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QRSS is a low power transmission mode used by amateur radio operators in several bands, named after a Morse code signal to slow down. It consists of Morse code sent with very long timings so that the received code is detected by spectrograph instead of by ear. This has the effect of increasing the minimum SNR ratio required. It is possible to receive signals 18000 km away, on just 15mW.
I have also been experimenting with QRSS on 2 metres.
My QRSS beacon, based on my Arduino QRSS work, provides an RF output from DDS-60 (Analog Devices AD9851) which then feeds a 1 watt 10 MHz class-C power amplifier. The two combined provide an output power of around 800mW, which is more than suitable for QRSS.
Secret Nuclear Bunker
For a short while, the beacon is located at the Kelvedon Hatch Secret Nuclear Bunker (GB0SNB). A more permanent station is being worked on by Dave (G7UVW) and me. The QRSS beacon has been enclosed in a weather proof box, and protected form the elements a little. This first image shows the packing to get all the stuff, and a small power supply, inside the weather proof box. I wanted to get the power supply inside to both protect from the rain and to create a little heat inside the box. The Bunker site is remote, and the beacon on the top of a hill, where the temperature is frequently below 0 Celsius - any warmth we could collect is therefore good!
Once it had been thoroughly tested, the lid was tightened down, and I begun to calibrate the temperature. As the inside of The Shack is much warmer than outside, it was necessary to take this thermal difference into account. Something which I initially did wrong and required another trip to the site to put right! You can also see how it's raining quite hard here!
Finally, this last image shows the final resting place for the beacon. It's underneath a porta-cabin (a temporary building structure) which affords some level of shelter from direct rainfall. Then, it is under a plastic water container, which has had the side cut out of it; this reduces the wind chill on the beacon by shielding it from cross winds at the top of the hill. Inside this box, the beacon is wrapped in protective polythene to try and add a little more thermal insulation (this insulation is also part of the issue of why we had to re-calibrate the thermal drift offsets).
It's not a pretty sight, but it certainly works well. The antenna is a temporary dipole, made from previously used wire, RF adapters and 10 metres of RG58/U coax back to the beacon - all well taped up! You can just make out the dipole in the image below.
And one more for luck: Dave (G7UVW) with the laptop we used to amend the frequency offsets. Thank god he volunteered as I had left my laptop at work.
As mentioned previously, my 1W PA for 10MHz will put out about 800mW on 30 metres QRSS band. With the Arduino it is possible to create many different kinds of signal. My QRSS signal is three triangles and M1GEO in DFCW Morse code; 5 Hz shift with a 6 second dot length, on approximately 10.140,050 MHz. The image below is a locally captured copy of my transmitted signal. It is repeated continually.
Earlier versions used ramps instead of the triangles, which I believed were more easily identifiable; however, due to the use of slant-CW (people encoding Morse code into forward and reverse slashes) it is more useful to use triangles.
Please send any reports to my email address, using the Contact Me link.
I have had a few reports of spots on people's QRSS Grabbers. The first comes care of Sorin (YO7CKQ). He says:
I received today your QRSS beacon on 30 meters band. RIG here: ICOM IC756 PRO III, inverted L antenna, USB interface and ARGO software. You can see here some print-screen.
A total distance of 1847 km, from my JO01CN to KN15PA.
This one I noticed on the PA0TAB QRSS Grabber, found here. It's a little bit weak and with some QSB.
This shows a much stronger reception at the PA0TAB grabber. Note the signal is not in order, but all parts of it fully visible. The triangles break up the Morse code.
A total distance of 473 km, from my JO01CN to JO33HF.
This signal, again weak was noticed on OZ9QV Grabber, found here. Again weak with QSB.
A total distance of 912 km, from my JO01CN to JO65CP.
This signal was emailed to me by SA2BRJ from his grabber, found here.
A total distance of 1793 km, from my JO01CN to KP03CT.
This signal was emailed to me by Paolo, IZ1KXO, from his grabber.
A total distance of 2006 km, from my JO01CN to JM76.
This one I noticed on the Big Ears Grabber run by Vernon (VE1VDM), found here. There is a weaker station mixed in with us.
A total distance of 4582 km, from my JO01CN to FN85IJ.
These spots were emailed to me by Pete, ZL2IK, via the KnightsQRSS mailing list.
A total distance of 18188 km, from my JO01CN to RF74CI. Very pleased!!
These spots were emailed to me by Bill, W4HBK, via the KnightsQRSS mailing list. The first is a short 10 minute spot. The second is a 4-hour long-grab. It shows how strong reception was through out the period (as well as showing drift!).
A total distance of 7238 km, from my JO01CN to EM60KJ.
I noticed that I appeared on I2PHD's Argo Homepage in the image showing the application running. I decided to add that to the list, as it was a nice copy.
A total distance of 963 km from JO01CN to JN45SL.