On Sun, 14 Feb 2010 16:17:50 -0800 (PST), djmd <[email protected]> wrote:
See comments in line... >I live in a very standard subdivision-type lot, about 180'x70' with a >single-story 55'x25' house right in the middle. The one option that I have >to rule out is putting the antenna smack-dab in the center of the backyard. >Besides just not wanting an antenna in the middle of my backyard, that would >put the antenna way too close to the 7200v powerline strung over my property >line. About the only ground-mounted option would be 5-10' away away from the >back of the house, which would make it clear the high-power line, but it >could still come in contact with my 240v residental feed if it went over in >that direction. As Julius say's, don't fall for the 43 foot vertical hype. It would be better to get a short loaded 5 or 8 band vertical and install a ground system for it (more about that below). Most of the loaded verticals on the market are short enough to be clear of both of your power lines if they fell. Loaded verticals do not require a tuner if you adjust them for your favorite part of each of the bands, so you would save the money you would have to spend on a tuner. >My ideal location would be on the roof. Not only could I be 100% clear of >any powerlines, phone, or cable, but it would be nearly 20' higher, and >basically in the clear of anything to the sides. My question, therefore, is >what about radials? Draping radials across the roof doesn't sound like an >option to me, mainly for asthetic reasons. So I ask: could I send #2 or #4 >copper from the antenna base to both the front and the backyard, and connect >it each one to radials in both the front and back yard? I would be mounting >this antenna within 10' of the end of the house, so I could send 1 piece of >copper down one of the ends of the house, and then split off from there in >each direction. It would probably then take about another 20-30' in each >direction before it met with the radial distribution point. I agree that your ideal location would be on the roof, but you don. need to have the radials at ground level. As others have said that would actually harm the performance of the vertical. You could mount the vertical on a short mast three feet in length, then use good stronger copper wire or galvanized steel electric fence wire for the radials, attaching them to the roof, making sure you use insulators on the ends of the radials, which are also your guy wires for the mast. Then use 3/6 inch UV resistant rope to guy the antenna itself at three or four points on the roof. You can use the same attachment points you used for the radials. Another method of installing the vertical is to mount it on an eight foot pipe or wooden 4 x 4 post using the radials to guy the post or pipe (I prefer the post). It is best that the radials are parallel to the ground. Either installation will result in the installation of a ground plane antenna. Do a search on the Internet for "ground plane antenna" and see if anything you find resemble a solution for your antenna needs. Also consider a single mast with inverted vee's all fed at the same feed point, which in most instances will out perform a loaded vertical antenna and cost about 20 dollars to build. Building antennas is much less expensive than buying them ;o) [snip] >K8DJW Tom, N5GE [email protected] K3 #806 with SUB RX, K3 #1055, PR6, XV144, XV432, KRC2, W1, 2 W2's and other small kits 1 K144XV on order http://www.n5ge.com http://www.swotrc.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
