Sunday, November 18, 2012

40m V Dipole - It's up and awesome!

Well, it sure has taken me a while, but I decided that I needed to remove my doublet.  I was doing some antenna modeling with EZNec and CocoaNec and saw just how horrible the actual antenna resonance was and realized that even though I could get my tuner to match; the doublet was still not exactly working very efficiently :(

So, those thoughts as well as the desire to run a little bit of power in the future and CW, caused me to re-think my antenna situation.  After much fun, deliberation, and consternation, I decided that I'd bite the bullet and build 1 - 40m dipole and 2 - 20m dipoles.  I went to Balun Designs and picked up a couple of baluns:  the 1116de (for 40m) and the 1115e (for 20m).  Wireman got the call for some more #531 wire and I was in business.

I'd be doing quite a bit of antenna modeling and decided that I did not want a flat-top dipole, I wanted a V that I could "control" the angles a little bit.  So, I came up with something of a compromise - I tied a 50' piece of rope between the insulators, hung the wire from the insulators, and the antenna balun hung down in the air between the wires.  It sounds more complicated than it really is - the rope just let me accurately define the length of the legs of the dipole.  It also meant that I could get the Impedance down to around 48 - 52 ohms or so :)

This afternoon I got to go outside and work on my latest adventure.  I think I dropped and raised the balun and wires about 7 or 8 times, but at the end, it was certainly worth it!  I was trying to get my lowest SWR around the 7.150 mark and was only just a little bit off.  I guess I could have kept cutting, but after a while you're just in the right ball park and it's time to call it a day :)

I wired it up, connected to some LMR 400 and listened around for a little while.  Perhaps conditions were just excellent today, but I had MANY, MANY stations around that were S9+40.  I listened to a contest running and gave a shout out, immediate response with a "Hey, your 60+ over here in Annapolis" - I replied with a "Thanks for the station report, new dipole and I'm very pleased!"  I'm also very pleased that my rig was pulling more amps than I'd ever seen - FINALLY, an antenna that is NOT a compromise - just works!

73 de KJ4WLH

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