Thursday, 15 March 2018

Silent Too Long

Well I went the whole winter without even turning a radio on and I was worried that I had lost my interest.  A lot has been going on which has had my mind on other things but all it took was listening to a couple of episodes of one of my favourite podcasts the QSO Today Podcast to get my mojo back.  I can always count on Eric (4Z1UG) to kindle my interests...especially on the QRP front.  I also believe some of my issue was the havoc the wind has been playing on my inverted vee antennas (not to mention the grim propagation these days).  The tangling that occurs with the fan dipole style of antenna is disappointing.  I need a better solution and I believe I may have found it.  I read an article in the ARRL Wire Antenna book that I bought from Amazon last fall.  The antenna from the article I read has the radiating elements made from ladder line/window line.  I can have a 2-band dipole that will not get tangled because the wires are evenly spaced/separated by the windows.

What is done is the length of the longest leg (34' for 40M) and the length of the shortest leg (24' for 30M) are added together making a 58' piece of ladder line the requirement for a 40/30 fan dipole.  Then you lay the cable out and measure 34' from one end and cut the top conductor.  Measure 34' from the opposite end and cut the bottom conductor.  What you have now, if you cut along the red line as shown below, is 2 pieces that will act as each leg of the dipole.  The long top wire is one side and the long bottom wire flipped over and end for end is the other side.

Then you need to strip the conductors bare at the double wired end and solder them together and attach them to the coax to create the feed point.  One leg connects to the center conductor and the other side to the braid of the coax.

Once this is completed you will have to raise the antenna and tune it for your desired operating frequency as with any dipole antenna.  I plan to build two of these.  One for 40/20 and one for 30/17 and I will post the results including photos of the tuning and testing process.

Cheers and thanks,
Scott, ve3vvf/qrp

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