March 22, 2023


In this week’s blog we look at one of the stables in the RFS portfolio – HELIFLEX®. Designed and produced by RFS for over 70 years, our HELIFLEX solutions have been installed across the globe. Here, Gerd Bohnet, Product Line Manager Waveguide & Air Dielectric Cable at RFS talks us through the solution and how it is used.

Gerd Bohnet, Product Manager Waveguides and Accessories

A simple first question, what is HELIFLEX®

HELIFLEX is RFS’s portfolio of corrugated coaxial air dielectric cables. The HELIFLEX cables are air filled coaxial cables where the inner conductor is centered by dielectric spacers. This gives the RFS solution several advantages versus alternative options. The first is indicated in the name, HELIFLEX is so named due to the helix corrugation. This makes this cable flexible, allowing it to be wound onto a drum and manufactured in single long length pieces. This is the big advantage compared to rigid lines which can handle similar power but in shorter length and without any flexibility. Additionally, when it compares foam dielectric cables it here has the advantage of a higher power rating due to lower attenuation at the same dimension. This gives our customers a number of benefits when they select HELIFLEX for projects. 

How long has RFS offered this type of solution and how has it evolved? 

RFS began production of HELIFLEX in 1951 and has continued to evolve its portfolio of this product over the last 70 years. We are now able to offer larger cable sizes up to 8” and 9” allowing us to cater for a great range of applications. In addition to the cables themselves, we have also committed to developing a range of essential accessories together with selected suppliers to improve the deployment process and address the needs of our customers. 

Can you give an example of an application using HELIFLEX? 

The main application for HELIFLEX cables is in the broadcast sector, specifically in applications where there is a need to transport high power signals from the transmitter to the antenna with lowest possible attenuation and signal distortion. The solutions are not limited to broadcast applications, but can be used for all high power application where attenuation is an issue.

HELIFLEX has been deployed is used all over the world, how do you ensure customers get the most out of the solution? 

One of the real strengths for customers selecting HELIFLEX is that we are able to provide both the cable and the required accessories to ensure an efficient and effective solution. With dedicated accessories like clamps, grounding kits, and connectors which are optimized to our cables the customer minimized the risk of performance loss during installation and operation over the years. 

At RFS, we take great pride in the fact our solutions are built to last. As an example, RFS delivered 9” cable for the at the Wertachtal transmitter site in Bavaria, Germany to support broadcasting for the 1972 Olympic Games in Munich. From 1972 to 2013 this was the biggest shortwave broadcasting facility in Europe and is still operating 50 years later without performance degradation, demonstrating a solution that is still standing the test of time. 

What does the future hold for the HELIFLEX portfolio? 

As long as radio stations are installed, there will be a need for cable. The HELIFLEX option helps to guarantee an efficient installation with highest possible performance. RFS is one of only a handful of manufacturers specializing in this style of cable and our heritage in the space allows us to develop best in class solutions for an ongoing challenge faced by broadcasters.