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#1
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Fuel tanks and SSB counterpoise.
In the process of laying up the hull I incorporated a couple hundred sq.
ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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#2
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Fuel tanks and SSB counterpoise.
Glenn Ashmore wrote in message news:JRxob.119973$sp2.25191@lakeread04...
In the process of laying up the hull I incorporated a couple hundred sq. ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? Glenn, I think you are overdoing it....I just have a copper strap from the ground of the antenna tuner to one keel bolt (external lead keel) and when I tested the syste,after installation (in New York), I got a 55 report from a ham in NW Spain. The only time Herb (Southbound II) did not hear me loud and clear was because my copper strrap had become corroded/ john N2ZOA/MM |
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#3
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Fuel tanks and SSB counterpoise.
I concur. I have internal ballast, so I drilled in and tapped in a bronze
bolt to attach the foil. I had no problems on the most recent Marion to Bermuda Race. -- Dennis Gibbons S/V Dark Lady CN35-207 email: dennis dash gibbons at worldnet dot att dot net "john s." wrote in message om... Glenn Ashmore wrote in message news:JRxob.119973$sp2.25191@lakeread04... In the process of laying up the hull I incorporated a couple hundred sq. ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? Glenn, I think you are overdoing it....I just have a copper strap from the ground of the antenna tuner to one keel bolt (external lead keel) and when I tested the syste,after installation (in New York), I got a 55 report from a ham in NW Spain. The only time Herb (Southbound II) did not hear me loud and clear was because my copper strrap had become corroded/ john N2ZOA/MM |
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#5
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Fuel tanks and SSB counterpoise.
Okay, here's another question on antenna configuration. I have just gone
through the pricing out of backstay insulators, and received the suggestion that a good, less expensive alternative would be to substitute a Kevlar backstay for the rod that I have presently, and wind a piece bare of wire around the Kevlar, up to near the masthead as an antenna. It is significantly less expensive, and the Kevlar has the advantage of being stronger and lighter than the wire. Anyone know of any disadvantages to this approach?? "john s." wrote in message om... Glenn Ashmore wrote in message news:JRxob.119973$sp2.25191@lakeread04... In the process of laying up the hull I incorporated a couple hundred sq. ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? Glenn, I think you are overdoing it....I just have a copper strap from the ground of the antenna tuner to one keel bolt (external lead keel) and when I tested the syste,after installation (in New York), I got a 55 report from a ham in NW Spain. The only time Herb (Southbound II) did not hear me loud and clear was because my copper strrap had become corroded/ john N2ZOA/MM |
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#6
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Fuel tanks and SSB counterpoise.
This doesn't address your antenna question specifically, but I have to say
that the idea of replacing a stainless wire backstay with rope just creeps me out. Sure Kevlar, in the appropriate size, could be stronger and still lighter than the wire, but its long-term durability raises some significant questions. The lifetime of stainless steel 1x19 and rod is well understood, as is the response to shock loading; I doubt that the same could be said for Kevlar. Your backstay's a pretty important rigging component - I wouldn't be inclined to screw around with it. You might also consider the long-term cost of more frequent replacement of the Kevlar, versus the cost of the wire and insulators for about a twenty-year lifetime expectancy of the SS wire and insulator combination. I'm not against Kevlar in standing rigging per se, although I'd be inclined to use it in a "supporting role", so to speak. In fact, I'm thinking of replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop with Kevlar the next time I re-rig, not so much to save weight as to keep down the chafing on my spreaders when the running backstays are housed at the after shrouds. I just wouldn't use in in a single-point-of-failure application such as the backstay. Tom Dacon "maxlynn" wrote in message news:hDVob.49689$hp5.39655@fed1read04... Okay, here's another question on antenna configuration. I have just gone through the pricing out of backstay insulators, and received the suggestion that a good, less expensive alternative would be to substitute a Kevlar backstay for the rod that I have presently, and wind a piece bare of wire around the Kevlar, up to near the masthead as an antenna. It is significantly less expensive, and the Kevlar has the advantage of being stronger and lighter than the wire. Anyone know of any disadvantages to this approach?? "john s." wrote in message om... Glenn Ashmore wrote in message news:JRxob.119973$sp2.25191@lakeread04... In the process of laying up the hull I incorporated a couple hundred sq. ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? Glenn, I think you are overdoing it....I just have a copper strap from the ground of the antenna tuner to one keel bolt (external lead keel) and when I tested the syste,after installation (in New York), I got a 55 report from a ham in NW Spain. The only time Herb (Southbound II) did not hear me loud and clear was because my copper strrap had become corroded/ john N2ZOA/MM |
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#7
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Fuel tanks and SSB counterpoise.
Composite stays are the big thing with multihull sailors but when I
checked it out for monohulls it seems that stretch will be a problem. High tech line seems to be strong enough but it evidently still stretches more than stainless wire. Tom Dacon wrote: This doesn't address your antenna question specifically, but I have to say that the idea of replacing a stainless wire backstay with rope just creeps me out. Sure Kevlar, in the appropriate size, could be stronger and still lighter than the wire, but its long-term durability raises some significant questions. The lifetime of stainless steel 1x19 and rod is well understood, as is the response to shock loading; I doubt that the same could be said for Kevlar. Your backstay's a pretty important rigging component - I wouldn't be inclined to screw around with it. You might also consider the long-term cost of more frequent replacement of the Kevlar, versus the cost of the wire and insulators for about a twenty-year lifetime expectancy of the SS wire and insulator combination. I'm not against Kevlar in standing rigging per se, although I'd be inclined to use it in a "supporting role", so to speak. In fact, I'm thinking of replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop with Kevlar the next time I re-rig, not so much to save weight as to keep down the chafing on my spreaders when the running backstays are housed at the after shrouds. I just wouldn't use in in a single-point-of-failure application such as the backstay. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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#8
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Fuel tanks and SSB counterpoise.
Okay, now that you have given your opinion on Kevlar as a backstay, how
about addressing the original question - i.e., is there any conceptual problem with wrapping a bare copper wire around it and using it for an antenna? Has anyone done this? And, oh by the way, how would you feel about using Kevlar as a substitute for 1x19 in steering cables? Would it shock you to know that many boats are using Kevlar in this highly critical application? And have been doing it successfully for over ten years now? Use as a backstay is pretty mundane by comparison. And others have been using it for a similar period as backstay material. And contrary to what you suggest, the lifetime and other properties of Kevlar are well understood. "Tom Dacon" wrote in message ... This doesn't address your antenna question specifically, but I have to say that the idea of replacing a stainless wire backstay with rope just creeps me out. Sure Kevlar, in the appropriate size, could be stronger and still lighter than the wire, but its long-term durability raises some significant questions. The lifetime of stainless steel 1x19 and rod is well understood, as is the response to shock loading; I doubt that the same could be said for Kevlar. Your backstay's a pretty important rigging component - I wouldn't be inclined to screw around with it. You might also consider the long-term cost of more frequent replacement of the Kevlar, versus the cost of the wire and insulators for about a twenty-year lifetime expectancy of the SS wire and insulator combination. I'm not against Kevlar in standing rigging per se, although I'd be inclined to use it in a "supporting role", so to speak. In fact, I'm thinking of replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop with Kevlar the next time I re-rig, not so much to save weight as to keep down the chafing on my spreaders when the running backstays are housed at the after shrouds. I just wouldn't use in in a single-point-of-failure application such as the backstay. Tom Dacon "maxlynn" wrote in message news:hDVob.49689$hp5.39655@fed1read04... Okay, here's another question on antenna configuration. I have just gone through the pricing out of backstay insulators, and received the suggestion that a good, less expensive alternative would be to substitute a Kevlar backstay for the rod that I have presently, and wind a piece bare of wire around the Kevlar, up to near the masthead as an antenna. It is significantly less expensive, and the Kevlar has the advantage of being stronger and lighter than the wire. Anyone know of any disadvantages to this approach?? "john s." wrote in message om... Glenn Ashmore wrote in message news:JRxob.119973$sp2.25191@lakeread04... In the process of laying up the hull I incorporated a couple hundred sq. ft of bronze bug screen to serve as a counterpoise. In addition two runs of 2" copper foil run down the center of the hull to the keel area. Capacitors between the foil and the keel bolts isolate any DC from getting back into the counterpoise. That is probably enough but as I am installing two aluminum tanks, I wonder how kosher it would be to tie them into the counterpoise with more capacitors. It would add another 14 sq ft of coupling area but would it be introducing other problems? Glenn, I think you are overdoing it....I just have a copper strap from the ground of the antenna tuner to one keel bolt (external lead keel) and when I tested the syste,after installation (in New York), I got a 55 report from a ham in NW Spain. The only time Herb (Southbound II) did not hear me loud and clear was because my copper strrap had become corroded/ john N2ZOA/MM |
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#9
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Fuel tanks and SSB counterpoise.
More elegant would be to use a single braid Vectran. It would take some
patience but you could feed the wire up through the core. I still see several potential problems. The first is the termination. Arimids and other high tech lines like PBO require equal tension on all fibers to maintain rated strength. Small eye splices will cut strength considerably. Special terminations that pot the fibers inside a hollow steel fitting are available but cost more than an insulator and must be factory installed. The second is stretch. No matter how high the modulus of the fiber, braided line will creep. The Kevlar 49 stays on boats like the Volvo Ocean 70's is parallel fiber inside a polyethylene cover. A backstay cost as much as a pretty decent crosscut mainsail. BTW, composite steering cables are rarely Kevlar. With the exception of Technora, arimid fibers have a tendency to chafe against each other when the line is routinely flexed under tension as around steering sheaves. Vectran and Technora are the preferred fibers for that application. maxlynn wrote: Okay, now that you have given your opinion on Kevlar as a backstay, how about addressing the original question - i.e., is there any conceptual problem with wrapping a bare copper wire around it and using it for an antenna? Has anyone done this? And, oh by the way, how would you feel about using Kevlar as a substitute for 1x19 in steering cables? Would it shock you to know that many boats are using Kevlar in this highly critical application? And have been doing it successfully for over ten years now? Use as a backstay is pretty mundane by comparison. And others have been using it for a similar period as backstay material. And contrary to what you suggest, the lifetime and other properties of Kevlar are well understood. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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#10
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Fuel tanks and SSB counterpoise.
"maxlynn" wrote in message news:Ygppb.52870$hp5.43787@fed1read04... Okay, now that you have given your opinion on Kevlar as a backstay, how about addressing the original question - i.e., is there any conceptual problem with wrapping a bare copper wire around it and using it for an antenna? Has anyone done this? The original question (Glenn's), has to do with extending the SSB foil lattice to the fuel tanks. In response to that, the consensus of the sources I've referenced for my SSB ground system is that running the foil to the tops of the tanks is a good thing to do. I've done this on my tanks, and merely laid the foil on top of the tank surface with an adhesive bonding agent (it was probably Sikaflex). I don't believe there's any need for an electrical bond, since induction should do the job nicely. Tom Dacon |
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