DX DXE-RXSHARE User manual

RX Share Audio Switch
DXE-RXSHARE
DXE-RXSHARE-INS Revision 0
© DX Engineering 2018
1200 Southeast Ave. - Tallmadge, OH 44278 USA
Phone: [phone] ∙ Tech Support and International: [phone]
Fax: [phone] ∙ E-mail: [email protected]

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Introduction
Multi-operator contesting is challenging, especially
when a pair of operators are unable to hear what the
other operator is hearing. DX Engineering presents an
elegant but simple solution with the “RX SHARE
Audio Switch” –a flexible switching device that
allows two operators to hear exactly what they want to
hear, whenever they want to hear it. Audio from two
separate radios or one shared radio can be controlled by either operator’s three-position rocker
switch to select the specific audio they want fed to their stereo headphones. With the RX SHARE
placed between each operator, these selections can be changed independently by each operator
quickly and easily, at will and on the fly, with the light-touch rocker switches. The RX SHARE has
been extensively tested and used in competition by experienced, world-class contesters.
Multi-operator contesting in the “Multi-Two” or “Multi-Single” category often involves
simultaneous use of separate radios on a single band or on two different bands. The “run” operator
calls CQ and makes a constant string of contacts on one frequency. Meanwhile, the second operator
searches for new stations. Limited to transmitting only one signal at a time, the ops take turns as
soon as a new contact becomes available. Using the RX SHARE in the SEPARATE RADIOS
mode, each operator may choose to listen to the Radio 1 audio or the Radio 2 audio in both ears. Or,
at any time either operator can listen to the audio from one radio in each ear, allowing better
coordination and fewer interruptions. This translates to a higher QSO rate, higher scores and less
operator fatigue!
A single-operator using two radios in “SO2R – Single-Op, 2 Radios” mode has similar needs. The
operator may want to focus on just one of the radios, listening to the same audio in both ears. Or
the operator can hear the audio from each radio in one ear, allowing simultaneous CQ-ing and
tuning for new contacts. Advanced operators can even manage two pileups at once on different
bands! Doing these things effectively requires the easy, intuitive audio control provided by the RX
SHARE.
When one radio is shared by two operators, common during Field Day or training activities, the RX
SHARE is placed in the SHARED RADIO mode. Both operators can share the receive audio or
audio from a sub-receiver, if available, can be selected by either operator. The RX SHARE
provides a convenient way of splitting the audio output of a single radio.

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In a contest situation, using a transceiver equipped to split the audio feed from the MAIN and SUB
receivers to the left and right headphone channels, each operator can choose to listen to either the
MAIN receiver or the SUB receiver in both ears, or to hear the MAIN in one ear and the SUB in the
other ear. One operator will be able to hear when a new station is ready to be worked, or when the
other operator is going to work them.
Using the DXE-RXSHARE provides complete control of the radio audio feed to two separate
stereo headphones. Audio from typical radio headphone jacks to the DXE-RXSHARE input phone
jacks are quickly and easily connected with user supplied patch cables with 1/4 inch (6.35 mm)
stereo phone plugs at each end. The unit features two sets of stereo headphone outputs including 1/4
inch (6.35 mm) and 1/8 inch (3.5mm) stereo jacks to accommodate headphones or headsets with
either type of plug - you’ll never hunt for an adaptor again! Audio levels are controlled by the
transceiver AF Gain controls.
The DXE-RXSHARE is built into a heavy steel and stainless steel chassis with four large rubber
feet, so it will not slide around the desk when the switches are operated. The switch panel is clearly
marked for every configuration and operating scenario.
RX SHARE Audio Switch Features and Specifications:
Quick connections from radios to RX SHARE via 1/4 in. stereo audio input (patch cables
required depend on transceiver headphone jacks and cable length desired)
Four stereo headphone output connections available –two of each size for each operator-
1/4 inch (6.35 mm) and 1/8 inch (3.5 mm) –extra headphone outputs may be used for
recording purposes
Center rocker switch to quickly choose the RX SHARE mode, SEPARATE RADIOS or
SHARED RADIO
Two separate and silent rocker switches at ideal height to make independent operator audio
selections
Both operators may select audio from Radio 1, Radio 2 or both in SEPARATE RADIOS
mode
Both operators can select audio from MAIN or SUB or both in SHARED RADIO mode that
supplies MAIN and SUB receiver audio separately to headphone L and R
Unit stays in place on desk during use - Large, heavy stainless and powder coated steel
chassis weighs 3.75 lbs. and measures 10.50 x 2.50 x 3.25 in. (WHD)
Stud and wing nut (#10) on rear stainless steel panel for station grounding
All connections on rear panel for proper cable management and a clear operating desk
Passive audio device requires no DC power
Internal jumpers allow audio impedance selection for different radio and headphone
combinations
DX Engineering brings innovation and convenience to contest stations, club operations and multi-
radio ham shacks. The DXE-RXSHARE Audio Switch is ready to supply just the right audio for
your operations.

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Additional Parts Required, Not Supplied with the DXE-RXSHARE
Stereo capable headphones
1/4 inch (6.35 mm) or 1/8 inch (3.5 mm) stereo audio jumper cables to connect the RX
SHARE to the radio stereo headphone jack.
Station ground connection cable
Manual Updates
Every effort is made to supply the latest manual revision with each product. Occasionally a manual
will be updated between the time your DX Engineering product is shipped and when you receive it.
Please check the DX Engineering web site (www.dxengineering.com) for the latest revision manual.
Installation
Installation is straight forward. The rear panel on the RX Share is shown below with an example
showing connection from the RX SHARE to the headphone jacks on two Icom-7610 radios and
connection to two Heil headsets. Additionally, there is a connection for the station ground to help
avoid any ground loops in the audio lines.

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Internal Jumpers
There are 9 jumpers inside the RX SHARE Jumpers H1 through H9. Access to the inside is done by
removing the four Phillips head screws that hold the case together.
Audio Impedance Jumpers H2-H9
The audio impedance jumpers select different winding configurations of the audio isolation
transformers to vary input and output impedance. Most radios and headphones will not require
changing jumpers H2-H9 from their default 150 ohm position. If the headphone audio is loud
enough and does not require turning the receiver AF GAIN controls to an extreme position, you do
not need to move the jumpers.
Jumpers H2 & H3 are for Operator 1 output audio from the RXSHARE.
Jumpers H4 & H5 are for Radio 1 input audio to the RXSHARE.
Jumpers H8 & H9 are for Operator 2 output audio from the RXSHARE.
Jumpers H6 & H7 are for Radio 2 input audio to the RXSHARE.
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The jumpers must be moved as a pair - both in the 150 ohm or both in the 600 ohm positions or
there will be no audio output.
If you have high-impedance headphones with low audio levels, move the output audio jumpers from
150 ohm to 600 ohm.
If your receiver audio output is low at normal control settings, move the input audio jumpers from
150 ohm to 600 ohm.
If the operators are using headphones with greatly different impedances or the operators have large
differences in hearing sensitivity, experiment with different settings of the jumpers to find the best
balance. It may be easiest to simply have both operators use the same type of headphones.
Ground Jumper H1
The ground jumper is provided to allow control of input and output audio
grounding. The default is for the jumper to be in the INPUT position so the
input audio common circuit is connected to the enclosure. (The enclosure also
has a ground terminal on the back panel for connection to the station ground
system.)
All stations have different configurations of wiring and RF field strengths vary greatly so in some
cases, moving the jumper from the INPUT to the OUTPUT, connecting the headphone common
circuit to the enclosure or removing the jumper entirely may avoid RFI to the audio. The audio
isolation transformers break the direct path for RF between the input and output circuit. No
combination of ground jumper setting will damage the RXSHARE or any connected equipment in
any way - feel free to experiment if you experience RFI in the audio.
Troubleshooting Audio Problems
A sinusoidal 60 Hz (or 50 Hz outside the US and Canada) tone (i.e. "hum") is most likely caused by
a magnetic field from a power transformer or ac wiring. Move audio cables away from the source
of the field and minimize cable lengths to reduce hum.
A sharper "buzz" at 120 Hz (or 100 Hz) is caused by rectified ac power or currents flowing on the
ac neutral of your power wiring. Bonding equipment to a station ground bus or directly from
enclosure to enclosure is most likely to reduce buzz.
Cross-talk between the audio outputs of each radio may be due to the audio common conductor of
the radio-to-RXSHARE cable being broken or too light. Use good-quality shielded cables to avoid
cross-talk. Bonding of the radios to a common ground bus or directly together also reduces cross-
talk.
If RF is being picked up in the headphones, first check that the headphone common conductor is not
broken or compromised. Moving the RXSHARE internal ground jumper from INPUT to OUTPUT
may help. Keep cable lengths to a minimum, as well.

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NOTES:

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Technical Support
If you have questions about this product, or if you experience difficulties during the installation,
contact DX Engineering at [phone]. You can also e-mail us at:
[email protected]
For best service, please take a few minutes to review this manual before you call.
Warranty
All products manufactured by DX Engineering are warranted to be free from defects in material and
workmanship for a period of one (1) year from date of shipment. DX Engineering’s sole obligation under
these warranties shall be to issue credit, repair or replace any item or part thereof which is proved to be other
than as warranted; no allowance shall be made for any labor charges of Buyer for replacement of parts,
adjustment or repairs, or any other work, unless such charges are authorized in advance by DX Engineering.
If DX Engineering’s products are claimed to be defective in material or workmanship, DX Engineering shall,
upon prompt notice thereof, issue shipping instructions for return to DX Engineering (transportation-charges
prepaid by Buyer). Every such claim for breach of these warranties shall be deemed to be waived by Buyer
unless made in writing. The above warranties shall not extend to any products or parts thereof which have
been subjected to any misuse or neglect, damaged by accident, rendered defective by reason of improper
installation, damaged from severe weather including floods, or abnormal environmental conditions such as
prolonged exposure to corrosives or power surges, or by the performance of repairs or alterations outside of
our plant, and shall not apply to any goods or parts thereof furnished by Buyer or acquired from others at
Buyer’s specifications. In addition, DX Engineering’s warranties do not extend to other equipment and parts
manufactured by others except to the extent of the original manufacturer’s warranty to DX Engineering. The
obligations under the foregoing warranties are limited to the precise terms thereof. These warranties provide
exclusive remedies, expressly in lieu of all other remedies including claims for special or consequential
damages. SELLER NEITHER MAKES NOR ASSUMES ANY OTHER WARRANTY WHATSOEVER,
WHETHER EXPRESS, STATUTORY, OR IMPLIED, INCLUDING WARRANTIES OF
MERCHANTABILITY AND FITNESS, AND NO PERSON IS AUTHORIZED TO ASSUME FOR DX
ENGINEERING ANY OBLIGATION OR LIABILITY NOT STRICTLY IN ACCORDANCE WITH THE
FOREGOING.
©DX Engineering 2018
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