The following lines were added (+) and removed (-):
* Where to place the balun - place it* Where to place the balun - depends on factors however the antenna tuner has a balun internally.* Twisting - Windowed line should be twisted about one twist for every two feet to prevent wind-induced oscillations.===Doublet Antenna -w- ladder line===[[Image:hamradiodoubletdiagram01.png]]An antenna tuner with a built in balun matches the feed-line impedance to the 50Ω coax of the transceiver. The length of the antenna is for the lowest frequency that it will be used on at ½ wavelength. It wills serve for higher frequencies above the lowest match. Never install a balun between the ladder line and the antenna at the feedpoint since they already have the correct match. Estimations:*160m (1.8 Mhz) overall length - 254' from insulator to insulator.*80m (3.5 Mhz) overall length - 134' from insulator to insulator.*40m (7.0 Mhz) overall length - 67' from insulator to insulator.Length here is from end to end, including both ends of the dipole. Simply divide by 2 to determine the wire length for each pole.Basic Formula:*Feet length = Total length - 468 / frequency L = 468/f.To calculate the length of each individual pole, = 234/frequencyTo calculate the total length from end to end (both poles) = 468/frequency<small>''When creating an HF antenna they say (they being experienced hams) that you should add about 2' extra to compensate for the inaccuracy of the magic number "468." According to the ARRL Antenna Book, the "end effect" due to the attachment of insulators at the ends of the antenna results in the approximately 5% reduction in length from the free-space 492/f to 468/f. The percentage varies slightly with different installation. Height of the antenna above the ground has a significant impact.''</small>Connection:The all band doublet antenna is a 1/2 wave dipole cut for your lowest operating frequency. It should never be connected to the tuner with coaxial cable. The best choice is 450Ω ladder line from the antenna wires to the antenna tuner. You will end up with an antenna that can be used from the lowest cut frequency up to 10-meter on your HF ham transceiver.People have used 300Ω flat television line, however, due to the gauge of the wire this should never be used to transmit with more than 150 watts of power. The impedance issue doesn't seem to be significant according to many sources, as 300 ohm wire can work as a substitution for 450 ohm ladder line. The impedance is the result of the spacing of the twin wires. The 300 ohm television wire simple has the twin closer together. What is extremely significant is that the spacing of the twin wires is consistent.One Wire, One Antenna:Some hams take the 450Ω ladder line and tear one end down the middle separating the two wires for the distance equal to the length of each pole in the HF dipole. This gives them one antenna made from the same wire as the feed line. Where the separation ends is the feed point and from that point to the window the wire remains in the evenly spaced pair. ==External==[http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1993/12/page70/ The lure of the ladder line] by Rob Kalmeijer (WB8IMY)[[Category:HAM Radio]][[Category:Ham Radio]]