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Half wavelengths accounting for common coax velocity factors for 27.185 MHz...

.66 velocity factor is a hair under 12 feet
.85 velocity factor is about 15 feet 3 inches

These lines account for the lower and upper ends of the coax velocity factor scale... If you use some 450 ohm windowline (not the old 300 ohm tv twinlead stuff) you can get in the range of 17 feet 2 inches, however, that type of feedline, while useful in its own right, is rarely if ever used for CB operation, especially by those that perpetuate the 18 foot myth... If your a real stickler you can custom make some open wire feedline that has even higher velocity factors, in the range of .97 and higher.

However all of this information is useless to you unless you are either phasing antennas, using a quarter wavelength feedline transformer of another impedance, or you have a tool more advanced than an SWR meter...

If you want to confuse those who perpetuate this myth even more mention to them that the 1/2 wavelength of the standing wave on the coax is 1/4 electrical wavelengths long, just to get their reaction...

The DB

Edited for accuracy.

<blockquote data-quote="The DB" data-source="post: 455165" data-attributes="member: 21346">Half wavelengths accounting for common coax velocity factors for 27.185 MHz....66 velocity factor is a hair under 12 feet.85 velocity factor is about 15 feet 3 inchesThese lines account for the lower and upper ends of the coax velocity factor scale...&nbsp; If you use some 450 ohm windowline (not the old 300 ohm tv twinlead stuff) you can get in the range of 17 feet 2 inches, however, that type of feedline, while useful in its own right, is rarely if ever used for CB operation, especially by those that perpetuate the 18 foot myth...&nbsp; If your a real stickler you can custom make some open wire feedline that has even higher velocity factors, in the range of .97 and higher.However all of this information is useless to you unless you are either phasing antennas, using a quarter wavelength feedline transformer of another impedance, or you have a tool more advanced than an SWR meter...If you want to confuse those who perpetuate this myth even more mention to them that the 1/2 wavelength of the standing wave on the coax is 1/4 electrical wavelengths long, just to get their reaction...<a href="http://hittman.us" target="_blank">The DB</a>Edited for accuracy.</blockquote>

[QUOTE="The DB, post: 455165, member: 21346"] Half wavelengths accounting for common coax velocity factors for 27.185 MHz... .66 velocity factor is a hair under 12 feet .85 velocity factor is about 15 feet 3 inches These lines account for the lower and upper ends of the coax velocity factor scale... If you use some 450 ohm windowline (not the old 300 ohm tv twinlead stuff) you can get in the range of 17 feet 2 inches, however, that type of feedline, while useful in its own right, is rarely if ever used for CB operation, especially by those that perpetuate the 18 foot myth... If your a real stickler you can custom make some open wire feedline that has even higher velocity factors, in the range of .97 and higher. However all of this information is useless to you unless you are either phasing antennas, using a quarter wavelength feedline transformer of another impedance, or you have a tool more advanced than an SWR meter... If you want to confuse those who perpetuate this myth even more mention to them that the 1/2 wavelength of the standing wave on the coax is 1/4 electrical wavelengths long, just to get their reaction... [URL="http://hittman.us"][COLOR="Black"]The DB[/COLOR][/URL] Edited for accuracy. [/QUOTE]

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