QRSS Grabber

I was invited to join in on some tests to report how well (or if at all) a low power MEPT (Manned Experimental Propagation Transmitter) beacon was being received at my location. I had done something similar a long time ago, long enough that I had forgotten the basics and needed to revisit the software, radio settings etc.

Not having too much time available before the scheduled tests I searched the Internet and discovered I2PHD’s QRSS viewer program, “Argo”.

The installation and setup of Argo was very straightforward and using the existing digi-mode interface I was receiving  QRSS signals on 30M.

10.140Mhz 2013-11-12 Argo SA6BSS

I was now in a position to “see” the many different modes being used by stations to test propagation, their antennas and vertical vs horizontal polarisation, these being just a few examples of the reasons why people are running these low power beacons.

Having run tests before, using WSPR, I knew that there were several very useful sites on the Internet that enabled you to see where your signals were being received and  gauge what’s happening within a very short period of time, e.g. see the effect of changing between two antennas.

With QRSS the reporting is done in a different way. Yes, the Internet is still used but people use what’s known as a “Grabber” to view a snap-shot of what is happening.

What is a “Grabber”?

Basically it’s a setup that will continuously capture (or Grab) a snap-shot image showing what has been received over a period of time. Typically this capture is taken once every 5 to 30 minutes. These captured images are then automatically posted to a website so that QRSS /MEPT experimenter’s can see how far their signals are reaching.

The Challenge…

I only had a day or so before the tests were to begin so my challenge was how could I join in and have my own Grabber up and running. What did I need? How do I automate the uploads etc Doing some research I quickly found that the common way was to use FTP (File-Transport-Protocol) to upload the captured images to a suitable web-site.  But I then found some references to using Dropbox and its built-in synchronisation tools to take care of the upload of the captured images.  As an existing Dropbox user it occurred to me that I already had all that I needed to possibly make this work, apart from a very small piece of HTML code needed to present the data.

What’s needed to set up a Grabber?

  • A connection to the Internet.
  • A Dropbox account.  (See note below)
  • A working receive setup using Argo to produce the captures.
  • A small piece of HTML code to provide the front page of your Grabber.

How does all this fit together?

The Dropbox client needs to be installed and working on the PC that is running Argo.

Dropbox provides you with a “Public” folder that is going to be used to publish the captures and hold the front-page of your Grabber web site.  If you do not see a “Public” folder then use the Dropbox help / search to address this.

Within Argo go to the Capture settings and configure it to save the capture file to the Dropbox “Public” folder that is on your PC. Configure Argo to create a capture every 300 seconds and start the capture process. Now access your Dropbox folders on the Internet and make sure that the folders are being synchronized and you can see the captured image. Once you are happy that a new capture is being uploaded to your Dropbox “Public” folder every 5 minutes the next step is to create the HTML to display the image.

The screen shot below shows how / where to do this.

Argo Capture Setup Screen

The key settings to note in the above example are the file name used for the capture – this needs to be the same name that you specify in the HTML file later and the sequence number should be locked.

The HTML file is used to provide some basic information on the page and automatically refresh the captured image.

Here is some very basic HTML that will provide a simple page for the Grabber:

<!DOCTYPE html>
<html>
          <head>
                       <meta http-equiv="refresh" content="300">
                       <title>your-callsign QRSS (Part-time) Grabber</title>
                       <style>
body { text-align: center; }
                       </style>
          </head>
          <body>
                       <h1>your-callsign QRSS (Part-time) Grabber</h1>
                       <h2>Monitoring frequency shown in capture</h2>
                       <h3>(Please check status below to see if online.)</h3>
                       <br>
                       <br>
                       <img src="https://dl.dropboxusercontent.com/u/your-account-id/Captures.jpg" width="1100" height="700" alt="Grabber Image">
                       <br>
                       <br>
                       <p>The capture updates every 5 minutes and the page will auto refresh</p>
           </body>
</html>

You will see that I am not an HTML programmer, (the code was put together and run through an on-line tool)   🙂   Should you choose to use this code then you will need to replace the parts highlighted in blue with your own callsign, Dropbox ID and file name used for the capture file. The HTML file should be saved to the Dropbox Public folder. It is the Dropbox Public URL for this file that people will use to browse to your Grabber.

The image below shows the end result:

G4HSK QRSS Grabber

My Grabber is online here.  (will open in a new Window / Tab)

Hints and Tips

It’s important that people can easily see what frequency you are monitoring and if your Grabber is currently on-line. This can be done easily within Argo by adopting the following procedure:

  • At the start of a monitoring period set the Argo status to “Online” and frequency offset in the calibration menu to reflect the band, before setting Capture to “on” and then press “Capture now”.
  • At the end of the monitoring session set the Argo status to “Offline”, press “Capture now” and then set Capture to “off”

The screen shots below show how / where to do this.

Argo Settings

Conclusion

QRSS / MEPT is yet another fascinating part of our hobby. Thanks to authors of programs such as Argo it is very easy to join in and see what is happening at the very bottom of most of our amateur bands. The software building blocks used to put this together are all freely available on the Internet. It’s very interesting to see the effects that propagation and things such as aircraft reflections can have on the received signals. That’s before you take into account the low power being used.

My Grabber is only on part-time, the radio used is an FT-847 with a W3DZZ inverted-V antenna.

What’s next?

Over the coming months I hope to do the following:

  • Build a QRSS transmitter using one of the many kits that are available today.
  • Improve my Grabber so that it provides an archive of captures.
  • Look at using the RaspberryPi and an SDR Dongle to provide a low cost and energy efficient 24/7 Grabber.

Acknowledgements:

  • Alberto, I2PHD for providing Argo, his QRSS viewer program.

 

Drop Box Account

Please be aware that what is described here requires you to have a Public Folder as part of your Dropbox account. Dropbox accounts created after October 4th 2012 do not have a Public Folder by default.

There was a work round that enabled you to manually “enable your Public Folder” but it would seem that this no longer works which is a great shame for this particular use of Dropbox.