balun on a dipole

[dime196604]

when making a simple wire dipole should i use a coax balun? can it make the antenna any better? and if so how would i go about making it? how big should the coil be? how big around should it be and how many turns should there be in the coil?

[Bombero]

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[231]

when making a simple wire dipole should i use a coax balun? can it make the antenna any better? and if so how would i go about making it? how big should the coil be? how big around should it be and how many turns should there be in the coil?

A coaxial choke is all that's needed on a 11m dipole. Half dozen turns about 6"-8" in diameter as close to the feed point as possible should do the trick. It doesn't make the antenna any better, it merely helps choke any stray RF from finding it's way back on the shielding of the coax, that's all.

Good luck.

['Doc]

If it makes you feel better, then use a 1:1 balun for an HF dipole. It isn't as necessary as some people think, and there are plenty of dipoles that don't have one. In something like 40 years of making dipoles, I think I've used one once. Didn't find any significant benefit to it so didn't use it again.
Baluns have ratings. Those ratings include usable frequency ranges, power handling abilities, and impedance transformation. The two biggies are the frequency ranges and the power handling abilities. Pick a balun where the intended frequency is in the middle of the balun's range. And that power handling ability is really flexible, and typically means use one rated for much higher power levels than you intend to use. All of those ratings are inter-related.
- 'Doc

[PoeDunk]

If you intend to run an amplifier, then most definitely use a balun at the feedpoint of the antenna. Higher power will cause rf to backup in the shack with any slight increase is swr. RF backing up into the shack can cause serious problems with the home electrical system, SAT TV receivers, PCs, and other stuff you don't even think about. I once saw a poorly designed antenna system take out one of those fancy new electronic control clothes washing machines. All from letting RF back up into the shack. Also be aware that dipoles are sensitive to trimming both ends equally to tune them.

I still run dipoles on multiple bands. Very dependable and cheap to replace if mother nature kills one in a wind storm or other mishap.

PoeDunk

[dime196604]

Ok thanks for all th input. i never have run any thing close to higher power so i think i will have no problem with out them.. I'm talking like ten watts max so i think i will ok with out.. the main thing i wanted to know is if it would help the antenna perform better.. So thank again for the input i will save me some time now

[SOL1776]

I have 2 opposing dipoles on my roof, just built and installed a balun on one of them, I'll let you know if I see any difference.