenna tuner. It is very difficult (impossible) for an antenna tuner > to match into 1/2 wavelength wires so that is an important point. You might > also consider how you are feeding the backstay. That wire that goes from > your antenna tuner to the backstay will be part of your antenna length. > Consider that when you decide where to put it. This is both from an > antenna length and safety perspective. > > Your choice of SSB rig is excellent. I have one of those tuners, have used > them in the past, and they work great. I used it from an RV and not a boat > though. Probably the best tuner around. (My ICOM covers the HAM band). > > One last thing. Check your race rules. They might require a masthead > antenna. My friend who entered the transpac has two for that reason. They > may even have required two and the rules might have changed, I don't know. > > Good luck > > Allen > > > > On Tue, Dec 7, 2010 at 2:56 AM, mike farrell <ve… [at] yahoo.com>wrote: > >> >> >> Thanks Allen, >> I will install a 3db antenna on the stern for my standard >> horizon gx2100 with AIS. If I mount the Furuno GPS antenna 3' away will that >> minimize interference? >> I will be installing an ICOM 710 SSB with a 130 antenna tuner. I will >> use an insulated backstay antenna. Should it be 23'? Also I plan to >> connect the grounds to the keel bolts of my Cal 20. I reason that the cast >> steel/iron keel will provide the necessary area even tho it is painted..Is >> this OK? Is 4" copper sheet the best way to go? And lastly.. Should I >> connect the negative terminals on the 2 group 24 batteries also to the keel >> bolts? >> My Best, Mike Farrell Cal 20 #1114 >> Rambler & Cal 20 #61 Coyote >> > > > >