BreakPoint
Listen to World Heritage Grimeton Radio (SAQ) on Sunday 30 June
Here is something for the weekend 🙂
Hook up a loop/coil / long wire (with amp, migth involve soldering) to your soundcard and and listen to the mechanical radio 😄
LabVIEW implementations wellcome 😄
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Alexanderson Day 2013
Alexanderson Day 2013 takes place on Sunday 30 June.
We will try to send a message with the old alternator at 09:00 UTC and 12:00 UTC. We start the transmitter about half an hour before we send the message. The frequency is as usual 17.2 kHz CW.
http://alexander.n.se/in-english/saq-transmission/
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More links:
"Antennas successfully used by US stations reach from a 4 foot loop portable on Port Mahon Beach (Dover, Delaware) to a 100 meter long zepp at 22 meters height at Marietta, Ohio. Find your own solution and don’t give up after the first try!"
http://www.vlf.it/harald/strangerec.htm
http://on3jt.byze.be/saq-grimeton-reception-in-2005
http://en.wikipedia.org/wiki/Grimeton
And here is a mechanical receiver:
http://www.wireless.org.uk/mechrx.htm
Yearly update 🙂
Transmissions on Alexanderson Day Sunday 29 June 2014
SAQ will be on air on Sunday 29 June. We try to start the transmitter soon after 08.30 UTC so there will be a test signal from about 08.40 UTC and a message will be sent at 09.00 UTC. A similar procedure will start at 11.30 UTC and the message will be repeated at 12.00 UTC. The frequency is 17.2 kHz CW.
Links see first post.
Only three times a year, a 1.6m diameter rotor is turning somewhere in Sweden, sending out a signal at 17.2kHz. (The last of it's own)
And you can detect that just with the soundcard of your PC. and a simple loop antenna, catching the magnetic field 😄
and this time, I wat to put my name on this list 🙂
So last time I use a degausing coil from an old CRT TV and HDSDR, this time I still have one week and already build my loop from 10m CAT6 cable and a 100nF Cap , feeding the mic input of my soundcard. The loop should be vertical mounted with the plane directed to sweden.
A wooden door will hold two turns of my old network cable, giving me 16 turns of wire. Fixed with clamps for outdoor tablecoth allow easy fine adjustments. 🙂
The capacitor(s) are in parallel with the loop and build a resonance at about 17.2 kHz. tuning the cap is done with the attached vi..
hold on ....
I forgot to mention: This time it should be done with LabVIEW!!
Starting with the simoultanious sound input output example I simply modified to send out noise and show a power spectrum.
So we also need a small sending coil. (I used a coil also harvested from the CRT TV with 22Ohm in series, however any coil should work.)
Next is a CW morse decoder...
I used a mp3 sound example converted to wav. these example a mixed down to 800Hz but shouldn't make a big difference at this stage ....
A LOOP IN detect the CW and convert it to positive or negative timestamps. looking at the distribution chart, the di and daa could be separated.
Well ... to a certain level..... still under development 😉
that's it so far.
Next post will be my wav for testing.....don't know if lithium allow it
Small update...
after some more crashes than wanted
here is a Listening software (still have to implement the morse decoder )
BUT you can listen to some CW if you select 800HzCW ... extra kodos for the first who decoded it 😄
Right 🙂 I knew I can count on you 🙂 🙂
So here is a version with decoder 😄
Maybe some day I can decode it by hearing it. So ignoring the time to learn LabVIEW, drawing the decoder in LV was faster 😄
So software is almost done 🙂
Loop Antenna(s) ready 🙂
Maybe I add a high pass and try a audion like loop undamping with one or two PNPs ..... ther wasn't any solding involved by now 😞 😄
The LOCK-IN would allow to track the frequency .... just use the phase information
Need to make some nice icons ...
