Shaun, it will decrease the efficiency drastically. A two meter long 80 meter dipole will be about 10% as efficient as one 40 meters long at the same height. Most texts quote dbi information for a full sized dipole 100 feet high. If you put your antenna near the ground it may not be much more than 1% as efficient as the full sized antenna at 100 feet. You can't cheat the laws of physics, they work the same even if no body is watching. There is no substitute for high and big!
If you are trying to run QRP with 5 or 10 watts then you will be doing well to work across the street. In addition, the antenna you are considering will have an impedance of only an ohm or two and be almost impossible to match. Sorry, nice idea, but it will not work well at all. Cookie, K5EWJ, BS Physics, PE/EE, 52 years a ham --- Shaun Oliver <[EMAIL PROTECTED]> wrote: > Hi all, > if I were to make a dipole, would coiling it round a > piece of plastic > piping decrease the efficiency of the thing? I > intend on making one for > 40 meters, one for 80 meters, and one for 10 meters. > I've worked out > that1 meter of piping will suffice for each leg of > each antenna. > thanks in advance. > shaun > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
