An EFHW is a very efficient antenna, but the usual tuner needs help. One way to use the EFHW is to put a toroidal winding at the base of the antenna, between the tuner and the antenna. Bifilar or trifilar or quadrifilar windings configured as a tapped winding will reduce the tough impedance to something that the tuner will handle easily.
The 80 meter version of this, an end-fed half-wave L fed against ground is probably the best single wire antenna for 80 meters that there is. 73, Guy. On Tue, Aug 23, 2011 at 11:50 PM, Phillip Shepard <ph...@riousa.com> wrote: > Thanks for all of the great advice. This reflector is a fountain of > knowledge! I checked the 33' antenna/16' counterpoise combination with an > MFJ259B, and it indicated over 25:1 SWR. Extending the antenna to 39' and > adding a second "radial" of 6' gave an SWR reading of about 11:1 with the > antenna analyzer. The KAT2 seems to handle that much better. This will > get > me through one or two SOTA peaks at Crater Lake later this week; and I can > look for better solutions after that. Thanks again. > > 73, > > Phil, NS7P > > -----Original Message----- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net]On Behalf Of Phillip Shepard > Sent: Tuesday, August 23, 2011 4:00 PM > To: elecraft@mailman.qth.net > Subject: [Elecraft] KAT2 with EFHW antenna > > > I have been using my K2 with an MFJ tuner to feed an end fed halfwave wire > for portable use (like SOTA). The 20m antenna is 33' long and I use one or > two 16' counterpoise wires. It seems to work well for what it is and 10W. > I just built and installed the KAT2 ATU into the K2 to lighten my pack by > the loss of the MFJ. The KAT2 tuner checked out fine on the bench, but it > had a very hard time getting a good match to the antenna. In AUTO mode, it > only got the SWR down to about 5:1. I put it in ALT mode, and it spent a > long time searching before it got down to between 3:1 and 4:1, depending on > the 20m frequency. I added about 2" of wire to the antenna, and the tuer > got down to about 2:1 to 2.5:1. I added another foot of wire (now 36'), > and > it got down to about 1.5:1. Five or six feet added yielded a perfect match > (1:1). So I now have a 39' wire for 20m use. > > Is this normal? Should the KAT2 be able to more easily match the 33' > halfwave antenna? Thank you. > > 73, > Phl, NS7P > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
