LDG DTS-4/4R Desktop Coaxial Switch / Remote LDG Electronics 1445 Parran Road, PO Box 48 St. Leonard MD 20685-2903 USA Phone: 410-586-2177 Fax: 410-586-8475 ldg@ldgelectronics.com www.ldgelectronics.
LDG DTS-4/4R Desktop Coaxial Switch / Remote Table of Contents Introduction Jumpstart, or “Real hams don’t read manuals!” Specifications Getting to know your DTS-4 1 2 2 2 About the Radio Sense feature Installation Operation 5 6 7 Selecting an antenna 7 Grounding all inputs 7 Setting Radio Sense mode On and Off 7 Application Notes Remote Control Protocol Technical Support Warranty and Service Feedback 7 8 11 11 11 Introduction Congratulations on selecting the LDG DTS-4 desktop coaxial switch.
Jumpstart, or “Real hams don’t read manuals!” Ok, but at least read this one section before you transmit: 1. Attach the RF input jack (center connector, marked TX) to your transmitter or transceiver with a 50 ohm coaxial jumper cable. 2. Attach your antennas to the other RF ports. 3. Connect a 12 volt power supply capable of providing 500 ma to the 2.5 x 5.5 mm coaxial power jack (center positive). 4. Press a front panel button to select the desired antenna.
Getting to know your DTS-4 Your DTS-4 is a quality, precision instrument that will give you many years of outstanding service; take a few minutes to get to know it. On the front panel there are four buttons and four LED indicator lights. The four buttons select the four antennas connected to the rear ports. Pressed in pairs, they select special functions. The red LEDs show which antenna is presently selected. For special functions, they blink in groups of two or four.
The 2.5 x 5.5 mm jack coaxial DC power connector is on the right. The ground connection is via the wingnut. The radio sense input is a second 2.5 x 5.5 mm coaxial jack, and the control cable is a 1/8" stereo jack; the control cable is included with the DTS-4R remote.
The DTS-4R remote is smaller than the DTS-4, but has the same four switches and four LED lights on the front. On the back, it has the same power, radio sense and control jacks, but no coax connectors. About the Radio Sense feature Radio Sense is an exclusive LDG feature that automatically grounds all inputs when you turn your radio off. A sense line connects the DTS-4 to any DC out port on your radio providing at least 2 volts DC at 1 ma; most modern radios have at least one such DC output.
Installation The DTS-4 and -4R are intended for indoor use only; they are not water resistant. If you use them outdoors (Field Day, for example) you must protect them from rain. Position your DTS-4 in a convenient spot on your operating desk. If you are using the DTS-4R remote, you can position the DTS-4 switch anywhere within reach of the control cable.
Operation Caution: High RF voltages may be present on internal components when transmitting. Never operate your DTS-4 with the cover removed. Your DTS-4/4R has no power switch; it powers up when you plug it in. The relay associated with the selected antenna is energized and draws current all the time. Operation is exactly the same whether you use the DTS-4 directly, or the DTS-4R remote. Selecting an antenna Never attempt to change antennas while transmitting.
Many modern transceivers have an "auto off" function, allowing you to program the rig to turn itself off after a specified time of no use. Using this function along with the Radio Sense function of your DTS-4 insures that the rig will be protected even if you forget to turn it off. If you walk away from your radio and forget to turn it off, the rig will switch itself off after the specified time. With Radio Sense mode on, the DTS-4 will then automatically ground all inputs, protecting the rig.
Remote Control Protocol The control port of your DTS-4 is, in fact, a serial TTL I/O port compatible with protocol that is standard with PC serial ports. This section documents the control protocol; you can write your own software to control the switch. The protocol below describes the dialog between the DTS-4R remote and the DTS-4 switch. Under PC control, the PC program you write would take the place of the remote.
Codes sent by the DTS-4R remote to the DTS-4 switch R 00 - Remote is telling main unit that buttons 3&4 were pushed – user wants to ground all antennas. R 01 - Not used. Remote doesn’t give the command to ground all. R 02 - Remote tells main unit that button 1 is selected – user wants to select antenna 1. R 03 - Remote tells main unit that button 2 is selected – user wants to select antenna 2. R 04 - Remote tells main unit that button 3 is selected – user wants to select antenna 3.
Care and Maintenance Your DTS-4 switch is essentially maintenance-free; just be sure to observe the power and voltage limits discussed in this manual. Never attempt to change antennas while transmitting; always switch in receive mode. The outer case may be cleaned as needed with a soft cloth slightly dampened in a mild household cleaning solution. As with any modern electronic device, your DTS-4 can be damaged by temperature extremes, water, impact or static discharge.
