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vk3pa
Deceased
Australia
1714 Posts |
 Posted - 13 Dec 2006 : 08:08:35 AM
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Hi,
Since you have 80 feet or so, here's a thought...
Get you about 70' of wire (stranded, copper-clad steel is good), a 4:1 balun (a few bucks), three insulators (one for each end, and one for the center), and some Dacron rope (won't stretch too bad).
Take the number 468, and divide it by the mid-point frequency of the lowest band on which you will operate, in this case, 40m (you don't have enough horizontal space for 80m). This calculation will give you the total length of wire you will need, including the twist-ties at each insulator (should calculate to about 66-67 feet).
Now, split this length into two sections using the ratio 64/36, cut the wire at this point, and insert the center insulator along with the balun coil connectors. You should have about 42 feet of wire on one side of center, and about 24 feet on the other side.
Feed this guy with RG-8 (RG-8x), directly into the connector on the balun, and erect the center feedpoint as high as you can. The ends may droop some, but that's O.K. Just keep the end insulators as far above ground as possible, and the wire clear of trees, etc.
You now have what is called a Windom, and it will work very well on 40, 20, 15, and 10m. 15m will have the highest SWR, but it won't be that bad (maybe 2.5:1). SWR on the other bands should be around 1.5 or less to 1.
Trust me, this is a simple, good, multi-band antenna. I have worked over 50 countries in the past two months with one here in Atlanta, and have no problem being heard (100 watts SSB) if I can hear the other station. It might take a couple of hours to build and erect.
Send me an e-mail at w5sdj@att.net if you have any questions. Or I'd be glad to talk you through the construction if you like.
Jim
W5SDJ
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Another simple ant 40m>10m
