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  #1  
Old 12-10-2005, 10:17 AM
Russ L Russ L is offline
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Join Date: Jun 2005
Location: Vancouver Island
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Default dipole

Thanks for jumping into the discussion Renoir and good points.
So, for Bill's situation, with the pieces in place he will have a quasi inverted dipole. A local live-aboard HAM uses an inverted dipole on his sloop. I have learned that if you take a challenge into a meeting of HAMs you can come away with almost as many opinions as there are members attending.
What effect will a furling gear have on the forestay leg? Should the forward lead be "earth"?
He can be transmitting very easily & cheaply with the current set-up. I believe he should try your suggestion first.
Cheers, Russ
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  #2  
Old 12-10-2005, 03:32 PM
Russ L Russ L is offline
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Default whoa

For Bill's rig, in the most recent discussion, we have been assuming a plastic or wood boat and unbonded rig.
We do not want to 'connect' the ends of a dipole antennea together ...

Cheeers, Russ
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  #3  
Old 12-10-2005, 05:05 PM
Renoir Renoir is offline
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Location: Bremerton, WA
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Default Dipole or loop

One cannot truly view a bonded rigging as a dipole with the ends shorted. You just have to try it first on the different bands to see what is the impedance presented. In some cases it just works great, in others not. Sometimes one merely has to install a knift switch in the one of the bond wires to open the while transmitting and close it in storms.
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  #4  
Old 12-12-2005, 07:13 PM
billknny billknny is offline
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Default My head hurts!

Gee, I thought I was asking a simple question! NowI know the reason that I became a chemical engineer instead of an electrical engineer!

Let's see if I have understood the things discussed.

With an insulator at the center of the spring stay, I can run a coax from the antenna tuner up to the insulator where I connect it to each side of the insulated spring stay with a balun (had to look that up, but still don't really have a good feel about what it might look like!). This makes a large dipole antenna witht he main mast as one leg and the mizzen as the other.

It sounds like there is a difference of opinian on the effects of the lightning gound on the mast, which theoretically would ground the two ends of the dipole, which even I know would not be a great idea!

All this might be of theoretical interest since it sounds like the lead of the coax can't go back to the mizzen along the spring stay. If it deviates much from that, it will interfer with my mizzen staysail, which I am loath to lose the use of!
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