Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

appropriate balun/connector for wideband biconical antenna

appropriate balun/connector for wideband biconical antenna

appropriate balun/connector for wideband biconical antenna

I'm constructing a biconical antenna which is to operate in the 30MHz-3GHz frequency range (yes, its sizable!). I'm curious as to the best type of balun to implement as well as the best connector system to use.

Find attached a diagram of the antenna. Side-length is 30cm, and conical half-angle is 45 degrees. The radio receiver is located below (where the coaxial cable is leading to).

I was thinking about using an 'ugly/common-mode choke balun' which essentially involves covering part of the coax with ferrite beads.

Any ideas will be most appreciated.  

RE: appropriate balun/connector for wideband biconical antenna

You probably don't even need the ferrite bead choke. Assuming symmetrical build and 360-degree contact of the shield to lower element, there would be nothing inherent to cause currents on the outside of the coax cable. Of course, if it was installed in an area with high levels of lower frequency RF, then you feedline might act as a monopole and in those circumstances a common-mode choke might help. But that's more of an EMI fix than a balun.

The interface to the feedline is the only tricky part of the build. Ideally you would have a machined assembly that meets the cones, and mounts the RF connector (probably N-type). The design should be constant impedance, including consideration of the dielectric properties of any insulators used. Electrical contact should be 360-degree.

Once you have the center piece made, the rest is easy.

RE: appropriate balun/connector for wideband biconical antenna


RE: appropriate balun/connector for wideband biconical antenna

Bicones never need baluns unless you feed it from the side. Just stick your coax in there. VSWR at the high end of the band might head towards 3:1.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close