Kieth, A dipole cut for 40 meters will provide a high feedpoint impedance on 20 - and the L network used in the Elecraft tuners do not do high impedances very well.
Of course, all that does depend on your feedline length as well as the flattop length - the feedline will act as an impedance transformer when it has SWR on the feedline, so unless you can state the length and impedance and velocity factor of your feedline, we cannot answer your question with any degree of certainty. I use an antenna cut at 22 feet each side of center with a 25 foot feedline for portable use, and it works FB on all bands except that it is marginal on 30 meters - adding an additional 10 feet of feedline allows it to tune 30 meters just fine with the Elecraft L network tuners. I deploy my portable antenna as a horizontal dipole, or and inverted VEE, or as a vertical with a single radial, whichever is convenient for the location I have at the moment - I do carry a 32 foot collapsible mast to deploy the antenna if I have no other suitable supports. 73, Don W3FPR > -----Original Message----- > > Thanks for the quick response. For a field dipole I could use > that in an inverted V format I assume? I did purchase a > collapsable pole to try some of those out. If I used ladder line > or twinlead....would I need a balun in-line before connecting to > the T1? > > If I understood you correctly, I could cut the dipole for 40M and > then use the T1 to use it on other bands. For my base setup I > use a dipole setup and it works well on multiple bands....I am > just not real clear on how to make this work on a portable > setup with the T1 ATU. > > Is there any special twinlead or ladderline I should stock for > these projects? I hope to try a bunch of antenna designs for > different locations and learn from them...so I may as well stock > some wire. > > I think a recent QRP Quaterly that had a plan for a portable > vertical...I will check it out. > > Thanks again for all the advice. > > 73 de Keith KB3ILS > _______________________________________________ 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