DX Engineering DXE-RTR-1A User manual

Receive Antenna Interface
for Transceivers
DXE-RTR-1A
U.S. Patent 8,175,546
DXE-RTR-1A-INS Revision 1b
© DX Engineering 2012
P.O. Box 1491 ∙ Akron, OH 44309-1491
Phone: [phone] ∙ Tech Support and International: [phone]
Fax: [phone] ∙ E-mail: [email protected]

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Table of Contents
Introduction
3
“An Amateur Radio Dilemma”
3
The DX Engineering Solution
3
Features
4
General Information
4
DXE-RTR-1A Receive Antenna Interface for Transceivers - Front Panel
7
DXE-RTR-1A Receive Antenna Interface for Transceivers - Rear Panel
8
Internal Jumpers
9
Connection Descriptions
10
Receiving Antenna Spacing Guidelines
11
Typical System Configurations
11
Diagram 1A -
Active Receive Antenna and Transmit Antenna
14
Diagram 1B -
Active Receive Antenna and Transmit Antenna with RX IN/OUT
15
Diagram 2 -
Active Receive Antenna and Transmit Antenna using High Power
16
Additional System Configurations
17
Diagram 3 -
DXE-NCC-1 Receive Antenna Variable Phasing Controller
with two Active Receive Antennas
19
Diagram 4 -
DXE-NCC-1 Receive Antenna Variable Phasing Controller with two
Active Receive Antennas using high power to the transmit antenna.
20
Diagram 5 -
Single Transmit Antenna System using a DXE-RPA-1 Preamplifier
21
Diagram 6 -
Single Transmit Antenna System using a DXE-RBS-1 Reversible Beverage
Antenna System
22
Diagram 7 -
Single Transmit Antenna with a DXE-RFS-TS2P Receive Four
Square Array Package
23
Diagram 8 -
One Monoband or Multi-band Vertical Transmit Antenna using a
DXE-ARAV2-1P Active Receive Antenna using the DXE-NCC-1 Receive
Antenna Variable Phasing Controller
24
Diagram 9 -
Classic T/R relay connections for separate Transmitter and Receiver with
a Single Transmit Antenna System using a DXE-RPA-1 Preamplifier
25
Diagram 10 -
Relay connections for separate Transceiver and Receiver with a Single
Transmit Antenna System using a DXE-RSC-2 Two-Port
Splitter/Combiner
26
Diagram 11 -
Relay connections for separate Transceiver and Receiver with an Active
Receive Antenna and a Single Transmit Antenna System using a DXE-
RSC-2 Two-Port Splitter/Combiner
27
Operation
28
Manual Updates
28
Optional Items
29
Technical Support
32
Warranty
32

3
Introduction
The patented* DXE-RTR-1A Receive Antenna Interface for Transceivers is a unique and simple,
multi-purpose relay unit which automatically switches the RF output antenna connector on any HF
transceiver between a receiving antenna system and a standard transmitting antenna. A manual
override switch allows instantaneous switching between transmit and receive antennas.
Designed specifically for HF transceivers which do not have a receive antenna input, the DXE-
RTR-1A enables operators to safely enjoy the improved reception of low noise receiving antenna
system. Connection to Beverages, Reversible Beverages, Active Receive Antennas, and other
receiving antennas and accessories is now possible, only with the DXE-RTR-1A.
(* U.S. Patent Number: 8,175,546)
“An Amateur Radio Dilemma”
The benefits of using separate receiving antennas for “low-band” HF operations have been known
for many years. Enthusiasts of operations below 14 MHz have learned that typical transmitting
antennas collect too much noise for reception, especially for DXing on the 160 and 80 meter bands.
Unfortunately, for over three decades, only the most expensive HF transceivers have been
manufactured with a separate receive antenna input. Even so, many older and newer “high-end”
radios do not provide for switching their reception between a receive antenna and the default
transmit antenna, nor do they interrupt the receive input during transmit. To obtain a separate
receive antenna input, certain models required optional equipment or modules which are no longer
available.
For many Amateur Radio Operators, the joy of low-noise, low-band reception with a separate
receive antenna has been out of reach. Modern, “affordable” HF transceivers have been designed
without any provision for a receive antenna connection. Otherwise very capable transceivers, even
brand new models, lack a built-in receive antenna port and relay system.
The DX Engineering Solution
The DXE-RTR-1A Receive Antenna Interface for Transceivers, offers a special antenna switching
solution, that incorporates safeguards against accidental RF transmission into a receive antenna
system. The DXE-RTR-1A may be used for switching flexibility and to protect the receiver input
during transmit for those transceivers that are so equipped.
Typical homebrew and commercial transmit/receive (T/R) relays, and other receive switching
solutions on the market, offer little or no protection to the receive antenna equipment. Transmitted
energy could damage receiving equipment if keying and timing errors or power loss occurs.
The DXE-RTR-1A is a new HF relay system that allows reception only if the unit is powered and
the keying line from the transceiver is connected. As soon as the transceiver is keyed or the DXE-
RTR-1A loses power at any time, the RF output from the transceiver is automatically diverted to
the transmit antenna connection. A very fast acting (about 4 ms) 200 watt RF capable relay in the
DXE-RTR-1A diverts the transceiver output quickly enough for QSK operation (full break-in CW)

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while listening to a receive antenna. The DXE-RTR-1A also allows instantaneous receive
comparisons between the receive antenna and the transmit antenna, with a convenient three-position
front panel switch. Indicator LEDs (Light Emitting Diodes) on the front panel allow the user to
determine at a glance if the unit is properly powered and if the receive or transmit antenna is
selected for reception and when the unit is keyed for transmission.
Features
Attractive, Heavy Stainless Steel Enclosure that won't slide on your desk
Front Panel LED Status Indicators and Manual Override Switch
200 Watt Transmit Switching Capability
Supports CW full break in (QSK)
Receive Antenna Inputs and Outputs use RCA phono and Type F connectors for safety
Main Antenna and Radio Connectors are SO-239 for ease of installation
Safe switching - automatically connects radio to transmit antenna when dc power is off
Hot switching lockout –disconnects receive antenna during transmit mode
Adds protection and antenna switching flexibility - for transceivers with receive ports
Level Limiter helps to protect receiver overload from strong received signals
RoHS compliant assembly
The DXE-RTR-1A Receive Antenna Interface for Transceivers is an attractive station accessory,
housed in a heavy, stainless-steel enclosure which matches other DX Engineering station
accessories. Cable connections to the DXE-RTR-1A are made entirely on the back panel, and all
switches and indicators are on the front panel, for a clean, easy-to-use installation.
General Information
The DXE-RTR-1A Receive Antenna Interface for Transceivers is the accessory that allows owners
of transceivers which lack a receive antenna input to safely enjoy optional receive enhancing
equipment. The DX Engineering DXE-RPA-1 Receive Pre-Amplifier may be used in-line on a
receive antenna. The DXE-NCC-1 Receive Antenna Variable Phasing Unit and the DXE-AAPS3-
1P Active Antenna Phasing System are now available for operations for RX ANT Input deprived
radios. The DXE-RTR-1A may be combined with the DXE-TVSU-1A Time Variable Sequence
Unit for high power operations at stations where the receive antenna is physically close to the
transmit antenna and for status indication of keying.
Old and new transceivers alike can benefit from the use of a high performance, low-noise pre-
amplifier to enhance reception. The DXE-RPA-1 Receive Pre-Amplifier offers dynamic range and
third order intercept performance that exceeds most top dollar transceivers. As requested by many
Amateurs worldwide, the receive only DXE-RPA-1 Receive Pre-Amplifier may now be used in-
line safely for improved reception with a transmitting antenna, when connected with the DXE-
RTR-1A.
For enthusiasts who wish to use a favorite transceiver as a receiver only, now using an RF output
connection to a receive pre-amplifier and antenna and can be virtually worry free. Accidental
transmission through the receive antenna or receive pre-amplifier need not cause concern with a
properly connected DXE-RTR-1A.

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Many owners of transceivers that have receive ports are choosing to use the DXE-RTR-1A. For these
operators it offers three benefits. First and foremost, the DXE-RTR-1A can protect the front end of
the transceiver with automatic disconnection of the receive input during transmit, preserving fast CW
break-in operation (QSK) with a 4 ms response time. Second, the DXE-RTR-1A offers a simple and
handy way to toggle between listening to receive and transmit antennas with a front panel switch.
Third, the DXE-RTR-1A has a built-in Level Limiter circuit to help protect your receiver from
damage due to strong received signals.
Most high-end transceivers, old and new, offer a receive antenna input that DOES NOT interrupt
RF or switch off during transmit, even though the receiver is muted, very quickly in full break-in
CW operation. This is a design feature which allows an operator to listen to a receive antenna,
located a sufficient distance away from the transmit antenna to prevent receiver front end damage,
allowing very fast QSK operations. However, most Amateurs who own this type of radio do not
have access to the real estate for the required antenna separation to support this type of operation.
Unfortunately, several hams have discovered these facts the hard way, after unintentionally blowing
the front end of their expensive transceiver with transmitted RF riding in on their receive antenna
feedline. Also, on many transceivers, connection of a receive antenna to the RX (antenna) IN port
requires removal of the “RX OUT to RX IN” jumper patch cable, and then the transmit antenna
cannot be heard. Recommendations for external relays and other devices have not addressed the
need for protection as well as switching options. The DXE-RTR-1A fills this need with an
attractive and versatile accessory.
For those who want to use a separate receiver or use a second transceiver as a receiver and interrupt
the receive antenna feedline when transmitting, the DXE-RTR-1A may be used as a T/R relay.
Also, monitoring the transmitting antenna with a second receiver while operating the main
transceiver with a receive antenna (SO2R application) is possible with the DXE-RTR-1A.
The DXE-RTR-1A may also be used with an optional DXE-RSC-2 Two-Port Splitter/Combiner to
share a transmit antenna between two transceivers, with only one used for transmitting, or between
a transceiver and a receiver.
Standard relays and coaxial relays that are used in a typical default receive T/R system are prone to
keying timing problems which can result in damaging receiver front-ends due to pulses or hot
switching. The DXE-RTR-1A solves that problem for vintage radio collectors and operators. Used
as a traditional T/R relay, it switches a transmit antenna between a receiver and a transmitter with
an output of up to 200 watts. The DXE-RTR-1A offers complete protection and high speed (4 ms)
receive to transmit transfer. The DXE-RTR-1A is a superior solution to old, slow T/R relays, and it
allows the safe use of an optional receive preamplifier.

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Detailed diagrams of the following applications and accessory connections are included in this
manual.
Connecting a transceiver that does not have a receive antenna input to:
DXE-ARAV3-1P Active Receive Antenna
DXE-ARAV3-1P Active Receive Antenna and transmit Antenna using high power
DXE-NCC-1 Receive Antenna Variable Phasing Controller with two DXE-ARAV3-1P
Active Receive Antennas
DXE-NCC-1 Receive Antenna Variable Phasing Controller with two DXE-ARAV3-1P
Active Receive antennas using high power to the transmit antenna.
Single transmit antenna system using a DXE-RPA-1 Preamplifier
Single transmit antenna system using a DXE-RBS-1 Reversible Beverage Antenna System
Single transmit antenna with a DXE-RFS-TS2P Receive Four Square Array Package
One DX Engineering Monoband or Multi-band Vertical transmit antenna using a DXE-
ARAV3-1P Active Receive Antenna with the DXE-NCC-1 Receive Antenna Variable
Phasing Controller
Connecting a transceiver that has a receive antenna input and receive output:
For any receive antenna system interruption of receive antenna feedline during transmit
For the versatility of switching between listening to either the receive or transmit antenna
Connecting a transmitter and receiver to the same antenna system:
Classic T/R relay connections for separate Transmitter and Receiver with a Single Transmit
Antenna System using a DXE-RPA-1 Preamplifier
Connecting two transceivers, one used for receive only, to the same transmit antenna, for
simultaneous reception.
Using an optional DXE-RSC-2 Two-Port Splitter/Combiner, a transmit antenna can be
shared for dual receiving.
Connecting two transceivers, one used for receive only, to the same active receive antenna, for
simultaneous reception.
Using an optional DXE-RSC-2 Two-Port Splitter/Combiner, a transmit antenna can be
shared for dual receiving.
Other uses of the DXE-RTR-1A are possible but not detailed in this manual:
Connecting a non-active receive only antenna to a transceiver and transmitting antenna
system
Connecting a main transceiver and a second transceiver for single operator-two radio
(SO2R) contesting.
Given the nature of Amateur Radio Operators and their interest in experimentation, there may be
many other options available when using the DXE-RTR-1A Receive Antenna Interface for
Transceivers.

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DXE-RTR-1A Receive Antenna Interface for Transceivers - Front Panel
Figure 1
PWR ON-OFF
Toggle Switch - DXE-RTR-1A power on and off. +12 Vdc power is supplied via the rear
panel center positive connector.
RX ANT - ACTIVE indicator
One Red LED (Light Emitting Diode) illuminates to indicate the DXE-RTR-1A is in the
receive mode. This LED extinguishes when MAIN ON is selected or when keyed with RX
ANT selected.
PWR indicator
One Green LED (Light Emitting Diode) illuminates to indicate the DXE-RTR-1A is powered
and turned on.
MAIN ON - RX ANT - MAIN ON toggle switch
Three position (On-On-plus Momentary) provides manual control of the DXE-RTR-1A
antenna selections.
MAIN ON (up) - Manually switches RADIO to the MAIN ANT for receiving with the
transmitting antenna. RADIO remains connected to MAIN ANT during transmit.
RX ANT (center) - Switches the RADIO to the RX ANT for receive mode and allows
automatic switching of the RADIO to the MAIN ANT during transmit.
MAIN ON (momentary on when pressed down) - Manually switches RADIO to MAIN ANT
momentarily for a fast check of reception on the transmitting MAIN ANT.

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DXE-RTR-1A Receive Antenna Interface for Transceivers - Rear
Panel
Figure 2
TRANSMIT GROUND
Isolated RCA connector - Keying line connection from transceiver or sequencer (grounding
keying line only) for automatic relay switching of RADIO from the RX ANT IN to the MAIN
ANT. This connection to the transceiver is required to enable reception on a receive antenna;
RX ANT through to RADIO with front panel MAIN ON/RX ANT switch in RX ANT position.
Note: If the keying line is shared (using a "Y" adapter)
with an amplifier or amplifier interface buffer,
then precautions should be taken to be certain
that the transceiver to DXE-RTR-1A
connection is not interrupted.
If the keying line connection from the transceiver to the
TRANSMIT GROUND connector on the DXE-RTR-
1A is lost, transmitted RF may cause damage to the
DXE-RTR-1A or receiving equipment.
This connector MUST be connected to the
grounded-on-transmit transceiver keying
line, cable shield to radio chassis ground, and
the RADIO connector must be connected to
the transceiver RF connector, cable shield to
radio chassis ground, to enable receive mode.
Positive voltage keying will not key the DXE-
RTR-1A properly.
Damage to the DXE-RTR-1A could occur by
attempting to use positive voltage keying.
Review your transceiver operation manual
carefully. Transceivers with positive keying
only must be connected to an interface buffer
to provide grounding-on-transmit keying.

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RADIO 
SO-239 connector - Transmit and receive RF connection to the transceiver or connection to
transmitter RF connector. Maximum 200 Watts transmit with MAIN ANT connected to a
suitable antenna or load. Connected, by default, to the MAIN ANT IN connector when the
DXE-RTR-1A is not powered or the MAIN ANT/RX ANT switch in the MAIN ANT position.

MAIN ANT IN
SO-239 connector - RF connection to a suitable transmit antenna or load. Connected, by
default, to the RADIO connector when the DXE-RTR-1A is not powered or the MAIN
ANT/RX ANT switch in the MAIN ANT position. Connection for high end transceiver "RX
OUT" to monitor transmit antenna through DXE-RTR-1A. Details in Diagram 1B and text.

MAIN ANT OUT
RCA type connector and F-Connector (in parallel) - Output for special applications, receive
only connection of MAIN ANT during receive mode only. Used for transmit antenna
monitoring and pre-amplification or phasing purposes only. Disconnected during transmit or
when unit is switched to MAIN ANT. See Diagrams 5 and 8.

RX ANT IN
RCA type connector and F-Connector (in parallel) - Input for receive only antenna, or from a
receive only device. May accept output from a DXE-RPA-1 Receive Preamplifier, or from a
DXE-NCC-1 Receive Antenna Variable Phasing Controller.
12 VDC
A 2.1 mm power cord is supplied with unit. The wire with the white stripes is the +12 Vdc.
Outer Connection is GROUND Center Pin is +12 VDC.
If station power is used, it must be +12 Vdc at 1 amp (fused) minimum. An optional
DXE-PSW-12D1A 120 Vac 60 Hz to 12 Vdc 1 Amp, fused wall transformer supply
is available.
Internal Jumpers
There are two internal jumpers set to factory default positions. HD1 and HD2 are jumpered by
default to the top two pins towards the HD1 and HD2 lettering on the printed circuit board for
proper operation as shown in Figure 3. This jumper configuration is used to take advantage of the
Level Limiter circuitry to help prevent receiver overload damage. HD1 and HD2 are reserved for
possible future options.
Figure 3 - Internal Jumpers
HD1 and HD2

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Connection Descriptions
The diagrams included in this manual demonstrate the wide variety of specific connections that are
possible with the DXE-RTR-1A, truly a multi-purpose device. These connections are simple and
straightforward and do not require advanced electronics skill.
Connect a regulated station power supply which provides a 1 A fused 12 Vdc to the DXE-RTR-1A
power connector on the back panel. With the included 2.1 mm power cord, the power connector
must be wired center positive. If a station power supply is not available, connect the optional DXE-
PSW-12D1A Wall Transformer.
Typical interconnections between the DXE-RTR-1A, the transceiver, antennas and accessory
equipment are made with commonly available or easily made patch cords. Plans should be made to
locate the DXE-RTR-1A close to the transceiver, so instant reception antenna changes may be
made with the front panel switch.
Receive only connections must be made with either male RCA phono style patch cords or with male
F connector cables. Custom length cables with F-Connectors installed can be supplied by DX
Engineering. If RCA phono style patch cords are used, high quality connectors should be selected
for this low-noise RF application. Inexpensive audio cables may not be suitable. RCA Phono and F-
Connectors are used on DX Engineering receive devices to help prevent accidental connection to
transmitting connectors.
Transmitting RF connections on the DXE-RTR-1A,from RADIO to the transceiver and from
MAIN ANTENNA to the transmitting antenna system, tuner or amplifier are made with standard
PL-259 patch cables in lengths that permit locating the equipment in their proper operating
positions. Custom length cables with PL-259 connectors installed can be supplied by DX
Engineering.
The TRANSMIT GROUND keying line connection to the DXE-RTR-1A must be made to enable
reception with a connected receive antenna or accessory. Keying line connection from transceiver
or sequencer (grounding keying line only) for automatic relay switching of RADIO from the RX
ANT IN to the to MAIN ANT.
This connection may be shared with an amplifier-transceiver interface buffer keying input. The
diagrams in this manual show connections to transceivers with grounded-on-transmit keying line
only.
Note: If the keying line is shared (using a "Y" adapter) with an amplifier or amplifier interface
buffer, then precautions should be taken to be certain that the transceiver to DXE-RTR-1A
connection is not interrupted.
If the keying line connection from the transceiver to the TRANSMIT GROUND connector on the
DXE-RTR-1A is lost, transmitted RF may cause damage to the DXE-RTR-1A or receiving
equipment.

11
The TRANSMIT GROUND keying line connector MUST be connected to a grounded-
on-transmit transceiver keying line, cable shield to radio chassis ground, and the RADIO
connector must be connected to the transceiver RF connector, cable shield to radio chassis
ground, to enable receive mode.
Positive voltage keying will not key the DXE-RTR-1A properly.
Damage to the DXE-RTR-1A could occur by attempting to use positive voltage keying.
Review your transceiver operation manual carefully. Transceivers with positive keying
only, must be connected to an interface buffer to provide grounding-on-transmit keying.
Receiving Antenna Spacing Guidelines
The overall benefits that receiving antenna offer is less noise. Weak signals can be heard on a
dedicated receive antenna because it rejects noise and strong stations by virtue of its design, size,
directivity and lower sensitivity.
Therefore, placement of a receiving antenna is very important. Normally, excellent results are
achieved by placing a receive antenna in a low noise environment. If possible, receive antennas
should be located at least 1/2-wavelength away from noise sources and noise re-radiating antennas.
Houses, other metal or structures containing metal, metal fencing, towers and transmitting antennas
can introduce noise into a receive antenna by proximity which may reduce the effectiveness of a
receive antenna.
However, in many cases, the physical space required for the ideal receive antenna installation is not
available to the average back yard. The following diagrams (1-7) of typical and special system
configurations show absolute minimum spacing between transmitting and DX Engineering Active
Receive Antennas. For optimal performance, greater spacing is recommended for better reception
results.
Diagram 8 shows phasing of a mono-band or multi-band vertical antenna using a DXE-ARAV3-1P
Active Receive Vertical Antenna with the DXE-NCC-1 Receive Antenna Phasing Controller. The
spacing described is 1/4 to 1/2-wavelength between the transmit antenna and the Active Receive
Antenna. This distance is based on optimal performance of the equipment described.
For in-depth receiving antenna system information, please consult the ARRL Antenna Book or
ON4UN's Low Band DXing book.
Typical System Configurations
In most cases, the operator will purchase the DXE-RTR-1A because they want to use a receive
antenna on a transceiver which lacks a receive antenna input. See the text below and use Diagram
1B for an example using the DXE-RTR-1A with a transceiver having a Receive Input and Output.
All transceivers under 200 watts output may be connected to the DXE-RTR-1A as is shown in
Diagram 1A, and all other Diagrams 2 through 9, even if it has a receive antenna input.
Diagram 1A illustrates the positions and connections to a standard transceiver for optional receive
enhancement products from DX Engineering. A simple Beverage antenna or receiving loop antenna

12
may be connected directly to the RX ANT connector on the DXE-RTR-1A. If a single DXE-
ARAV3-1P Active Receive Vertical is purchased, then the included powering device, model DXE-
FVI-1, is placed in-line in the shack between the Active Receive Vertical and the RX ANT input, or
between the optional DXE-RPA-1 Receive Preamplifier and the DXE-RFCC-1Receive Feedline
Current Choke.
Diagram 1B illustrates how to connect the DXE-RTR-1A to a transceiver using available receive
input and output connectors. For informational example purposes, here is a partial listing of the
transceivers that can benefit from connections with the DXE-RTR-1A: Yaesu FT-1000 series, FT-
1000MP/ MKV series, FT-2000 series and FT-9000 series; Icom IC-7800, IC-7700, IC-7600, IC-
765, IC-761 and IC-781.
Most high-end transceivers, old and new, offer a receive antenna input that DOES NOT interrupt or
switch off during transmit even though the receiver is muted. Also, on many transceivers,
connection of a receive antenna to the RX IN port means that the RX OUT to RX IN jumper patch
cord must be removed. Then the transmit antenna cannot be heard. For operators of these high-end
transceivers, the DXE-RTR-1A offers two benefits. First and foremost, it can protect the front end
with automatic disconnection of the receive input, preserving very fast break-in operation (full
QSK) with 4 ms response. Second, the DXE-RTR-1A offers a simple and handy way to toggle
between listening to the receive and transmit antennas with a front panel switch.
The DXE-RTR-1A RX ANT connector is used for the receive antenna system signals. The
transceiver RF output is connected to the transmit antenna or amplifier. The transceiver amplifier
keying line must be connected to the DXE-RTR-1A TRANSMIT GROUND connector to enable
reception of the receive antenna signal. Customer supplied RF patch cords must be used to connect
to the SO-239 RADIO and MAIN ANT IN ports on the DXE-RTR-1A to the RX IN and OUT
ports on a transceiver, respectively, replacing the existing jumper patch cable. In most cases these
are simply two patch cords with PL-259s on one end and male RCA phono plugs on the other end.
This connection will never allow transmitted RF into the front end of the transceiver. Since the RX
OUT carries only the received transmit antenna signals, the DXE-RTR-1A will allow monitoring of
either the receive or transmit antenna as described in this manual. This connection scheme is
applicable for the radios listed above, as well as others not listed, which offer RX IN and OUT. This
transceiver connection scheme may also be adapted for use with any of the diagramed system
configurations. If your transceiver has only a receive antenna input but no RX OUT, use the
standard connection methods depicted in Diagrams 1a and 2 through 9.
Diagram 2 shows a standard transceiver connection arrangement, with the addition of a typical RF
amplifier used on the transceiver output for high power operations. The DXE-RTR-1A and a
keyed-on-ground amplifier may be able to share the same grounding keying line from the
transceiver, but the use of an optional amplifier keying interface buffer is recommended. Do not
share the keying line of the DXE-RTR-1A with an older amplifier that uses high voltage relays.
NOTE: The DXE-RTR-1A may never be used on the output of an RF amplifier.
MAXIMUM RF power allowed through the unit is 200 watts.

13
Note: If the keying line is shared (using a "Y" adapter) with an amplifier or amplifier interface
buffer, then precautions should be taken to be certain that the transceiver to DXE-RTR-1A
connection is not interrupted.
If the keying line connection from the transceiver to the TRANSMIT GROUND connector
on the DXE-RTR-1A is lost, transmitted RF may cause damage to the DXE-RTR-1A or
receiving equipment.
The TRANSMIT GROUND keying line connector MUST be connected to a grounded-on-
transmit transceiver keying line, cable shield to radio chassis ground, and the RADIO
connector must be connected to the transceiver RF connector, cable shield to radio chassis
ground, to enable receive mode.
Positive voltage keying will not key the DXE-RTR-1A properly. Damage to the DXE-RTR-1A
could occur by attempting to use positive voltage keying. Review your transceiver operation
manual carefully. Transceivers with positive keying only must be connected to an interface
buffer to provide grounding-on-transmit keying.

14
Diagram 1A - Active Receive Antenna and Transmit Antenna
Allows use of an active receive antenna with the added receive signal
strength using a pre-amplifier.
Optional items shown include: DXE-ARAV2-1P Active Vertical Receive Antenna w/ Internal Antenna
Disconnect Relay. DXE-RFCC Receive Feedline Current Choke, DXE-FVI-1 Voltage Injector, DXE-RPA-
1Receiver Preamplifier and DXE-PSW-12D1A +12 Vdc fused 1 amp wall transformer.

15
Diagram 1B - Active Receive Antenna and Transmit Antenna
Allows use of an active receive antenna with the added receive signal
strength using a pre-amplifier connected to a transceiver equipped
with RX INPUT and OUTPUT ports.
Optional items shown include: DXE-ARAV3-1P Active Vertical Receive Antenna w/ Internal Antenna
Disconnect Relay. DXE-RFCC Receive Feedline Current Choke, DXE-FVI-1 Voltage Injector, DXE-RPA-
1Receiver Preamplifier and DXE-PSW-12D1A +12 Vdc fused 1 amp wall transformer.

16
Diagram 2 - Active Receive Antenna and Transmit Antenna using
High Power, allows use of an active receive antenna with the added
receive signal strength using a pre-amplifier.
Optional items shown include: DXE-ARAV3-1P Active Vertical Receive Antenna w/ Internal Antenna
Disconnect Relay, DXE-RFCC Receive Feedline Current Choke, DXE-FVI-1 Voltage Injector, DXE-RPA-
1Receiver Preamplifier, DXE-PSW-12D1A +12 Vdc fused 1 amp wall transformer, Ameritron AL-811 RF
Amplifier and Ameritron ARB-704 Amplifier Buffer.

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Additional System Configurations
Diagram 3 shows a new receiving application. The DXE-RTR-1A Receive Antenna Interface for
Transceivers now allows owners of transceivers which lack a receive antenna input to use a phased
receive antenna array. This diagram shows the connections for use of the DXE-AAPS3-1P
Electronically Rotatable Receive Antenna System, which consists of two DXE-ARAV3-1P Active
Vertical Receive Antennas with Internal Antenna Disconnect Relays and the DXE-NCC-1 Receive
Antenna Variable Phasing Controller using the DXE-RTR-1A Receive Transmit Relay.
Diagram 4 details the connections to optional equipment required when operating high power and
using the DXE-AAPS3-1P Electronically Rotatable Receive Antenna System. The addition of the
DXE-TVSU-1A Time Variable Sequencer Unit will produce the correct keying of all devices, to
protect the Active Receive Antennas from high power RF damage. The DXE-RTR-1A provides
connection to the transceiver which does not offer a receive antenna input.
Diagram 5 includes the exceptional DXE-RPA-1 Receive Preamplifier in-line with the main
(transmit) antenna. For many years Amateurs have been requesting a method to employ a receiving
device on their transceivers which lack a built-in preamplifier. The DXE-RTR-1A provides this
connection option. Instantaneous receive comparisons between 'preamplifier in' and 'preamplifier
out' are easily accomplished using the DXE-RTR-1A MAIN ON - RX ANT - MAIN ON toggle
switch.
Receiving with the transmitting antenna on a second transceiver or receiver while operating with the
main transceiver connected to a receive antenna is a common contesting application known as
Single Operator –Two Radios (SO2R). This is now easily accomplished by connecting the MAIN
ANT OUT line to the input of the second radio. Reception with the transmitting antenna is safely
interrupted during main transceiver transmissions.
Diagram 6 demonstrates another common use for the DXE-RTR-1A and the connections required
for use of a two direction DXE-RBS-1P Reversible Beverage Antenna System.
Diagram 7 shows how a DXE-RFS-TS2P Complete Receive Four Square Array Package for Close
Spacing to Transmit Antennas is connected to a transceiver that does not offer a receive antenna
input.
Diagram 8 illustrates the use of the DXE-RTR-1A with a DXE-MBVA-1UP Multi-band Vertical
Transmit Antenna (a monoband vertical antenna may also be used) one DXE-ARAV3-1P Active
Vertical Receive Antenna with Internal Antenna Disconnect Relay, and the DXE-NCC-1 Receive
Antenna Variable Phasing Controller. This combination allows the user to null strong receive
signals and noise in certain directions, opening up new reception possibilities. When using the
DXE-RTR-1A, the Multi-band Vertical transmit antenna can be phased with the Active Receive
Antenna using the DXE-NCC-1 Receive Antenna Variable Phasing Controller. The antennas being
phased should be the same polarization for optimal results.
Refer to the manual for the DXE-NCC-1 Receive Antenna Variable Phasing Controller (available
for viewing or downloading on the DX Engineering website) for more details on directional signal
and noise nulling.

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Diagram 9 demonstrates how the DXE-RTR-1A may be used in a classic T/R relay application with
an added bonus! The popular optional accessory for older receivers, the DX Engineering Receive
Preamplifier model DXE-RPA-1, may be used safely, for improving reception on the transmit antenna,
especially on higher frequencies. When the pre-amp is not required, it may be internally bypassed by
removing the DC power to it.
Set the MAIN ON - RX ANT - MAIN ON toggle switch to the RX ANT (center) position to connect
the MAIN ANT to your receiver. When you key the transmitter, the DXE-RTR-1A's automatic 4 ms
changeover from receive to transmit switches the MAIN ANT to the transmitter. Manually switching
the toggle switch to the MAIN ON (up) position connects the MAIN ANT to the transmitter, if desired
for tune up operations. The power limit for the transmitter is 200 watts.
The keying line from the transmitter*must be a Ground-On-Transmit type, as the DXE-RTR-1A
cannot accept any keying voltage. If the only keying line from the transmitter is a positive or negative
voltage type, then an Ameritron AMR-ARB-704 must be used in the transmitter keying line, as
shown in Diagram 9. The ARB-704 will accept any keying voltage, 12 volts positive or negative and
provides the Ground-On-Transmit keying for the DXE-RTR-1A.
A muting line from the transmitter which may provide a ground for an older receiver, cannot be
shared with the DXE-RTR-1A, as many old receivers* require the grounding of a high voltage for
muting.
*Refer to your transmitter and receiver instruction manuals for keying line and muting line
information and requirements.
In a special application with no receive antenna connections, Diagram 10 illustrates using the DXE-
RTR-1A with an optional DXE-RSC-2 Two-Port Splitter/Combiner to allow one transmitting
antenna to be shared for simultaneous receive on two transceivers or with one transceiver and one
receiver. The second radio is isolated from transmit energy by the DXE-RTR-1A. Only the main
transceiver may be used to transmit. The second transceiver that is connected to one of the DXE-
RSC-2 outputs must be transmit inhibited using either the radio's menu settings or power output
controls set to zero to prevent system damage.
Set the MAIN ON - RX ANT - MAIN ON toggle switch to the RX ANT (center) position to connect
the MAIN ANT to both radios for simultaneous reception. When you key the main transmitter, the
DXE-RTR-1A automatically changes from receive on both radios to transmit on the MAIN ANT in
only 4 ms. The strong signal heard by the second radio is at a level that cannot damage it's front end.
Manually switching the toggle switch to the MAIN ON (up) position connects the MAIN ANT to the
main transceiver, if desired for tune up operations, or for normal operations without the second radio.
The power limit for the transmitter is 200 watts.
Diagram 11 demonstrates how the DXE-RSC-2 Two-Port Splitter/Combiners can be used to split the
active receive signal to the DXE-RTR-1A and a second radio. In most low band operations, the
receive antenna system will provide superior reception compared to the transmit antenna. An active
receive antenna offers the signal-to-noise advantage that allows weak DX signals to be heard which
would otherwise be covered by noise when listening with the transmit antenna. The second
transceiver that is connected to one of the DXE-RSC-2 outputs must be transmit inhibited using
either the radio's menu settings or power output controls set to zero to prevent system damage.

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Diagram 3 - DXE-NCC-1 Receive Antenna Variable Phasing Controller
with two Active Receive Antennas
Optional items shown include: DXE-ARAV3-1P Active Vertical Receive Antennas with Internal Antenna
Disconnect Relays. DXE-NCC-1 Receive Antenna Variable Phasing Controller and DXE-PSW-12D1A +12
Vdc fused 1 amp wall transformers.

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Diagram 4 - DXE-NCC-1 Receive Antenna Variable Phasing
Controller with two Active Receive Antennas using high power
to the transmit antenna.
Optional items shown include: DXE-AAPS3-1P Electronically Rotatable Receive Antenna System (which
includes two DXE-ARAV3-1P Active Receive Antennas and one DXE-NCC-1 Receive Antenna Variable
Phasing Controller), DXE-TVSU-1A Time Variable Sequencer Unit, Ameritron AL-811 Amplifier,
Ameriton ARB-704 Buffer, MFJ-998 Antenna Intellituner, CW Key, Foot Switch, DXE-PSW-12D1A +12
Vdc fused 1 amp wall transformers and the DXE-MBVA-1UP Multi-band Vertical Antenna.