From time to time, OnAllBands presents our readers with a fresh look at a proven DX Engineering product to provide a clear and concise explanation of how it can make an immediate impact on station performance. Today, we’re exploring the many advantages of using the DX Engineering Ferrite Bead Choke Kit (DXE-FBC) to simply and effectively create RF isolation at an antenna feedpoint or feedline termination.
For many years, well-informed hams have been using this type of feedline bead choke in lieu of cheap, poor-performing baluns and inline chokes with insufficient ferrite. The DXE-FBC Ferrite Bead Choke Kit provides the right mix and number of ferrite beads, along with shrink tubing, so you can make the same chokes employed by world-class contest and DX stations.
The kit includes 40 toroidal mix-31 solid ferrite beads. Install these beads on a user-supplied coaxial cable (prior to connector installation*) to build a high-performance RF choke with a high common mode impedance (CMI) over a wide frequency range—1.8 to 54 MHz.
Given the simplicity and raw performance of this 40-bead choke, its comprehensive RF features and benefits should become familiar to every radio antenna experimenter or amateur operator.
Ten Reasons to Use DXE-FBC Ferrite Bead Chokes
- Reduction in Received Noise: These chokes provide extremely effective rejection of stray RF and human-produced noise that collects on the outside of the coaxial cable shield. They also prevent interference from getting inside of the feedline at the feedpoint of the antenna. The results include a reduced level of received noise, which can profoundly improve reception and copy of weak signals.
- Reduced RF on the Shield: The DXE-FBC kit keeps transmitted and received RF on the antenna from “leaking out” onto the outside of the coax shield.
- Better Antenna Performance: This is achieved by keeping RF currents equal on the antenna to maintain optimal antenna pattern for the best possible transmitting and receiving performance.
- Eliminate Phasing Errors: This is the proper type of choke for a phased array element feedpoint. The DXE-FBCeliminates phasing errors caused by an inline wound-on-toroid choke or the totally ineffective coiled coax (ugly balun) that only functions on one random HF frequency that is often not in a ham band.
- The BEST 1:1 Balun: Achieve the best possible results on 50 ohm, 75 ohm, and other 0.405-0.425 inch OD coaxial cable feedlines.
- Multiple Uses: Superior to wound-on-toroid box baluns, the Ferrite Bead Choke Kit has a range of applications, including dipoles, Yagis, verticals, and phased array element feedpoints, as well as at feedline terminations at remote switches, at the end of feedlines, and in the shack.
- Essential for Elevated Feedlines, including elevated feedpoint antennas or array elements.
- Strongly Recommended for ALL Feedlines, especially those run on or above ground. Works well in combination with transformer or voltage baluns.
- Ideal for Antennas and Equipment with Direct Feedline Connections.
- Prevents Multiple Problems: Benefits include prevention of tuning and RFI problems, erroneous meter readings, and improper equipment operation.
The simple installation of the DXE-FBC Ferrite Bead Choke Kit onto your 0.405-inch OD coaxial cable (RG-213U, 400MAX, LMR-400, RG-8U, RG-11U, RG-214, et. al.) is done prior to connector termination. The kit’s 40 1.125-inch-long ferrite toroidal beads have a 0.500″ ID and 1″ OD. Slide on the supplied 48-inch-long heat-shrink tubing and use a heat gun or hair dryer to secure the ferrite beads in place and to provide long-lasting weather protection.
* Yes, the superior overall performance of the DXE-FBC Ferrite Bead Choke completely offsets the trouble of cutting off a coaxial connector, installing the kit, and then installing a new connector. It really is that good!
Check out Suggested Parts on the DXE-FBC website page for replacement coax connectors. To preserve maximum performance, optional Bead Choke Standoff Kits are used to mount the DXE-FBC Ferrite Bead Choke the proper distance away from metal antenna booms or masts.
Also visit DX Engineering for Color-Coded Ferrite RF Noise Reduction Kits containing toroids and snap-on beads in various mixes and configurations. Specific kits are made for RFI suppression of AC/DC generators, AM broadcast, linear amplifiers, and HF base stations.
You’ll also find ISO-PLUS Ethernet RF Filters for the suppression of electromagnetic interference and reduction of common mode RFI to and from Ethernet cables used between computers, printers, routers, transceivers, and other devices.
For a great primer on ferrite chokes and their uses, read this OnAllBands article by Ward Silver, N0AX.
