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The story behind the DRM-Log Plotter
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Back in 2005 Digital Short Wave Radio was something entirely new to me. In fact, I had never heard about it until then. It was first when I was contacted by Håkan Widenstedt at Teracom in Sweden who asked me if I could monitor Radio Sweden's DRM tests from Hörby in southern Sweden when my interest in DRM began. Håkan assigned me the location: "Empfangsanlage Biberstein SUI -- 47N24'51.6'' 08E04'30.6''" . Cool.
The evaluation software we used in those days was the DRMcalc which uses the DreamLog.txt file from the DReaM software to present the graphs:
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Carsten Knuetter's DRMcalc 6.3
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The early DOS version
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In my opinion, to see only Audio and SNR in the logs was a bit scarce, so I took data from the more detailed DreamLogLong.csv instead. My DRM-Log Plotter project started in April 2005. At that point it was created with Quick Basic, which created executable files that were run in DOS (Disk Operating System) mode. The project was named "DRMshow" at first until I noticed that Microsoft had an application of some sort called drmshow, so I later renamed mine to "DRM-Log Plotter" to avoid Bill's kill-machine.
The DOS version of DRMshow presented plots not only for Decoded audio and SNR but also Doppler and Delay in a rather crude format with a simple time scale on the X-axis from 0 to 100% rather than in minutes. The first result looked like this:
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An early DOS version of the DRM-Log Plotter, called DRMShow
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This particular log was taken on 2nd January 2007 and shows the reception in Switzerland of Deutsche Welle from Sines in Portugal. Now we had Doppler and Delay added to the graph and that was an improvement. But the publishing of these plots in Internet was not easy, so I installed a Visual Basic (5.0) software which I had got free of charge from Microsoft years before to evaluate. Until then it had never produced anything but the occasional "Hello World", so I upgraded to VB 6.0 instead hoping for some improvement. VB6 did roughly the same - all my creations always ended with a little window that read "Hello World", which I thougt was very tiring.
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The first Windows version
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However, after some experimenting, the DRMShow for Windows saw the light and had now been upgraded to "Pro" and looked like this back in March 2007:
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An early version of the DRM-Log Plotter
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In this particular log it is impressing to note how well the 4 kW transmitter from Quito, Equador performed over a distance of 9760 km (6065 miles) all the way to Switzerland.
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More log formats included for different receivers
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During the following years the DRM-Log Plotter has been developed into a tool that handles not only DReaM files but also those from the SoDiRa, DRM Software Radio, Newstar's DR111 and, if you like you can emulate the DRMcalc format if you wish. The DRM-Log Plotter of 2015 looks like this:
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The DRM-Log Plotter the way it looks today
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Other features of the DRM-Log Plotter are plotting two logs on the screen, a Main Log and a Compare log. In Compare mode Doppler and Delay are left out, otherwise the screen will be too cluttered up. Logs can be saved as data to be plotted out later including all parameters.
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From Ver. 23 the Plotter supports the plotting of xHE-AAC logs
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When Voice Of America began transmitting Radio Marti in DRM with the newest xHE-AAC encoder, the DRM-Log Plotter did not work properly. After some initial work the Ver. 22.2.6 could plot the Radio Marti files to some extent. Now, six months later using various logs from China National Radio, MOI Kuwait and TDA Algeria the plotter supports different Bitrates and Frame formats. The newest version of the DRM-Log Plotter Version 23.2.12(5th September 2020) can be downloaded from the Plotter Download page.
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The DRM-Log Plotter with xHE-AAC support in September 2020
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Publish to the DRM Forum or to your Twitter account
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In the Set-Up one can decide how to publish the logs, DRM Forum only, Twitter only or both. In case "Both" was selected, the following window will appear:
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Option Publish to either the DRM Forum or to Twitter
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Create custom tweets for Twitter
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In this window it is possible to look for Twitter hash tags which you may set yourself. It is also possible to create a Custom Tweet:
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The Custom Tweet Form
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Make a screenshot of the summary
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In addition to the Screen Shots of the graphs the DRM-Log Plotter also can create a Summary of the log which can either be exported as a text document or as a screen shot for Twitter.
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The Summary Form
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Make a tweet of the summary data
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From the Main Log Summary window it is easy to create a Tweet for the log. Press "Make Tweet" and a standard formatted Tweet is created and it can be extended with standard comments:
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The Automated Tweet Form
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The "Tweet" button will open the Twitter account which was entered in the DRM-Log Plotter Set-Up window.
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The Web Charts DRM-Log Plotter
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This HTML application is a stand-alone app which is used with the DRM-Log Plotter to generate HTML documents which presents a summary of the transmission as well as Decoded audio, SNR, Doppler and Delay plotted with help of the Google Charts API. This is useful if you want to present the logs in a Blog or in a Web Page. In addition to the Web Charts DRM-Log Plotter there is an FTP option available which sends the HTML file to a web server. Upon request I could provide this case by case.
The latest vesion of the DRM-Log Plotter that can be downloaded from the web also includes the Web Charts DRM-Log Plotter:
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The WEB Charts Application
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The WEB Charts About tab
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A part of the Web Charts DRM-Log Plotter
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Below is an example of the Web Charts how the curves may look when using Google Charts API. In addition to a table with data for the transmission, curves are generated by the Google Charts API. This particular part shows the Decoded Audio from BBC's transmission on 3955 kHz from 16th March 2015.
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Details of the transmission presented as a table in HTML
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The Chart showing the Decoded Audio for the BBC transmission
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A few words at the end
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I have not counted, but I have probably spent more than a thousand hours with the DRM-Log Plotter. Many ideas came from several users, which has driven the project to what it looks like today. Judging from the amount of users of the DRM-Log Plotter it seems like the project has fulfilled its purpose. However, the DRM-Log Plotter project has not ended yet. There is always something that can be improved or added.
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Last edited on 11th Sep. 2020
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