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btrayfors · 10-12-2007, 15:16

Hey, Don...

You've just been playing in the wrong sandbox all these years :-)

Just kidding. I think we've both been foolin' with antennas for a very long time.

What I was reacting to was your note about a horizontal dipole being best if rigged high enough. Clearly, that's not possible on a sailboat. More importantly, it just ain't so.

The vertical dipole is such a killer DX antenna because, when rigged LOW to the ground, it's vertical radiation is very low. It has a huge lobe just above the horizon, and all around....exactly what you want for DX.

While I agree I'd not trade monoband yagis on land for vertical dipoles...for lots of reasons....that's not to say they're not very effective. Some well-financed DX-peditions with more bucks than god actually prefer the vertical dipoles, and claim as much as 18-20db gain. Obviously, the gain doesn't come from the dipole itself, but from the skipped hops, i.e., fewer hops to the receiving station because of the extremely low takeoff angle.

I've used and written about these for years. There's nothing that can even come close on a sailboat that's a true seagoing antenna, i.e., one which can stand up to the marine environment and to a rough seaway.

About 8 years ago I decided to try them on land at the home QTH where I have tall oak trees. I have vertical dipoles here on 20m, 30m, and 40m. Have worked over 100 countries QRP with no trouble at all...they work very well over land, too!

Why even consider them? BECAUSE THEY PUT OUT A WHALE OF A SIGNAL compared to a backstay antenna. This morning I listened to a pathetic exchange where a boat in Culebra was trying to contact a K4 here on the East Coast. No go on 40m. They decided to try 20m. Also extremely difficult copy. If the boat had been using a vertical dipole on 20m they would have had solid communication. How do I know? Because I've been sailing the Virgins since 1969, had my present boat there for 11 years, and know very well what a vertical dipole will do on this path compared to a backstay antenna.

Is it worth it? That's for each sailor to decide :-)

Bill

10-12-2007, 15:16	#83
btrayfors Senior Cruiser Join Date: Jul 2006 Location: Chesapeake Region Boat: 42' Bob Perry sloop, "Born Free" Posts: 1,241	Hey, Don... You've just been playing in the wrong sandbox all these years :-) Just kidding. I think we've both been foolin' with antennas for a very long time. What I was reacting to was your note about a horizontal dipole being best if rigged high enough. Clearly, that's not possible on a sailboat. More importantly, it just ain't so. The vertical dipole is such a killer DX antenna because, when rigged LOW to the ground, it's vertical radiation is very low. It has a huge lobe just above the horizon, and all around....exactly what you want for DX. While I agree I'd not trade monoband yagis on land for vertical dipoles...for lots of reasons....that's not to say they're not very effective. Some well-financed DX-peditions with more bucks than god actually prefer the vertical dipoles, and claim as much as 18-20db gain. Obviously, the gain doesn't come from the dipole itself, but from the skipped hops, i.e., fewer hops to the receiving station because of the extremely low takeoff angle. I've used and written about these for years. There's nothing that can even come close on a sailboat that's a true seagoing antenna, i.e., one which can stand up to the marine environment and to a rough seaway. About 8 years ago I decided to try them on land at the home QTH where I have tall oak trees. I have vertical dipoles here on 20m, 30m, and 40m. Have worked over 100 countries QRP with no trouble at all...they work very well over land, too! Why even consider them? BECAUSE THEY PUT OUT A WHALE OF A SIGNAL compared to a backstay antenna. This morning I listened to a pathetic exchange where a boat in Culebra was trying to contact a K4 here on the East Coast. No go on 40m. They decided to try 20m. Also extremely difficult copy. If the boat had been using a vertical dipole on 20m they would have had solid communication. How do I know? Because I've been sailing the Virgins since 1969, had my present boat there for 11 years, and know very well what a vertical dipole will do on this path compared to a backstay antenna. Is it worth it? That's for each sailor to decide :-) Bill