2019-12-25

Idea Box: QRSS With Simple Home Made Equipment.

Some years ago, while living in the Netherlands, I made a few experiments in receiving QRSS (very slow morse) with a receiver and a computer running the SpectrumLab software under Wine in Linux.

Despite living in an apartment I had some success, but when I moved everything was dismantled.

I have still been following the developments in the QRSS activity, and I should like to get going again. Running a so-called Grabber (QRSS receiver does not take too much time out for other activities, because the spectrograms are simply up-loaded to a website for all to see.
QRSS provides a quite good weak signal performance, so it is usable for propagation monitoring, provided that there are some QRSS transmitters active.

Last time I was running a QRSS Grabber was before the time of the low cost Raspberry Pi single board computer, but these days it is an excellent candidate for running grabber software.

Now, what about receivers ? I was thinking of running a very simple, low cost receiver to begin with, e.g. a modifies Pixie kit.
The Pixie is an extremely simple 40m single frequency CW transceiver, mostly supplied with a 7023kHz crystal. On 40m it just might be capable of running a grabber on 7040kHz. The "IF" will be 17kHz, that should be within the capabilities of spectrum analysis programs for the Raspberry Pi. Alternatively, a different crystal, say 7030, 7035 or even 7038kHz crystal could be used, substantially bringing the "IF" down. If the missing image selectivity becomes a problem, a simple, single crystal filter with a 7040kHz crystal filter could be used.

To be fair, the Pixie is very low cost, a kit can be had for less than $5, so it is an excellent candidate for experiments. The design, however, is probably quite reliable, but certainly not high performance.

In the coming year I hope to have room for some experiments with QRSS, but a higher priority is getting a signal through the QO100 satellite.

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