DX Engineering DXE-MC20-FC Balun and Choke Manual

Maxi-Core® 20

Baluns and Chokes

DXE-BAL-INS Rev 9a

DXE-MC20-1-1 - 1:1 Ratio Current Choke Balun

DXE-MC20-1-1T - 1:1 Ratio Current Tuner Choke Balun

DXE-MC20-C4-1 - 4:1 Ratio Current Choke Balun

DXE-MC20-V4-1 - 1:1 Ratio Voltage Balun

DXE-MC20-FC - 1:1 Ratio Feedline Choke

© DX Engineering 2020

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Introduction

The present-day DX Engineering was launched in the year 2000. To celebrate our
20th Anniversary in the year 2020 we have developed a new line of Baluns and
Feedline Chokes.

Introducing DX Engineering "Maxi-Core® 20" Baluns and Feedline Chokes.

Maxi-Core® 20 Baluns and Feedline Chokes reduce or eliminate currents on the outside of your feedline

allowing you to hear and to be heard much better. They keep more RFI/BCI out of your antenna and receiver
and transfer more of your transmitted signal to the antenna for higher efficiency, the best antenna pattern and
maximum performance.

Signaling a new era of RF performance across the 1.8 to 54 MHz frequency range, DX Engineering Maxi-
Core® 20 Baluns and Feedline Chokes handle full-legal-power-plus and provide higher common mode
impedance (CMI) across a greater frequency range than competing models and even previous DX
Engineering and Comtek models. Years of R&D coupled with major advancements in test equipment and
techniques combined with custom ferrite materials have allowed our engineering team to design the DX
Engineering Maxi-Core® 20 Baluns and Feedline Chokes.

Common mode impedance (CMI), also known as choking impedance, is a measure of how well a Balun or
Feedline Choke reduces exterior RF currents traveling through it and on the outside of the coaxial cable.
Currents that travel on the outside of the coax re-radiate signals directly to your antenna and then travel to
your receiver. Even with a Feedline Isolator (Choke) or Balun at the antenna end of the transmission line,
many times a Feedline Isolator is necessary at the transceiver side in order to squelch the noise currents
picked up by the feedline on the way to the radio.

Modern testing methods clearly show that coiled coax, sometimes known as an “ugly balun,” and
inexpensive baluns provide minimal CMI over just narrow frequency segments of the HF range.

Maxi-Core® 20 Baluns and Feedline Chokes have high CMI across the AM Broadcast band and the HF/6M
spectrum, which is essential to provide sufficient suppression of unwanted transmitted and received RFI/BCI
current on the feedline shield exterior.

Optional mounting brackets are available for use on wire antennas or for verticals, Yagi and beam antennas.
See the Suggested Parts tab after clicking "More Detail" on the DX Engineering web site on the model
Balun/Choke of interest. Each model listing provides additional specific information. Combination packages
that include balun or choke and bracket are also available.

Hear and be heard with DX Engineering Maxi-Core® 20 Baluns and Feedline Chokes!.

Optional mounting brackets are available
for use on wire antennas or for verticals,
Yagi and beam antennas. See the
Suggested Parts tab after clicking "More
Detail" on the DX Engineering web site
on the model Balun/Choke of interest.
Each model listing provides additional
specific information. Combination
packages that include balun or choke and
bracket are also available.

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Features and benefits of Maxi-Core® 20 Baluns and Feedline Chokes:

 Performance at the highest levels of efficiency in transmit or receive applications
 Reduction or elimination of transmit RFI and receive noise
 Currents on the feedline or antenna are forced equal for maximum efficiency and more symmetrical

antenna patterns

 Weather resistant NEMA enclosure with convenient mounting holes
 Four weep holes to help eliminate internal moisture
 High Quality PTFE dielectric, Silver Plated SO-239 Connector
 1/4-20 Stainless Steel Hardware

Choose superior performance from these models:

 DXE-MC20-1-1 Maxi-Core® 20 - 1:1 Current Choke Balun - For all HF-6m balanced antennas with a

50 ohm feedpoint, including resonant dipoles, loops, Yagis, beams, etc.

 DXE-MC20-1-1T Maxi-Core® 20 - 1:1 Current Choke Balun – This 1:1 "T" model is for force

feeding antennas with a tuner. Use it at the end of ladder line of any impedance or mounted on a coax fed
non-resonant antenna. This model tolerates operation at high SWR on non-resonant multi-band antennas.
Typically, for higher efficiency, this is the balun to use at the end of any impedance ladder line that is
feeding a non-resonant doublet. If higher losses are acceptable, it may be mounted on a coax fed antenna.
This model tolerates operation at high SWR on non-resonant multi-band antennas. But, in either case, not
all frequencies are available on a single dipole, as this is a choke balun, not a tuner.

 DXE-MC20-C4-1 Maxi-Core® 20 - 4:1 Current Choke Balun is for use on antennas with a 200 ohm

feedpoint and on any impedance ladder line, especially antenna systems with higher impedance. This
model tolerates operation at high SWR on non-resonant multi-band antennas.

 DXE-MC20-V4-1 Maxi-Core® 20 - 4:1 Voltage Balun is a 200 ohm to 50 ohm transformer for use on

random long-wire and OCF antenna applications. This true voltage balun is intentionally designed with
low CMI for antennas that need a transformer without RF choking for easier antenna tuner operation and
tolerates elevated SWR.

 DXE-MC20-FC Maxi-Core® 20 - 1:1 Feedline Choke – This high CMI line isolator is perfect for use

in line on 50 ohm coaxial feedlines, at the antenna, tower or shack end of the feedline.

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