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On Sun, 22 Apr 2012 23:18:17 -0600, "Irv Finkleman"
wrote: I just want something quick and cheap so I've ruled out anything like copper clad steel and such. Will your 25ft span of copper wire support a few birds? If not, please reconsider copperweld. Just to clear things up on the geometry, the wire will run out the window horizontally to the tree (about 25 ft) and then drop vertically (another 25 ft approx) through the tree to just above the ground. Sort of an inverted letter "L". It is just a random wire, and the best I can do at the moment given my current situation. Do you have an antenna tuner? The FT-817ND does not have a built in antenna tuner. You're going to need one with your random wire and random configuration. The hole through the window frame is too small (1/4 in.) for conduit but I plan to use a heavy plastic kids drinking straw, tilted down on the outside, and plugged with some silicon seal at each end where the wire enters and exits. Ummm... is this an existing hole are you going to drill a new hole? The modern windows that I've seen have the glass extend almost to the edge of the frame with only a sheet rubber spacer in between. You're highly likely to drill through the glass if you decide to drill the frame. I may even try loading the window frame (aluminum, 5 ft x 5 ft (approx)) using a handy sheet metal screw for the connection. With 5 watts, that might work. Forget about building a magnetically coupled loop. You would need to split the frame at some point, and install a variable capacitor. That's probably not going to happen. If your window proves to be uncoated glass (unlikely), you might consider two squares of aluminum foil on both sides of the window to couple through the RF via a ladder line. You won't get much capacitance so it won't work on the lower frequencies, but should be tolerable for the higher bands. A reminder -- the ground system will be tuned counterpoise wires running along the wall inside my apartment. I have an MFJ-1623 tuner which will handle tuning the antenna and the counterpoise in a very nice compact arrangement with only one meter to watch! Good, you have a tuner. However, that's designed specifically to handle a 12ft balcony mount HF antenna. I don't know what it will do with a longer antenna. Looking at the schematic: http://www.mfjenterprises.com/pdffiles/MFJ-1623.pdf it seems to be a crude L match, which isn't going to match every combination of reactance and frequency. The meter does NOT indicate VSWR, so you really won't know if the tuner is effective. My guess(tm) is you're going to purchasing a more elaborate antenna tuner, a VSWR meter, or using a 12ft piece of wire. I once used a large sheet of WELDED chicken wire under the carpet for a "ground". It has to be welded to prevent the galvanizing from forming diodes. It sorta worked but nobody wanted the lumpy carpet. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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