This antenna has become quite popular, as the performance is exceptional.  It's a dipole, fed 14% off center with a 4:1 balun.  It will work 80-10 with the built in tuners found in most radios today.  External tuners work quite well also.

  The formula:

  for a dipole antenna cut to 3.6 MHz, take 468 / 3.5MHz and you get 130'.  That is the overall length of a standard dipole.  Normally you divide that in half to find the center feed point; however, we are feeding this 14% off-center to add 14% to 50% and you get 64% for the longest leg and 36% for the shortest leg.

  So, 130' multiplied by .64 (64%) gives the longest leg length of 83.2 feet.  the shortest leg length is the remainder, or 46.8 feet.  You can double check this by reversing the math, 130' multiplied by .36 (36%) for the shortest leg is still 46.8'.

  You can calculate in the velocity factor for 12 or 14 AWG stranded copper, jacketed wire.  Simply take the lengths and multiply them by .975 and you will get the RF lengths of your wire.  With these antennas, and the fact that we are using tuners, I have never found shortening the physical length by the velocity factor to give the RF length, any real performance significance.

  So, all you hams out there wanting to build this working version of the Off-Center Fed Dipole, get a 4:1 current balun, feed that with the lowest loss cable you can find, go to Home Depot and buy yourself 132' of 14AWG stranded copper wire.  I like to get the white colored stuff, it disappears against the sky better.  Buy yourself a small length of 1" PVC pipe, cut two 6" lengths for your end insulators and get some rope to tie the thing up with.

  Cut your 132' of wire to 84' 2 1/2" and strip back about 6" off of one end, make your balun connection and solder it.  The remaining piece of wire, same deal, strip back 6" make the balun connection.  Measure from the balun eyelet out to 83' 2 1/2" and mark that point. That is where the wire passes through the PVC insulator you made for the end.  Similarly, for the opposite end, measure from the Balun eyelet out to 46' 9 1/2" and mark, that is where the end passes through the other insulator you made.