Home |
Search |
Today's Posts |
#9
|
|||
|
|||
Open Wire fed lengths
"Ron Walters" wrote in message t.net... After reading several articles both on and off the WEB regarding a center fed antenna, only one article mentioned a recommended length for the feed line. some antennas, like the g5rv rely on a particular length of feedline because it becomes part of the antenna and radiates on certain bands. others use it as an impedance transformer. One article recommended odd multiples of a wave length is desirable at the lowest operating frequency while other articles don't address this. that is a myth that has been around for many years. there is no 'magic length' that works better than others, except maybe the shortest length that reaches from the antenna to the transmitter. The only reasons to use longer lengths is if you need to use it as an impedance transformer because the antenna isn't matched to the line, or to allow for future rearrangement of the shack. what can be handy about the 1/2 wavelength line is if the antenna isn't matched to the line impedance the antenna impedance will be repeated every 1/2 wavelength along the line. so if you have a 300 ohm antenna and a 50 ohm coax, every 1/2 wavelength along the line you will see the 300 ohms again. this of course only works on harmonically related bands. |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Zo of two wire open line | Antenna | |||
OPEN WIRE LINE | Antenna | |||
Adding lengths to bare wire antenna? | Antenna | |||
WTB: 2" open wire spreaders | Equipment | |||
WTB: 2" open wire spreaders | Swap |