[Antennas] 600 Ohm Ladder Line

[Cletus W Whitaker]

de WB2CPN South Central Pennsylvania    2002.11.09

My experience with large and small transmitting rhombics, the 300'
to the 1100' feet size, (A, B, C, and Nested), the dissipation line
was 600 Ohm impedance.  The transmission line which fed the rhombic
was a 600 Ohm open wire line, and used a "tapered line" up to the
feed point on the rhombic which was 800 Ohms.  (Does anyone
know if that has anything to do with the impedance of free space?)
The tapered line down the pole at the far end connected to a 4-wire
"X" configured open line which was made of something like stainless
steel, and ran back up toward the feed point for a hundred yards or
so.  There's one Army TM and maybe more that covers rhombics very 
well.  That book has the math for figuring true headings from one
set of coordinates on the earth to another.  I'm talking pre-WWII.
A slide rule was a nice thing to have, otherwise a book with the
functions of angles was necessary.  Figuring just one took a while. 
                73  Clete