I have searched in a number of places and I am seeing answers that contradict each other. What I am looking for is a simple formula to calculate the optimum length of 300 ohm ladder line to a dipole. I have seen some sites saying the feed-line should be a 1/2 wavelength of your dipole (not sure how to calculate that if the dipole is used for multiple bands) then I read a website that said that the feed-line length must never be equal to 1/2 wavelength of the frequency the dipole is cut for.

So, with that said, can anyone please provide me with a formula so I can redo the feed-line length's to my two dipoles and get the optimal length so it is an easy match for my tuner and I do not have huge losses in the cable.

At this point my ladder line terminates into two baluns outside of my house then there is a 50' or so run of coax to my radio. I am thinking of running the ladder-line through the sill of my basement window and run the ladder line through the basement, through a hole in the floor and then place the balun within a foot or two from my rig.

Also, if someone can provide me with a formula to calculate loss in the feed-line that can be used for both ladder line and coax. It's OK, if the formulas are a bit complex as long as all the variables to enter into the formula are clearly defined.

This would be a huge help to me.

P.S. If I'm only putting out 100 watts and I do end up running the ladder line along the rafters in the roof of my antenna, will I have any issues of RF interference inside of the house? This has always been my main concern and is the reason I always left he baluns outside and ran coax into the house to the rig.

Thanks,

Adam