DX Engineering DXE-RF-PRO-1B Instruction Manual

RF-PRO-1B®
Active
Magnetic
Loop
Antenna

DXE-RF-PRO-1B

DXE-RF-PRO-1B-INS Revision 1

1200 Southeast Ave. - Tallmadge, OH 44278

Phone: [phone] ∙ Tech Support and International: [phone]

Fax: [phone] ∙ E-mail: [e-mail]

© DX Engineering 2020

Introduction

The DX Engineering rotatable DXE-RF-PRO-1B Active Magnetic Loop Antenna is designed for
reception of signals over the range of 100 kHz to 30 MHz. The RF-PRO-1B® can be mounted to a
pole, mast or any flat surface. The included very high dynamic-range low-noise preamplifier is
designed for minimum intermodulation distortion in the presence of very high-level signals that
would normally overload most preamplifiers. This rotatable loop antenna is receive ONLY.

Features

 Same technology and quality as Pixel Technologies and InLogis loop antennas
 Unique Loop architecture provides enhanced performance
 Magnetic loop that rejects near field electrical noise
 Up to 30 dB rejection of locally radiated noise compared to whip

antennas

 Figure eight directivity and deep nulls to further reduce interference

from local or distant signals

 Very low IMD, 27 dB Low-Noise Clifton Laboratories Norton

Preamp insures good performance in both strong and weak signal
environments

 Useable coverage range: 100 kHz to 30 MHz
 Rejects power line noise
 Rugged construction, easily mounts to a pole or flat vertical

surface, 3/4 inch dia. aluminum loop, supplied with preamplifier,
power inserter and DC power supply

 No manual tuning necessary
 No Home Owners Association problems; low profile, easy to camouflage and works at a few

feet above ground level

 Modular design for easy installation and maintenance
 Internal transmit / receive relay disconnects the antenna / preamplifier from receiver when

transmitting

Antenna Design

The RF-PRO-1B® Loop Antenna consists of a rigid 3/4 inch diameter light-weight aluminum loop
and a balanced broadband preamplifier that is housed in a separate enclosure mounted close to the
antenna on its mast bracket. A 20 volt DC regulated power inserter unit is provided. The antenna
and preamplifier has been designed to permit the use of 75 ohm cable (RG-6 is recommended and is
available from DX Engineering). For best results the antenna should be positioned a minimum of 15
feet away from any buildings or other sources of interference. The loop antenna may be rotated to

take advantage of the directional properties of this type of antenna.

Not Your Father’s Loop Antenna

Based on the work of Dr. Carl Baum for the U.S. Air Force his “Moebius Strip Shielded Magnetic
Loop Antenna” architecture outperforms much larger antennas. Dr. Baum was a Senior Scientist at

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the U.S. Air Force Research Laboratory and is the recipient of several awards from the IEEE
(Institute of Electrical and Electronic Engineers) for his work.

Developed for a classified U.S. Air Force project involving the measurement of EMP (Electro
Magnetic Pulse) from nuclear weapons, this loop design has wide application to antennas for low­noise, interference-free radio reception over a wide frequency range. The designer of this magnetic
loop antenna version coupled this antenna to a custom made low-noise preamplifier originally
developed by Clifton Laboratories.

Magnetic Loop Antenna Advantages

Most active antennas are the whip type and respond mainly to the electrostatic-field portion of an
electro-magnetic radio wave. This Magnetic Loop responds primarily to the magnetic-field and this
ensures high rejection of nearby
electric-fields. The intensity of the
electric field is usually higher than
the magnetic-field when an antenna
is close to interference sources such
as TVs, florescent lamps, power line
wiring, etc. By rejecting the electric­field there is a reduction in local
interference compared to other types
of active and passive antennas.
Interference reduction is further
enhanced by the deep nulls of the
antenna’s 'Figure-Eight' directivity
pattern that can be used to null out or
reduce interference coming from a
specific local or distant direction. The electrical field is often much stronger than the magnetic field.
When lined up properly the loop will enable better copy for weak signals which could not be copied
by other antennas.

Intermodulation

Some active antennas generate intermodulation products which can appear as spurious signals
interfering with reception. This interference or second and third order intermodulation is caused by
non linearity in the preamplifier, producing signals which are usually the sum and difference of
strong stations and their harmonics. The RF-PRO-1B® Loop (DXE-RF-PRO-1B) has been
specifically designed to reduce intermodulation products to a minimum. The third order intercept
point is typically +48 dBm (OIP3) and the second order intercept point is greater than +100 dBm
(OIP2 typically 110 dBm). The 1 dB compression point of this preamplifier is +27 dBm making the
levels of the intermodulation products generally far below the atmospheric and man- made noise.

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Caution:

 This is a Receive-Only Rotatable Antenna. Do not connect it to a transmitter as it will be

damaged and void your warranty

 Do not inadvertently connect the (To Preamp) +20 VDC output of the power inserter

to your receiver’s antenna input as your receiver may be damaged

 When operating with nearby transmitting antennas, follow the instructions to avoid over-

driving (or damaging) your receiver’s input or damaging the loop’s low-noise preamplifier

 The DXE-RFCC is not recommended for use with the DXE-RF-PRO-1B since there is

large amount of current drawn by the RF-PRO-1B which will cause a severe voltage drop if
the RFCC is used. An alternate solution would be to use #31 ferrite cores to create a
common mode choke with nine wraps of coax

General Information

Positioning the Antenna

This antenna has a directional

‘Figure Eight’ pattern with two

deep 25- 30 dB nulls, so for
maximum daytime low-angle
ground wave reception of a desired
signal it should be oriented so that
the plane of the loop rests
perpendicular to the ground and
should, if extended, pass through

the general location of the signal’s

transmitter. At night, for reception
of high- angle sky waves this
antenna is less directional and the
nulls are far less prominent.

To take advantage of the directivity of this antenna, it should be mounted on a light duty rotator. For
best results it should be located as far away as possible from any metal objects that could distort or

shield the antenna’s reception like gutters, downpipes, metal plumbing and aluminum foil backed

thermal insulation. It can be positioned indoors or outdoors at least 5 feet above ground level, but
for best results it should be as far as possible from sources of interference such as AC power cables,
cat 5 network cables, fluorescent lights, light dimmers, computers and flat panel TV’s. If located
outdoors it can be camouflaged with shrubbery. Ideally, a location outdoors at least 20 feet away
from any buildings will yield superior results. It can be mounted to a pole or attached to a flat
surface or wall via the included L-bracket and clamps.

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