Recently, I came across the different sign-on ceremonies of different transmitters. The idea is to understand this workflow in which obviously several stages of the transmitter are switched on consecutively. See at the top one example, where Voice of Turkey is swithcing on their transmitter on 9880kHz in five steps within about three seconds.
The diagram was made with Simon Brown’s unique software SDRC V3. I used the Signals Analyser module, providing a (needed!) time resolution of down to just one millisecond, or 1000 values of level vs. frequency in just one second! These data (CSV) had been exported and visualized in QtiPlot software.
I would like to encourage other people to join these observations. One goal can be toi fingerprint no only a transmitter, but also the workflow of the people at the transmitter. Please refer to this website for a database of broadcasters and their transmitters plus galore of associated data.
In the meantime, I already observed a couple of different workflows/transmitters. Please keep in mind that all these measurements (better: estimations), of course, are prone to fading. You may also see some effects during sign-on in the spectrogram, see below.
Since Marco Polo, combinations of Italian and Chinese had proven fruitful. The Dragonfly RX-666 is such a combination or, at least, a very special “kind of”. It is a 16bit SDR, ranging 1 kHz to 30 MHz in a row with 16 bit resolution – plus some extra above 32MHz (1.5/1.7GHz) by the help of an R820T2-chip of RTL-SDR fame, but 8 bit only. Priced not much over US-$ 200 (if that) at some ebay sellers, it is a real gamechanger, offering for the first time 32 MHz streaming via USB3.0 at 16 bit resolution to ensure a competitive dynamic range.
It has been built around LTC2208 chip and seems a clone, a twin or a pirate piece of a concept, literally layed/laid out by Oscar Steila, IK1XPV, an electronics engineer from Turin. Über-DXer Bjarne Mjelde has diven deep into the story and the receiver itself. I don’t want to repeat what he found out in only my own words. You simply must read his story here, and I can stress each and every word of it.
In this blog, I may add only some audio clips to give an impression of the reception quality in Northern Germany on the evening of August 11 and the morning of August 12, 2020. Antenna, as always, is the professional active dipole MD300DX, vertical with 2 x 5 m legs. Recordings were made with HDSDR software, but replay done with SDRC V3. Both, Bjarne and Oscar, helped me to get the SDR flying at all. Without their friendly hand, it would have been only another heavy paperweight on my desk …
Now for some twelve audio clips:
The range above 32 MHz is covered by an R820T2-chip at maximum streaming bandwidth of 8MHz only. Please see below a screenshot of a part of the FM broadcast band: