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#11
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SSB Antenna
Yes, I know about 'egg' insulators, I've been using them in communication
systems for 45 years myself. The Hayn insulator is 'failsafe' without wrapping the wires through loops. And it's available with eye, toggle, swage, and do-it-yourself ends. Rusty O |
#12
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SSB Antenna
I'm sure there will be a lot of serious, well-meaning naysayers for the
following, but backstay insulators have virtually become obsolete on most offshore racing boats in this area. The subsitute is a kevlar backtay with a ordinary wire(e.g., #14 stranded, tinned) either encased in the protective cover or taped to the exterior. I just completed a 1220 nmi race with this arrangement, and I know of several other boats which used the same setup. The kevlar rigging line is available in a protective pvc casing and is standard rigging material for modern race boats. It is typically stronger than the wire or rod that it replaces, much lighter, and has similar life expectancy. Oh, and the price of my new backstay was approximately half of the cost of addition of insulators to my existing rod backstay. Now I will admit that there is a difference between replacing a backstay with kevlar and replacing a shroud, but I would consult with a professional rigging service on this possibliity. This might be another alternative, and less expensive. "Rusty O" wrote in message ink.net... Hayn has just introduced a rigging insulator that has a 'failsafe' feature. If the insulating portion fails, the fitting stays together at full strength. It will loosen a bit, and you will have to tighten your turnbuckle, but it doesn't come apart. I haven't seen these yet, but their other fittings are very high quality. You can see the new insulator at http://www.hayn.com/marine/rigging/insulator.html. This may take away some of your riggers frowns. Rusty O |
#13
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SSB Antenna
In article FuM9c.17580$Ft.5252@lakeread02,
"Garland Gray II" wrote: They say there is no such thing as a stupid question, but I'm going to put that theory to a real test. I have removed a shroud from my catamaran to install insulators so it can be used as the SSB antenna. Since there is no backstay as such, a main shroud will have to do. However, I now find that the sparmaker who rigged the boat is somewhat leery of my installing two more potential failure points in a so highly loaded and critical support (of course, all are critical). He suggests using one of the lowers, but these just won't be very long. In the end I expect I'll continue with the original plan to insulate a main shroud, but a thought came to me. The shrouds are inside a thick walled plastic tube (which I had planned on removing), so I've wondered if rather than using insulators I retain the plastic tube and secure a wire...or 2 or 3... along the length of the plastic tube as the antenna? I suppose the presence of the grounded wire inside would interfere with the signal, maybe not. Would it work? The main ingerdiant for an MF/HF antenna is Electrical Length. If the antenna is to short, it will not radiate properly in the MF portion of the RF Spectrum. Yes, the autotuner will match a short antenna to the radio, but it will not help the short antenna radiate that power efficently. Longer is Better. Insulated shrouds can be effective Antennas for marine use. It will not matter if the conductive material is covered with insulative material. What wouldn't work is to string and insulated antenna wire along a grounded shroud or backstay, as the mutual coupling would destroy any RF Radiation. I really liked the Kevlar Backstay with the antenna wire, either inside, or alongside the length of the backstay. That is a very nice idea, and would work well. I might suggest that one could add to the Electrical Length, by using a spiral wrap on the antenna wire over the Kevlar Backstay, as a way to improve the RF Radiation Effecency of such a system. Bruce in alaska -- add a 2 before @ |
#14
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SSB Antenna
I've been told by riggers that the insulator's strength exceeds that of the
stay itself. Might be interesting to hear from anybody that has directly experienced a failure of an insulator. I've never heard or read of such a failure. Doug s/v Callista "Garland Gray II" wrote in message news:FuM9c.17580$Ft.5252@lakeread02... They say there is no such thing as a stupid question, but I'm going to put that theory to a real test. I have removed a shroud from my catamaran to install insulators so it can be used as the SSB antenna. Since there is no backstay as such, a main shroud will have to do. However, I now find that the sparmaker who rigged the boat is somewhat leery of my installing two more potential failure points in a so highly loaded and critical support (of course, all are critical). He suggests using one of the lowers, but these just won't be very long. In the end I expect I'll continue with the original plan to insulate a main shroud, but a thought came to me. The shrouds are inside a thick walled plastic tube (which I had planned on removing), so I've wondered if rather than using insulators I retain the plastic tube and secure a wire...or 2 or 3... along the length of the plastic tube as the antenna? I suppose the presence of the grounded wire inside would interfere with the signal, maybe not. Would it work? |
#15
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SSB Antenna
That is a good idea. I don't think I would want to use that for a shroud,
but maybe one could insert a length of 6X19 ss in the core of Warpspeed for a topping lift. It would be a pain to deal with the connection to the tail, and perhaps there'd be other problems. "maxlynn" wrote in message news:63_9c.63659$cx5.47538@fed1read04... I'm sure there will be a lot of serious, well-meaning naysayers for the following, but backstay insulators have virtually become obsolete on most offshore racing boats in this area. The subsitute is a kevlar backtay with a ordinary wire(e.g., #14 stranded, tinned) either encased in the protective cover or taped to the exterior. I just completed a 1220 nmi race with this arrangement, and I know of several other boats which used the same setup. The kevlar rigging line is available in a protective pvc casing and is standard rigging material for modern race boats. It is typically stronger than the wire or rod that it replaces, much lighter, and has similar life expectancy. Oh, and the price of my new backstay was approximately half of the cost of addition of insulators to my existing rod backstay. Now I will admit that there is a difference between replacing a backstay with kevlar and replacing a shroud, but I would consult with a professional rigging service on this possibliity. This might be another alternative, and less expensive. "Rusty O" wrote in message ink.net... Hayn has just introduced a rigging insulator that has a 'failsafe' feature. If the insulating portion fails, the fitting stays together at full strength. It will loosen a bit, and you will have to tighten your turnbuckle, but it doesn't come apart. I haven't seen these yet, but their other fittings are very high quality. You can see the new insulator at http://www.hayn.com/marine/rigging/insulator.html. This may take away some of your riggers frowns. Rusty O |
#16
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SSB Antenna
Thanks to all who replied; your answers have helped me determine that if I
go for maximum space between insulators on the lower shroud, I can get 26 or more feet, and then cover the shroud where it can be reached by crewmembers. I may be worrying too much about using the main shroud because the insulators are plenty strong, but with the wire connection being the weak point, I'd end up having 3 times as many on that shroud "Garland Gray II" wrote in message news:FuM9c.17580$Ft.5252@lakeread02... They say there is no such thing as a stupid question, but I'm going to put that theory to a real test. I have removed a shroud from my catamaran to install insulators so it can be used as the SSB antenna. Since there is no backstay as such, a main shroud will have to do. However, I now find that the sparmaker who rigged the boat is somewhat leery of my installing two more potential failure points in a so highly loaded and critical support (of course, all are critical). He suggests using one of the lowers, but these just won't be very long. In the end I expect I'll continue with the original plan to insulate a main shroud, but a thought came to me. The shrouds are inside a thick walled plastic tube (which I had planned on removing), so I've wondered if rather than using insulators I retain the plastic tube and secure a wire...or 2 or 3... along the length of the plastic tube as the antenna? I suppose the presence of the grounded wire inside would interfere with the signal, maybe not. Would it work? |
#17
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SSB Antenna
I believe that 23' is the minimum recommended for the SGC and
ICOM antenna tuners. As I mentioned earlier, I use a 23' whip fed by an ICOM antenna tuner and it works great. Doug, k3qt s/v Callista "Garland Gray II" wrote in message news:_6oac.41975$Ft.5165@lakeread02... Thanks to all who replied; your answers have helped me determine that if I go for maximum space between insulators on the lower shroud, I can get 26 or more feet, and then cover the shroud where it can be reached by crewmembers. I may be worrying too much about using the main shroud because the insulators are plenty strong, but with the wire connection being the weak point, I'd end up having 3 times as many on that shroud "Garland Gray II" wrote in message news:FuM9c.17580$Ft.5252@lakeread02... They say there is no such thing as a stupid question, but I'm going to put that theory to a real test. I have removed a shroud from my catamaran to install insulators so it can be used as the SSB antenna. Since there is no backstay as such, a main shroud will have to do. However, I now find that the sparmaker who rigged the boat is somewhat leery of my installing two more potential failure points in a so highly loaded and critical support (of course, all are critical). He suggests using one of the lowers, but these just won't be very long. In the end I expect I'll continue with the original plan to insulate a main shroud, but a thought came to me. The shrouds are inside a thick walled plastic tube (which I had planned on removing), so I've wondered if rather than using insulators I retain the plastic tube and secure a wire...or 2 or 3... along the length of the plastic tube as the antenna? I suppose the presence of the grounded wire inside would interfere with the signal, maybe not. Would it work? |
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