Ladder Line and Twin Feed Line

[HomerBB]

I have noticed that in discussions about Amateur antennas there is a lot of discussion about twin feed and ladder line instead of coax as a preferred antenna feed line, esp with wire antennas. I have used skywire loops, dipoles, inverted v's and horizontal with CB, yet have never seen any discussion on the merits of these feed lines for CB frequencies.

Why would one not want to use ladder line one a base setup for CB? Or why would I want to use it?

Sorry to show my ignorance. . .

 

[SR385]

Open wire line/window line/ladder line/balanced feeder

Advantages are, far lower losses in the line, particularly at high SWR condition.

Great for very long runs...hundreds of feet to a distant antenna.

Great for wide band tuning an antenna on multiple bands with a manual tuner. Example, a dipole at least a 1/2w length on the lowest frequency, will pretty easily tune any higher band using a wide range manual tuner. With balanced feeder, you have very low losses even when SWR can easily be over 30:1.

Coax, you don't have to worry about how you feed it, it doesn't care if it runs next to metal objects. It's compact so it fits through sealed pass-through holes easily. It's somewhat more commonly available to buy.

Coax is meant to feed a resonant antenna. If you push the tuning too far off the design and the SWR goes up, you will lose a bunch of signal to heat in the coax.

For a CB antenna, just feed it with coax, they are resonant and for a single band, tuning one from end to end won't give you enough loss to care about.

For an HF antenna, cut a 135' dipole, feed it with open feeder and a good wide range manual tuner and work from 80m up through 10m on the same wire.

 

[HomerBB]

Thanks for the reply. Very clear and helpful.