Overview

DX Engineering Vertical Antenna Matching Network

The DX Engineering Vertical Antenna Matching Network, DXE-VMN-1, is a custom-designed impedance matching coil that is used at the feedpoint of a low band HF quarter-wave vertical or a Hustler 4-BTV, 5-BTV or 6-BTV multi-band vertical antenna. In most ground-mounted 160, 80, 60 or 40 meter mono-band vertical antenna installations with very good radial systems and high efficiency, feedpoint impedance at resonance is naturally well below 50 ohms, typically between 25 and 40 ohms. Achieving the best SWR match to a 50 ohm coaxial cable feedline on these resonant vertical antennas usually requires this type of coil for adjusting feed point impedance.

When mounted with the included L-bracket, the DXE-VMN-1 is just under 7 in. tall. It works as an impedance matching coil, also known as a shunt coil, because it is installed in parallel with the feedline, from the antenna to ground. Plus, it connects the antenna to DC ground to bleed off, or shunt, any static electric charge on the antenna to ground. Yet, it works perfectly as an impedance transformer at HF, just like a hair pin or beta match on a Yagi, easily handling legal limit RF power.

The DXE-VMN-1 can aid in matching the low-impedance feedpoint of a multi-band antenna to a reasonable SWR in the user-selected portions of 80 or 40 meter bands without affecting the operation on the other, higher frequency bands. The DXE-VMN-1 has a special coil tap clip to make the inductance adjustment needed for the correct match.

NOTE: This matching network is not for use on 43 ft. non-resonant multi-band verticals. It cannot be used as a series coil to "load" a vertical to a lower frequency operation, especially with high power. Matching network shunt coils, loading coils and baluns cannot be used on verticals used in a phased array. Most phased vertical array systems cannot work with matched 50-ohm feedpoints, but rather require 35-ohm, natural impedance feedpoints. Therefore, use the DXE-VMN-1 only on single vertical installations.

DX Engineering Vertical Antenna Matching Network features include:
* Precision-machined coil tube
* Highest quality 12-gauge tin coated solid copper coil wire for high power handling, corrosion resistance, ease of soldering, and long-term reliability
* Custom-made silver plated DX Engineering Coil Tap Clip (extras available separately as DXE-CLIP-P)
* Custom L bracket for mounting to the optional DX Engineering Radial Plate, DXE-RADP-3
* #14 AWG stranded copper wire with ring terminals for connection to the antenna (adapt or remove as needed for other antennas)
* Stainless steel mounting hardware

When installed properly as an impedance matching coil, the DXE-VMN-1 easily handles the legal limit Amateur Radio power level of 1500 watts, 1.8 through 30 MHz.

DXE VMN-1 maximum inductance by frequency:
300 kHz - 7 MHz: 5.6uH
Up to 14 MHz: 7.2uH
Up to 21 MHz: 8.5uH
Up to 28 MHz: 8.0uH

Note: Whenever the DX Engineering "Documentation" is available, please look at the associated files for additional product information.

Documentation

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