Alexanderson Day named after the Swedish radio engineer Ernst Fredrik Werner Alexanderson and held either on the last Sunday in June, or on the first Sunday in July, whichever comes closer to 2 July, is the day of the open house at the Swedish government VLF transmitter Grimeton, call sign SAQ, located near Varberg. On Alexanderson Day, Christmas Eve and at other times during the year the only workable Alexanderson alternator transmitter in the world is used to transmit short Morse messages on 17.2 kHz using a 1.9 km (1.2 mile) horizontal wire antenna which should be easily receivable in all of Europe. The transmitter is preserved as a historical remnant of early radio technology and as an example of VLF (Very Low Frequency) equipment.
These transmissions cannot be received by ordinary radios because of their low frequency. Modern enthusiasts often monitor the transmissions using a PC with antenna connected to the soundcard input and appropriate free software (see below) or a short-wave receiver with an upconverter or any of several receivers designed to receive VLF transmissions directly. In recent years, Software-defined radio receivers have proven to be very useful and effective in receiving transmissions from SAQ around the world. Source: Wikipedia
Free SAQrx VLF radio receiver software:
To download the latest SAQrx VLF radio receiver software v0.98 as at January 2020 visit: http://dl1dbc.net/SAQ/ scroll down a lot and click on the blue text link. It will likely go straight to your Downloads folder.
Connect a simple Long Wire antenna (I'm using 20 metres insulated wire 5 metres high) down the garden to the microphone or line-in input to a redundant PC e.g. Windows XP that no longer receives Internet security updates. Best to use a PC not too important as excess static may damage the soundcard. 2 X 1N5406 diodes back to back and as kindly advised by Norman G8ATO of Verulam ARC a 100k Ohm resistor across the PC input as in image below enhances protection. Also, his recommendation of the 4.7nF capactor which serves as a filter. Ground using e.g. large crocodile clip via central heating copper water pipe. All components available from eBay but often sold in bulk so club together to keep cost down e.g. 1N5406 diodes £2 for ten.
I have been advised that my static protector circuit may be inadequate. (Comments welcome.) So along with the previous circuit I'm using a 2uF isolating capacitor and a mains neon indicator bulb, without the usual series limiting resistor, wired across the aerial input in parallel and in front of the back to back diodes. As advised by Marc Bruno IK1ODO: "...small neon pilot lamp (without resistor). The neon lamp is used as transient limiter, lighting when the DC voltage in antenna exceeds 120V or so. The lamp lights often during thunderstorms - be careful, high wires may be dangerous structures..."
The host of his page has many useful VLF links worthy of mention:
To test the neon indicator before installing it in the protector circuit I used 240 Volts with a 220kΩ inline series resistor for a medium glow.
If you live in a strong MW RF field then that could cause the neon to glow if fed with a long wire
I have also installed a 1M Ohm leakage path resistor at the front end of the circuit.
At time of writing this (January 2016) I must wait until next SAQ broadcast to know if my effort will work.
It did work! Sunday 03rd July 2016 08:45 UTC to 09:10 UTC approximately. Tune up and message received. Report: 439 QRM & QRN. For most purposes UTC = GMT.
Above circuit diagram installed in a project box.
Before turning on ensure all levels are LOW (you may need to attenuate the antenna signal) and be especially careful of overload if wearing headphones.
Listen to SAQ https://alexander.n.se/en/the-radio-station-saq-grimeton/lyssna-pa-saq/
Laptop is even better because you can transport it to an EMC quiet zone whilst away e.g. on holiday using internal battery not inteference inducing mains power. Also, consider to use onboard Windows Sound Recorder so that you may decode the transmission at your leisure either by ear or Morse reading software. Use the SAQrx VLF Radio to listen to the broadcast below:
Grimeton, Varberg, Sweden
Grimeton (call sign SK6SAQ) still transmits a message to the world twice a year: Alexanderson Day (Sunday end of June / beginning of July) & Christmas Eve. Times may vary. Google: "SK6SAQ" to check for updates and sign up for their E-mail newsletters.
Also, SK6SAQ may make test transmissions about 14:00 UTC the day before published broadcast.
Grimeton (call sign SK6SAQ) scheduled to transmit a message to the world on Saturday Christmas Eve 24th December 2016:
Transmit frequency 17.2 kHz
07:30 UTC Alternator started to tune up
08:00 UTC Transmission
Amateur Radio activity may usually be:
7.035 MHz CW
14.035 MHz CW
QSL via SM bureau
Check details: http://alexander.n.se/
p.s. Please be mindful that if using a conventional stand alone radio receiver (possibly with a converter) that switch mode power supplies may generate 'noise' at these very low frequencies. Consider linear power supply or battery.
University of Twente receiver:
http://websdr.ewi.utwente.nl:8901 is a receiver in Twente in the Netherlands of long wave, medium wave and short wave signals, continuously relaying these signals to the internet. To listen to SK6SAQ, do like this:
Frequency enter 17.2 kHz
Waterfall view 'max in'
Bandwidth 'CW narrow'
Check frequency 17.2 kHz
73 Bob G4PVB
p.s. Text from SAQ TX 24th December 2016
p.s. For those not able to read the Morse then there are many softwares to do the job for you via:
Or Google: 'morse reader software' or some such.
If you require an audio interface from RX to PC then here is my effort: http://g4pvb.eu5.net/psk31.htm
Here is my copy from Christmas 2016:
WEDNESDAY 24TH OCTOBER 2018 SAQ Sweden RST 337
16:43 UTC TUNE UP STARTED:
||: VVV VVV VVV DE SAQ SAQ SAQ :||
17:00 UTC MESSAGE STARTED:
CQ CQ CQ DE SAQ SAQ SAQ = THIS IS GRIMETON RADIO/SAQ IN A TRANSMISSION USING THE ALEXANDERSON 100 KW ALTERNATOR ON VLF 17.2 KHZ = THE ATLANTIC TELEGRAPH LINE WAS OPENED IN 1866 II II II II 1866 BETWEEN IRELAND AND NEW FOUNDLAND THUS CONNECTING THE TWO CONTINENTS. TODAY WE PAY TRIBUTE TO COMMUNICATION BETWEEN PEOPLE, IN A WORK FOR BUILDING PEACE. = NB IME WE NEITHER REQUEST QSL REPORTS ON THIS TRANSMISSION, NOR WILL RESPOND WITH QSL = CARDS = SIGNED OS WORLD HERITAGE GRIMETON RADIO STATION AND THE ALEK II II II II ALEXANDER = GRIMETON VETERAN RADIOS VAENNER ASSOCIATION = AR QRU DE SAQ ST II II SAQ SAQ SAQ VA
17:06 UTC END
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