Super DARN- is the interesting signal from UDXF discussion.

After some discussions, it became known, that the mysterious signal, about which we were spoken about in previous post is Super DARN (Finland).

Here is some details about this signal:

Super DARN

Super Dual Auroral Radar Network

An awesome example of Super DARN signal, send by RadioKoteg.

Author: SergUA6

Band Width ~5900-6000 Hz

Low Range hopping

RX mode source IF record

Sonograms:

pic.1 Generall view

pic.2 Detalization
pic.3 Detalization

Super DARN - there is developed enough international network for studying of an upper atmosphere and an ionosphere (Super Dual Auroral Radar Network) regions. The signal of one of radar of this network is represented in this case. The signal is curious enough, as possesses rather narrow spectrum of radiation, that is not characteristic for various probing systems. As a rule, spectrum's width of such systems, is located 20-80 kHz and higher limits. In generall, the measured parametres have relative/conditional character as can vary depending on tasks.

Many thanks to Leif Dehio for help with identification of the signal.

An interesting signal from UDXF conference discussion.

The very interesting signal, which record has been represented by Mike, appeared in UDXF conference.

The record itself, is ~2 minute I/Q file, with capacity 16 bits, the size of the file is nearby 80-90 mbyte.

Actually, there are many various signals in this record, we have marked some on the general spectrogram.

General view.

Presence of two chirps seemed very interesting to us. That has allowed to measure key parametres and to find out some curious nuances.

There is an interesting gaps(breaks), in the same positions, on two independent chirps.

In generall, the basic interest, certainly represents, not absolutely clear/understandable system, which is well visible on this spectrogram and designated on the general sonogram by green colour.

Unfortunately, on this record, it is impossible to tell precisely what width of a spectrum has this signal. Presumably it can be about 20 kHz. Nevertheless, it is well visible, that the signal has FHSS signs. It is also rather not difficult to receive key/basic parameters. It is well visible that the nature of impulses, practically in all bursts, is absolutely identical. That is strange enough, if the system is intended for real information transfer.

We are still have difficulty to classify this signal. Firstly, there is not enough data - the only one record. In the second, we didn't have similar records before. Besides, the subject of interest has too blurred limits(boundaries) and relatively weak level, plus it is liable to considerable selective fadings.

At the conference, also the other signal is discussed. The parameters of this signal, differ from the first signal, but both these signals have similar impulse nature, and close structure (an alternation of the small identical bursts). Probably, there are a lot of such signals in the air, all these signals can be different, but they are very interesting signals observe to.

PSK: INMARSAT Satellite

INMARSAT Satellite

INMARSAT AERO. OQPSK, Br-10500

The perfect example of INMARSAT AERO, send by RadioKoteg.

Author: SergUA6

Band Width ~10500 Hz

Low Range ~750 Hz, in this example only!

Baud Rate 10500 Hz

n-Ary (PSK/MPSK) OQPSK, constellation looks as square PSK-8

Count of Carriers single mode

Carrier frequency 6079 Hz, in this example only!

ACF 500 ms

RX mode SSB

Sonograms:

pic.1 Generall view

pic.2 Baud rate

Diagrams:

pic.3 Typical characteristics of OQPSK and other half-modes.

pic.4 ACF

pic.5 View of the signal in VMW

Pictures:

pic.6 Phase constellations

INMARSAT AERO - INMARSAT is using wide enought line of different protocols. In this record, it is presumably AERO-H. The signal is very bright. All the parameteres of this signal can be easily determined.