I enjoy putting together and playing with simple wire antennas for field operations. I have also been fortunate to enjoy moderate success with my efforts.
However I am looking to refine my approach in an effort to make my systems more efficient. My approach in the past has been to follow designs and dimensions for established dipole’s and doublets, then check my effort by using an MFJ-259 to verify that they fall within acceptable limits for my tuner and desired frequency range. I am not looking to build an antenna that will give me 1:1.0 SWR but rather try to change the feed-line impedance to produce a better load transfer. Currently I am using a 135’ doublet with 50’ of 450 ohm ladder line, but I am looking at trying an 88’ Doublet and different types of balanced transmission lines to vary the input impedance, by using 300 ohm, 450 ohm ladder line or even trying some home built 650 ohm ladder line. I have read several articles and books on antenna building but have missed anything that addresses this aspect of antenna construction. That is not to say that it hasn’t been discussed only that I have not seen it. The following links and articles have been very helpful: L.B. Cebrik’s W4RNL’s technical articles “10 Frequency Asked Questions about the All-Band Doublet” http://www.cebik.com/wire/abd.html “My Top Five Backyard Multi-band Wire HF Antennas” http://www.cebik.com/fdim/fdim9.pdf “Some (Old) Notes on Home-Brew Parallel Transmission Lines” http://www.cebik.com/trans/par.html “The Minimalist Backpack Antenna System” by Bonnie Crystal KQ6XA http://www.qsl.net/kq6xa/antenna/ I have downloaded and tried the trial version of EZ NEC only to be totally confuses with my effort. I would appreciate some feedback on my thought process, am I running down a rabbit trail that has already been explored as a wasted effort? Is there someone on the reflector that understands owns and understands EZ NEC that could provide me feedback on what the modeling results would be with a 135’ doublet or 88’ doublet with 300 ohm, or 450 ohm or 650 ohm ladder line on 80M, 40M, 30M and 20M at a height of 45’ to 65’. Of course if I am all wet then please be kind enough to respond off the reflector and spare me the embarrassment of appearing to be a complete moron. 73 K2CG Chuck G. _______________________________________________ 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
