Toroid or bead ferrite which to use?

[Jim5570091]

Which works better at preventing common mode currents on outside of coax? Ferrite beads or wound toroid?

 

[Crawdad]

My understanding is that multiple turns through a toroid will present more choking impedance than a single coax with multiple beads, all things being equal.

 

[Greg T]

I've always had excellent results using a small length of 4" sched 40 plastic sewer line with 6 wraps of coax held in place by zipties. Worked perfect every time for me.

 

[fourstringburn]

Which works better at preventing common mode currents on outside of coax? Ferrite beads or wound toroid?

Toroid,

Be sure to by the correct Mix value for the toroid ring. Mix 31 is good for all HF frequencies from 1-300 Mhz while Mix 43 is rated at 25-300 Mhz. Either one for CB band only.

If you want the a ready made choke balun this one here is what I use. The Dual core choke balun offering the maximum choking impedance. These are offered in many connection types from SO-239 to studs for ladder line.

Model 1115d - Isolation/ Choking 1:1 Balun, 3-54 MHz, 5kW

Balun Designs LLC - When Performance Counts & Quality Matters

www.balundesigns.com

Mount it at feedpoint with short jumper.

 

[Jim5570091]

Looks great. Thanks.

 

[fourstringburn]

Looks great. Thanks.

I just realized I only use the single core choke BALUN and not the dual core on my beam antenna. While the dual core in theory can have a much higher choking impedance, I recalled reading different viewpoints about if they really do in practice and some suggest these types can actually work against each other and cancel out some of the chocking impedance.

That's why I went with the tried and true single core choke BALUN.

 

[fourstringburn]

Here's some good reading on different types of chokes.

Ham Radio Site - {Different Kinds of Chokes}

DJ0IP, NJ0IP, Spiderbeam, Antenna, Antenna Tuner, Matchbox, Balun, Rob Sherwood

www.dj0ip.de