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Ämne
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REMINDER!
We will remind you of the Grimeton Radio/SAQ transmission on VLF frequency 17.2 kHz, CW, with the Alexanderson 200 kW alternator on “ALEXANDERSON DAY”, Sunday, June 28th, at 09:00 UTC and12:00 UTC (11:00 and 14:00 SVT).
We will start tuning up some 30 minutes before the message.
There will be activity on amateur radio frequencies during the day with the call SK6SAQ.
Frequencies:
– 7,035 CW or 14,035 CW
– 3,755 SSB
– 145,700/145,100 VHF FM repeater (R-4/RV-56)
QSL to SK6SAQ via SM bureau.
QSL-reports on SAQ transmissions are kindly received:
– E-mail to: info@alexander.n.se
– or via: SM bureau
– or direct by mail to: Alexander – Grimeton Veteranradios Vaenner,Radiostationen Grimeton 72
SE-432 98 GRIMETON
S W E D E NThe radio station will be open to visitors from 08:00 to 14:00 UTC (10:00 to 16:00 SVT).
Welcome!
Also read our web site: https://www.alexander.n.se
Yours
Lars Kalland
SM6NM
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Patrik Eriksson – the mad inventor (moved from comments)
I guess I am one of the closest listeners to the great alternator; just a wee bit north of Gothenburg. But, my receiving equipment is somewhat extraordinary – a self-built analog music synthesiser!
As the transmitter frequency is well within the bandwidth of my audio processing circuits I realised that they could possibly be used as a VLF receiver. One of the synthesisers VCOs were used as a local oscillator, tuned to something like 17,8 kc/s (btw, ‘the grand old lady’ is far more stable than my music oscillators. There is no room for a mammoth flywheel in here…
) A long wire as an improvised antenna was then connected through the synths preamplifer, then mixed with the VCO into the ring modulator unit (4-quadrant multiplier). The resulting signal at a few hundred Hz was then fed through a 4-pole low/bandpass filter and on to the loudspeakers.Now, I’m just a musician and audio engineer with limited, to say the least, experience in antennas and frequencies above hearing range. I had a result, but just barely. With careful listening and tuning of the filter I could hear most of the transmission, but almost drowned in other forms of noise in my setup. My next plan is to spend the time until christmas transmission to learn and design a proper antenna, and a better (less noise, more gain) preamp cirquit.
Such a lovely reason to learn and look deeper into analog topics in this digitalised world!Also, I have to admit to a wee bit of ‘cheating’; I did have the dutch SDR online too, as a backup plan / reference. 😉
I will stay tuned…
Cheers,
/Patrik