Chilly temps

koudhe
Upper graph: temperatures (red=IR, blue=contact). Lower graph: mbar. We had a few cloudless days which caused the chill.
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Current set-up

This is my current set-up in the shack, transceiver FT-991, microham keyer, power supply, wspr beacon, receive antenna control box, headset, mike, PC running SDRsharp, airspy/spyverter. In the background you hear RA3QVQ calling.

Last update: 27-nov-2016

SDR frequency calibration

The airspy SDR has a somewhat temperature stabilized oscillator, I say somewhat because it needs re-calibration every time you turn it on. So how do you do that? I rely on 4 or 5 frequency standards on the HF and the VLF, decode them in CW and I interpret the spectra. You can adjust the PPM correction of the airspy and the spyverter separately, and this procedure needs to be repeated once per day or so if you want any accuracy. Some references for the time standards are (there are more of them, but I use these):

The SNR for all time standards is between 30 and 35 dB, occasionally there is some QSB. Below you see the observed spectra as seen on 19-nov-2016 at 8:30.

img_0051
RWM at 14996 kHz
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RWM at 9996 KHz
img_0053
DCF77 at 77.5 kHz
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MSF at 60 kHz