I've used an end fed dipole (i.e. half wave wire) a lot. I'm currently using an end fed 80 meter dipole in my fixed-station setup. Such an antenna presents quite a high impedance at the end, of course. That impedance is outside the range of the KX1, and probably the K2, although I haven't tried it on the KAT2 tuner for the K2. However, you don't have to be very far off of exactly 1/2 wavelength for the tuner to find a match.
Normally, I use a link-coupled tuner when feeding such antennas. As you probably know, the closer you can get the antenna to exactly 1/2 wavelength at the operating frequency, the lower the ground return losses. Indeed, at 1/2 wavelength long it doesn't really need a ground except that without an RF ground the rig will tend to "float" up to the high impedance so you will have "rf on the rig". For that reason, it's a very good idea to plan on some sort of ground: 1/4 wave counterpoise, etc. The antenna is efficient without it, but the ground will help hold down the RF voltage on the rig. The KX1 tuner has the most limited range of all the Elecraft tuners to date. That's because of the very small space available for coil/capacitor combinations on the tiny board inside the KX1 case. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave Andrus Sent: Wednesday, February 20, 2008 10:36 PM To: [email protected] Subject: [Elecraft] K1, KX1, K2 antenna tuner high-impedance feed capabilites I'm interested in using portable end-fed halfwave antennas when I'm out camping. I have a Norcal BLT tuner that is a absorptive Z-match type, suitable for this type of high-impedance tuning and loading. I'm finishing my build of a K2 right now, just about to add an internal tuner to it, and I also plan to build a KX1 in the near future (and who knows, maybe a K1 as well?). I'm wondering whether I should add the tuner in, or just carry my BLT around with me? Since many of you are QRP buffs, and have possibly had occasion to use this type of antenna (and maybe even the BLT) in portable locations, could you tell me if the internal tuners in these rigs are capable of feeding this type of antenna successfully? I don't just mean to ask whether an L-match or T-match type of tuner will handle a high impedance load, but also whether the best power transfer is happening, such as what the BLT will do? Thanks in advance, Dave K7DAA http://www.k7daa.com _______________________________________________ Elecraft mailing list Post to: [email protected] 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: [email protected] 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
