Using HDSDR's built-in DDE client
Software defined radios supported by HDSDR version 2.0 and above may be frequency controlled via
DDE., Dynamic Data Exchange. It is used to share information between different software programs.
Having the capability to control your software defined radio's Tune or LO frequency via DDE is especiallyhelpful when dealing with Doppler correction in Satellite and EME based communications. The example
below demonistrates how to configure HDSDR and Ham Radio Deluxe's Satellite Tracker to control aSoftrock VHF Ensemble SDR for Doppler correction. It is assumed you have already successfully
configured HDSDR to work with your software defined radio. Only minor changes if any will have to bemade to the instructions below for use with other software defined radio's HDSDR supports such as the Fun
Cube Dongle.
For linear transponder satellite operators, the capability to view the entire transponder at once is aninvaluable tool. Imagine being able to view and record the entire transponder at once. The advantages aretremendous:•Quickly visually identify existing QSOs and stations calling CQ.

•Quickly identify new stations coming on the transponder as they enter the footprint.

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Quickly visually identify who is using software Doppler control.

•Record and play back the entire transponder to hear all stations on the transponder which you did not
make contact with.

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Quickly locate on the transponder stations which you have limited mutual visibility with.

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Never have to wonder if there is someone else on the transponder you could be contacting while
you're currently engaged in a QSO.

•No need to purchase an expensive full duplex all mode radio or two all mode half-duplex radios. A
half duplex radio and software defined radio, such as a relatively inexpensive Softrock VHF
Ensemble (which requires a pre-amp) or Fun Cube Dongle is all you need.

Configuring HRD SatTracker:•Download and install Ham Radio Deluxe version 5•

Run the HRD Satellite Tracking sub program•

From the top menu select Tools>>>Options•

Make the suggested in each tab below.
◦ Enter your 4 or 6 digit grid square under Your Information>>>Locator◦ DDE Local Server>>> Select Orbitron◦ Click OK on the bottom right of this window•On the top iconed menu bar click on the Satellite Defns button◦ Click Add Group on the sub-iconed menu bar that shows up◦ Come up with a name for the Title: fieldsuch as “My Satellites”◦ Now choose the satellites you want to track. VO-52 and AO-7. have linear transponders with 2mdownlinks. Visit http://oscar.dcarr.org for current status updates on various satellites.
◦ Close the Satellite Definitions Tab.
•On the main iconed top menu bar click on Next Passes, which has a blue arrow on its icon in the topmenu. You will now be able to see when the upcoming passes will over you.

•Double click on a satellite's elevation vs time graph, say VO52 which has a loud USB 2mdownlink. A new tab will open showing VO52's current foot print on Earth.
◦ On this new tab's sub-menu icon bar click on the Tuning Dial icon.
◦ VFO-A and VFO-B will apear. Double click on either one.
◦ Double click on the RX frequency of 145.900 MHz.
◦ If your SDR has a center “spur” or a lot of noise at the center frequency, you might wish to offset
145.900 MHz by 10-20 kHz, as 144.900 MHz is the center of the transponder where most of theactivity will likely take place. This can temporarily be done by using HRD's TRX slider as well.
◦ Check the RX box next to VFO-A. Checking this box will send the Doppler corrected
frequency via DDE to HDSDR.

Configuring HDSDR:•

Launch HDSDR•

Press the F7 key to bring up the Options menu•

Select DDE Client◦ Choose Orbitron for DDE Format.
◦ Click the Manually Connect button on the bottom left.
◦ You should see “Status: connection ok :)” text.
◦ Choose LO for Sync type.
◦ Click OK•

Notice HRD Satellite tracker is now adjusting your LO frequency for Doppler shift.

For 1296 MHz and above EME operation where Doppler correction needs to be considered, Moon can beselected as the satellite to track in HRD Sat tracker under the Add Group section above. HRD can be
configured to control your transmitting radio directly via CAT/CIV and send the Doppler corrected RXfrequency to HDSDR via DDE. This is an invaluable tool for quickly and automatically zero beating on
another station.

v0.1c (01 December 2011)