DDE/SDR# add-on
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SDR# support for WXtrack

I am very grateful to Ian Gilmour (MM6DOS) for providing an add-on to the excellent SDR# program which allows WXtrack software to control the receive frequency in SDR# - required for best results to correct for the Doppler shift when working with satellites.

Note: WXtrack version 3.8.24 or later is required.

What is provided

In the Zip archive are two support DLLs - one specific to SDR# and one for general DDE support.  The former is from Ian Gilmour (MM6DOS), and the latter from Brian Gideon at the Codeplex project.

Version History



First user-released version



A new generic parser routine since all seem to send the elements in different order. Added a preset for SatPC32.  All 3 tested and still working.  In theory any "WiSP compatible" software should now work as long as it provides SN, AZ, EL and DN. Other items are ignored.



Support for SDR# mode setting, minor GUI bug fixed.  Please note that this version is " as received".



Support for SDR# with the v4.6 .Net runtimes, versions 1362 and later.



Support for SDR# with the v4.6 .Net runtimes, versions 1411 and later.

Downloading the software

You can download the software here: DDETrackerV4Binaries.zip.  Please note the licence for using the NDde.dll software in the file NDde-licence.txt, taken from: http://ndde.codeplex.com/license 

You can download the source here: DDETrackerV4Source.zip.  Please respect Ian's copyright on the source code.  You do not need the source code to run WXtrack with SDR#.  Ian writes: Please consider this code donated to be made freely available however you wish.  I only ask for it to remain under an MIT style license with an attribution to myself and Bob Rich @ SDR# project.  This request is included in the Zip archive as the file: SDRSharp.DDETracker.dll-licence.txt.

Once downloaded, remember to right-click the Zip file, select Properties, and press the Unblock button.

Current downloads

Mark Hammond reports that V5 "seems to work great with SatPC32".  Thanks for the report, Mark.  I expect it's therefore likely to work with other software as well.

Please note that for the mode setting to work correctly, it now requires that the mode sent over DDE be an UPPER CASE string, which has broken working correctly with WXtrack.  There is now an update to WXtrack to resolve this issue and allow mode switching to work as expected.  Please be sure to use WXtrack 3.8.38 or later.  You need to ensure that the Tracker, Options, "DDE upper case box" is checked.

Adding the required files to your SDR# directory

You can double-click on the Zip file you downloaded to display the files in the Zip archive.  Get a second Windows Explorer and point it at the directory where you installed SDRsharp.exe.  You should see a number of files there.  Now get the two DLL files from the Zip archive:


and drag and drop them to your SDRsharp.exe directory.  They should replace files of the same name in that directory.

Adding the entry to the configuration file

You need to edit the SDR# configuration file to tell SDR# to look for the new plug-in.  The configuration file is actually a plain text file, so it's edited with Notepad, but it has the file name:


Open this file in Notepad, and locate the section named <sharpPlugins>.  Insert this new line in that section:

<add key="DDE Tracking Client" value="SDRSharp.DDETracker.DdeTrackingPlugin,SDRSharp.DDETracker" />

So that before your edit the section might have looked like:

    <add key="Wave Recorder" value="SDRSharp.WavRecorder.WavRecorderPlugin,SDRSharp.WavRecorder" />
    <add key="Frequency Manager" value="SDRSharp.FrequencyManager.FrequencyManagerPlugin,SDRSharp.FrequencyManager" />
    <add key="Freq Mgr" value="SDRSharp.FreqMgr.FreqMgrPlugin, SDRSharp.FreqMgr" />

and after the edit it looks like:

    <add key="Wave Recorder" value="SDRSharp.WavRecorder.WavRecorderPlugin,SDRSharp.WavRecorder" />
    <add key="Frequency Manager" value="SDRSharp.FrequencyManager.FrequencyManagerPlugin,SDRSharp.FrequencyManager" />
    <add key="Freq Mgr" value="SDRSharp.FreqMgr.FreqMgrPlugin, SDRSharp.FreqMgr" />
    <add key="DDE Tracking Client" value="SDRSharp.DDETracker.DdeTrackingPlugin,SDRSharp.DDETracker" />

Note that a new install of SDR# may overwrite the .config file, requiring you to repeat the edit described.

If using a recent version of SDR# (mid-2014 onwards) you will need to place the entries in the new file: plugins.xml  instead (from a posting by Ian Sharp).

Using the add-on

Note: WXtrack version 3.8.24 or later is required.  Download WXtrack here.

Open WXtrack and select the Tracker, Options menu.  

From the Tracker Model list, check the CX6DD WiSPDDE Client box.

On the Radio tab, select which satellite you want to control the receive frequency in SDR#.  If you have the auto-switch function working in WXtrack, the satellite controlling the receiver will also auto-switch if you have the Link frequency auto-switch box checked.

Now start SDR#, and on the DDE Tracking Client (plug-in) panel, press the Connect button.  There should be no need to alter the settings, but the correct values are:

WxTrack: checked
Application name: WxTrack
Link topic: Tracking
Link item: Tracking

You may need to switch back to WXtrack to see the new frequency setting.  You can edit the file Radio.ini in your WXtrack directory (using Notepad) to select the frequencies for each satellite.  The format of the file is documented at the start.


Q: I just installed the tracking plug-in for SDR# (v1.0.0.1450).  It shows the frequency from SatPC32 in the plug-in, but does not change the main "tuned frequency".
A: I solved it, in Scheduler configuration there had to be "radio_tracking_frequency_On".  (from Arto Oksanen)

Issues outstanding

I have had one report that the update from SDR# 1443 to 1444 has broken something when using SatPC32, and that SDR# must now be run in administrator mode to fix this.  [I don't believe this should be required, though.]

Building from the source

I have managed to build a DLL from the source files which Ian provided, although I have not yet been brave enough to actually use the DLL I built!  I used the free Microsoft Visual Studio Express C# to compile.

  1. The source Zip file contains one directory, DDETracker, which you should expand to a location on your hard disk.
  2. Create a directory underneath that one, named ReferencedDLLs, which will contain two files from the SDR# working directory.
  3. Copy (don't move!) the files SDRSharp.Common.dll and SDRSharp.Radio.dll from your working SDR# 1114 directory to the newly created ReferencedDLLs directory.
  4. Open the file SDRSharp.DDETracker.csproj with MS VC# 2010.
  5. On the right-hand side of the screen is a section labelled Solution Explorer.  Expand the section labelled References.  You will see two files listed with yellow flags against them - the two files listed above.  Right-click, Remove those two files.
  6. Right-click the References header, and select the Add Reference... option.  Use the Browse tab to select the two files you copied to your own ReferencedDLLs directory, and add them.  You may need to repeat for each file.
  7. Now select the Debug menu, Build Solution (or press F6).  You should be able to build the DDETracker DLL, which wll appear in a directory: obj\Debug.
  8. To build a release version, look at the Properties panel on the lower right-hand-side of the VS window, and change the Active config to Release|X86.

Good luck!

Copyright © David Taylor, Edinburgh   Last modified: 2016 Jul 21 at 16:44