Running dual 600 ladder line

[n9uib]

Hey everyone,

I have a question that i can find online. I am running a home brew 80 meter dipole with home brew 600 ohm ladder line into the back of my tuner.
It works great until i get about 10 meters and then it gets flaky.

What i want to do is make another dipole 20-10 meters and also feed it with home brew 600 ohm ladder line. Here is the question, Can i feed both dipoles at the same time with the same tuner ???? Or, will this give me a funky radiation pattern ?????
Sorry, if this sounds like a newb question, but i am curious

Steve

 

[WA8ZYT]

Why are you feeding an 80 meter dipole antenna, which has a native impedance of 72 ohms with 600 ohm feed line?

Are you attempting to make a fan dipole? You might be better off using a coaxial feed line.

 

[n9uib]

i am using it as a multiband antenna.......that's the reason...


steve

 

[W5LZ]

An easier way would be just to change the length of that feed line, that's probably where the 'funkiness' comes from. Or, just add that 10 meter dipole to the mix. Will it result in an odd radiation pattern? Sure, but no worse than if you used that 80 meter length. Who knows, it may 'put' one of those 'lobes' where it might do some good?
- 'Doc

 

[n9uib]

Thanks for the answer Doc...... might just give it a try....!!!


Steve op:

 

[gt40425hp]

i had the same thing going on and when i messed with the feed line i would lose another band .. so i looked at what realastate i had to work with and found i could put up a deltaloop for 20 on up and that antenna works great

 

[Captain Kilowatt]

Why are you feeding an 80 meter dipole antenna, which has a native impedance of 72 ohms with 600 ohm feed line?

Are you attempting to make a fan dipole? You might be better off using a coaxial feed line.

You don't want to use coax to feed a dipole if it is to be used on multiple bands. It will present 75 ohms only when operated on it's fundamental frequency. When operated on it's harmonics the impedance is anything but 75 ohms and often is many hundreds of ohms or even higher. For single band operation coax is fine. Right now I am using an 80m doublet with 450 ohm ladder line and a remote mounted Yaesu FC-40 tuner and homebrew 1:1 current balun right off the tuner then ladder line to the antenna. Coax runs about 45 feet from the radio to the tuner.