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## [TowerTalk] Half slopers using a tower

 To: [TowerTalk] Half slopers using a tower W8JI@contesting.com (Tom Rauch) Tue, 1 Jan 2002 17:37:58 -0500
 ```> Please explain what "5 or more above" implies.....There have been many > others that have shared some very good results with the HALF SLOPER > antenna. Sounds to me like this antenna is anything but a "free lunch" > antenna. Taking the time to understand the functionality of an antenna > is well worth its weight in gold to me, even if it means a little > extra experimentation initially. Modelling is great for that. You can look at where the current is, or you can visualize it. Keep in mind there is EXACTLY the same current in the shield and the center conductor, unless the feedline is radiating like an antenna! What do you think happens with all that sloper current exciting the tower?? A simple dipole 1/2 wl high is about as good as we can get for minimum work. Unfortunately on 160 the height is a problem, and a good vertical generally works better anyway. With an antenna close to earth (much less than 1/2 wl) and especially with vertically polarized antennas, we are kidding ourselves if we think we have an efficient system without have a good amount of radials below the antenna. The "free lunch" syndrome is where high efficiency and top-notch performance is promised with a "next-to-no-work" system, or in some cases a small system. The most profound examples are some of the magical compact beams and E-H or CFA antennas that claim to defy all the rules. I see I left the dB off after 5. You can expect a vertical with a good ground system to be 5 or more dB better than a system where you try to get away without a ground, or get away with a small ground system. Now I admit when you are 20 over nine and on a clear frequency, no one will notice the difference for all the extra work. But when you are in a pile-up, or when conditions are poor, even 1dB can be significant. 5 db is amazing, many or most S meters (low on the scale) are only about 1 or 2 dB per "S" unit. It is true they are often reasonably close to expected up around S-9 or higher. But consider what a couple dB sounds like on a marginal signal! If you want to work general ragchews, you can get by with almost anything. If you want to work people when signals are weak or the noise is high, the work is worth it. My 160 vertical is sometimes 20dB better than my dipole at 300 feet, and almost never weaker than that very high dipole. A dipole at 85 feet is always several dB below the high dipole. When conditions are good I can use any antenna, but when they are poor the work on the verticals really pays off. 73, Tom W8JI W8JI@contesting.com This list is sponsored by the new eHam.net Store. When you buy products like ICE filters, Array Solutions StackMatch, or M-Squared Antennas from the eHam Store for the same price you pay direct, a portion of the sale price goes to support this list. Check it out at http://www.eham.net. ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
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