Dave (and Don), Not a silly question, Dave, what so ever.
My suggestion was to open it up 90 degrees from the present feed-point, 1/4 way around...this being a voltage maximum (loop) and current minimum (node). This enables the loop to still act like a loop on 80, if you desire to maintain it's present performance. And then on 160 it acts like, as Don states, "a folded back 1/2 wave dipole on 160 meters" but in this case it will be off center fed. Auto 80/160 band switching, once you get the lengths correct for the two bands, if that is possible in this case, as I do not know what modes you operate. If you open it at, as Don suggests, 180 degrees or half way round, the 80 meter loop turns into a bent 80 meter "2 Half-waves in Phase" with a very high Z feed, if you maintain the feed point as is. This also shifts the standing wave current distribution by 90 degrees, which might cause you problems if your original antenna was set up to favor a particular area of the world. Not convinced that is the case though, as it does sound like you have up 270 feet of wire in a triangular loop, "cause that's where the trees be". Wish I had those trees -- hi. 60 feet above ground is low for a horizontal 160 meter sky hook, but you do what'cha gotta do. Sounds like a fun modeling and empirical experiment to say the least. Regards -- Rick -- W5RH ------------------------------------------------- Dave, Open it at the point 180 degrees (midway around) from the feedpoint. If your existing loop is a full wavelength on 80 meters, opening it will turn the loop into a folded back 1/2 wave dipole on 160 meters - not as good as straight out, but it should work since you are feeding the line with a tuner anyway. In fact, you may be able to make it automatic by using a trap tuned to 160 meters - that will electrically open the loop on 160 and only add some inductnce on the other bands. 73, Don W3FPR > -----Original Message----- > > Not sure where you are suggesting I open it. I was considering > disconnecting the feedline on one side where it connected to the balun. > Is this what you mean. My apologies if it is a silly question. > > David Wilburn > [EMAIL PROTECTED] > > > > Rick Hiller wrote: > > Dave, > > > > Another possibility for 160 -- Don't know to what extent/effort > you want to > > go to get on 160, but here is an easy way, although, a bit of a > compromise. > > > > Simply open the loop at one of the 80 meter voltage loops (also > a current > > node). The 80 meter standing wave current distribution > /performance will > > not change, but it will force the wire to be an off center fed 1/2 > > wavelength for 160. Although not quite resonant within the 160 > meter band, > > if you feed it with open wire and run it thru the appropriate matching > > network, you should be right. -------------------------------------------------------------- Rick Hiller Toll Free: (866) 658-7527 Manager, CAD Sales Direct:: (713) 278-6310 SDI -- System Development, Inc. Main: (713) 266-5667 11111 Richmond Ave., Suite 110 Fax: (713) 974-4911 Houston, Texas 77082 [EMAIL PROTECTED] 2D Graphics Tools to View, Edit, Convert, Publish and Print If you deal with CGM, visit www.sdicgm.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