The following is a draft of my instructions for setting up an LD-1TR with HDSDR, Ham Radio Deluxe, Digital Master 780, Virtual Audio Cable, and Virtual Serial Port Emulator for PSK-31 operation, or operation with other digital modes supported by DM-780. Although it is written primarily for LD-1TR owners, it may be helpful to owners of other SDRs which are compatible with HDSDR. Also, I used HRD and DM-780, which are no longer freeware. I will investigate no-cost alternatives, and add instructions for using them, if possible, in the near future.

This is a draft, and is not quite complete. It will be updated within the next couple of days.

PSK-31 Operation Using HDSDR, HRD, DM-780, VAC, VSPE, and LD-1TR

This document describes the steps to prepare for PSK-31 operation using the software and hardware listed above. It is assumed that all of the above software has already been installed.

HDSDR:

HDSDR is excellent SDR software which is compatible with the LD-1TR and other SDR front end hardware, including the various Softrock receivers and transceivers. It is currently the only SDR software which supports transmit operation with the LD-1TR. It communicates with the LD-1TR via the ExtIO API.

HRD

:

HRD is excellent CAT transceiver-control software, which was freeware until recently. It now costs $59.95 or more, depending on support options. In my opinion, it is definitely worth the cost if it is used to control a conventional transceiver and it may be worth the cost because of the many features it includes. However, for our purposes it is only necessary to control T/R switching of the LD-1TR via CAT commands, and there are probably software alternatives which are less expensive or free.

DM-780

:

Digital Master 780 is excellent digital mode transmit/receive software which is included with HRD. It is capable of modulating and demodulating many modes, including PSK-31, PSK-63, RTTY, Hellscheiber, CW, SSTV, and others. It controls T/R switching by sending TX and RX commands to HRD, which in turn controls the transceiver T/R switching.

VAC

:

Virtual Audio Cable can be used to connect the audio output of one application (e.g., the receiver output of HDSDR) to the audio input of another application (in this case, DM-780). It is as if there were two souncards, with a physical audio cable connecting the ouput of one to the input of the other, but without actually installing two soundcards and without a physical audio cable. It currently costs $25 – $40, and is well worth the cost.

VSPE

:

Virtual Serial Port Emulator can be used to emulate a physical COM port, to connect two applications which would otherwise communicate via a physical serial cable. It will be used to send CAT commands from HRD to HDSDR to control T/R switching. It is very simple and easy to set up for this purpose. VSPE is free for 32-bit computers, but there is a $24.95 cost for digitally-signed drivers for 64-bit computers. There are free alternatives, such as com0com, but VSPE’s setup is simpler and easier.

LD-1TR

:

A 5 Watt SDR transceiver from Lazy Dog Engineering LLC (www.lazydogengineering.com)

VSPE Setup

:

  1. Launch VSPE from the Windows Start Menu.

  1. On the Menu bare, select Device->Create to create a new “serial port”:

  1. Click “Next” to accept the defaults:

  1. Select an unused COM port name. In this screenshot, the virtual port is designated COM26, which is not in use. You may select any COM port designation shown on the selection list as long as it is not used for anything else. Do not check “Emulate Baud Rate”. Click Finish:

  1. Click the “Start” button (green arrow), then minimize the VSPE panel.

 

VAC Setup

:

VAC Control Panel

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Launch the VAC Control Panel from the Windows start menu (it is found in the “Virtual Audio Cable” folder) and set the number of cables to 2. The other settings should be as shown:

HDSDR

:

  1. Connect Make sure your LD-1TR is connected for transceive operation, as shown below. For nonvoice modes, connection of speakers or headphones to the internal soundcard is optional, and the microphone is not needed at all:

  1. Launch HDSDR (from the Windows start menu), and select ExtIO_LD1.dll as shown below, and click “Open”:

  1. When the “Select Device” dialog appears, click OK:

  2. If the “Select Device” dialog doesn’t appear, exit from HDSDR. Check the USB connection to the LD-1TR, then turn the power supply off (or disconnect the power cable) and turn the power back on (or reconnect the cable). Launch HDSDR again, select “ExtIO_LD1.dll”, and click “Open”. When the “Select Device” dialog appears, click OK.
  3. If the “Select Device” dialog still doesn’t appear, repeat steps 3 and 4 until the end of time, or else contact Lazy Dog Engineering for help.
  4. Click the HDSDR “Options” button, and select “SDR TX Support” (If it isn’t already checked):

  5. If you are successful, the following information box will appear. Read the warning, and if you are able to comply, click “Yes”. If the warning does not appear, the most likely reason is that you have not copied ExtIO_Si570 into the HDSDR installation folder. Refer to the documents for instructions.

  1. Click the HDSDR “Soundcard” button, and make the selections shown below. Use the appropriate connections for your external (radio interface) soundcard for “RX Input from Radio” and “TX Output to Radio”. “Line 1 (Virtual Audio Cable) as “RX Output (Speaker)” to connect the received audio to DM780, and use “Line 2(Virtual Audio Cable)” as “TX Input (Microphone)”, to connect PSK-31 audio from DM-780 to the transmitter’s audio input:

  1. Click the HDSDR “Options” button, select “CAT to HDSDR, and select “Port”. Then select the port corresponding to the virtual serial port you set up earlier (COM26) in this example.
  2. Click the HDSDR “Options” button, select “CAT to HDSDR, and select “Baudrate (bps)”. Select 9600.
  3. Click the HDSDR “Options” button, select “CAT to HDSDR, and select “PTT activation pins”. Select “None (CAT Only)”.
  4. Click the HDSDR “Options” button, select “CAT to HDSDR, and select “activated”.
  5. Go to the Lazy Dog LD-1 control panel (you may have to click the “extio” button on HDSDR). On the menu bar, find “TX Support” and make sure “TX Disable” is selected, this will be changed in a later step. Set the sliders as shown, so the LO Frequency is 14.063 MHz. The LO Step should be 73 kHz, and LO Phase should normally be “90 deg”:

  1. Set HDSDR’s mode to “USB”, and click the HDSDR “Start button. If you have a good antenna connected and 20-meter conditions are reasonably good, you should see some PSK31 signals between 14.07 and 14.075 MHz:

HRD

:

  1. Launch HRD from the Windows “Start” menu. If the connection dialog doesn’t appear automatically, click the green “Connect” button in the upper-left corner of HRD:

  1. Select the “New” tab. Make the settings as shown below:’

  1. Click the “Connect” button If you have done everything right, the HRD screen will be populated with various displays and controls, and the displayed mode and frequency will match the mode and Tune frequency shown in HDSDR (USB and 14.069859 MHz in this example):

  1. To confirm that HRD and HDSDR are indeed communicating via VSPE, try using HRD to change the mode to LSB and confirm that HDSDR’s mode changes to LSB. Then click the HDSDR “USB” button, and confirm that HRD reflects the mode change back to USB. This may take several seconds.

 

DM-780

:

  1. Launch DM-780 by clicking the “DM-780″ button on HRD. Click the “Soundcard” button on DM780, shown below:

  1. The Soundcard pane should appear at the left side of DM-780. Find the “Options” button at the bottom of the Soundcard pane, and click it:

  1. The “Program Options”dialog will appear. As shown below, select “Line 1 (Virtual Audio Cable)” as “Input (Receive)”. Select “Line 2 (Virtual Audio Cable)” as “Output (Receive)”. then dismiss the dialog by clicking the “x” in the upper right corner:

  1. You will now connect DM-780 to HRD. Click the “Radio” button on DM-780, which is found to the left of the Soundcard button:

  1. The “Radio” pane will appear, where the Soundcard pane was:

  1. Click the “Connect to HRD” button. The Tune frequency should appear, along with Mode and TX buttons:

  1. You should now be receiving PSK-31, if signals are present. This document does not include detailed instructions for using DM-780 (such instructions are available elsewhere), but it is interesting to start the “Superbrowser” by selecting Superbrowser->Display on the DM-780 menu bar:

  1. It is especially interesting to watch the Superbrowser when conditions are good and there are many signals. Unfortunately, at the time this is being written conditions are not good. Nevertheless, notice CO3GD calling “CQ DX” on the upper “ticker”.

Listening to PSK-31 Audio While Operating

:

You may wish to listen to the received PSK-31 audio on your headphones or speakers while DM-780 demodulates it. This is easily accomplished.

Audio Repeater (MME)

:

  1. Launch an “Audio Repeater (MME)”, found in the “Virtual Audio Cable” folder of the Windows start menu. Set “Wave In” to “Line 1 (Virtual Audio Cable)” and set “Wave out” to your preferred audio output device, headphones or speakers. Set the sample rate to 22050, and set “Channel config” to “Mono”, then click “Start”:

  1. You should hear received audio in your speakers or headphones, and DM780 should still be demodulating any PSK-31 signals. Minimize the “Audio Repeater” dialog box. Line 1 connects the received audio output from HDSDR to DM780, and the repeater you just set up sends a copy of the audio output to your speakers or headphones.

Transmitting PSK-31

:

You are now ready to try transmitting. You may wish to acquaint yourself with the “Macros” features of PSK-31 and customize your own macros, as well as entering your personal information (callsign, locator, name, etc.) to automate as much of your operation as possible. You may, on the other hand, do everything manually.

First, go the the Lazy Dog LD-1 control panel and select “TX Support->TX Enable” on the menu bar. You may minimize HDSDR and HRD to reduces screen clutter.

In DM-780, use the Superbrowser to watch for a reasonably strong station calling CQ, or one about to end a contact. When you see one, double-click on the ticker. This will bring up that particular station, as shown below:

You may select an appropriate macro, such as “Himx3 de Mex2 Pse K”. The macro automatically prepares a first transmission, all you have to do is click “Send”:

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