The DRM-Log Plotter Story.
How it all started.














The story behind the DRM-Log Plotter

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 (R.I.P.) at Teracom 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:

In the beginning there was Dreamcalc
Carsten Knuetter's DRMcalc 6.3

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:

An early version of the DRM-Log Plotter, called DRMShow
An early DOS version of the DRM-Log Plotter, called DRMShow

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.

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:

An early version of the DRM-Log Plotter
An early version of the DRM-Log Plotter is born

In this particular log it is impressing to notice how well the 4 kW transmitter from Quito, Equador performed over a distance of 9760 km (6065 miles) all the way to Switzerland.

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:

The DRM-Log Plotter the way it looks today (Version 16 from 2015)
The DRM-Log Plotter the way it looks today (Version 16 from 2015)

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.

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:

The Publish Option to go to the DRM Forum or to Twitter
Option Publish to either the DRM Forum or to Twitter

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:

The Custom Tweet Form
The Custom Tweet Form

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.

The Summary Form
The Summary Form

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:

The Automated Tweet Form
The Automated Tweet Form

The "Tweet" button will open the Twitter account which was entered in the DRM-Log Plotter Set-Up window.

The latest version of the DRM-Log Plotter that can be downloaded from the web also includes the Web Charts DRM-Log Plotter:

The WEB Charts Generator
The WEB Charts Application

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.

Details for the transmission presented as a table in HTML
Details of the transmission presented as a table in HTML

The Chart showing the Decoded Audio for the BBC transmission

This HTML application is used 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.

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 stopped yet. There is always something that can be improved or added.

Last edited on 17th April 2015