Hi Riccardo,
Your signal is well visible here on my grabber
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
Am 26.04.2018 13:04, schrieb Riccardo Zoli:
Hi VLF,
A new carrier test is running with about 610mA.
Now, with last SL version, the PLL configuration made
by Markus seems to works well here, the phase is stable. I started this
test yesterday at about 10:00 UTC.
I'm looking for an adequate conditional statement that permits
to inhibit the audio (and the TX) in case of an excess of antenna
current drop. Any suggestion?
Yes, sure, this is what i'm using all the time here.
First you need to calculate the antenna current from the signal level
I use: s=1820*(10^((peak_a((sgf-10),(sgf+10)))/20))
s= antenna current in mA
sgf=transmit frequency (signal generator frequency)
1820 is just a calibration factor to calibrate the value to mA.
The If condition is 1, so it is executed on each FFT, which means each
200 ms.
Then i define a traget current with the parameter d: d=600 (for example)
Next i define a current limit L, say 100 mA
Now if the actual current s drops L mA below the target value d, then
another parameter e, which is a counter level, is increased.
After 200 ms the measurements are repeated and if the current is still
to low, e is increased again.
Oh and there is another parameter c, which regulates the output
amplitude.
If e exceeds a certain value (i choose 5), the c is set to 0, so the
output amplitude becomes 0.
Actually the complete procedure is much more complex, i just described
the safety function.
If you like, i can send you a usr file for TXing carriers and EbNaut...
73, Stefan
My current VLF condx attached.
All the best
73 de Riccardo IW4DXW
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