Tag Archives: Monitoring

SDR Console V3: Signal History and six RX Panes!

KPL

NEW: The Receivers’ Pane on top covers spectrum and spectrogram of up to six demodulators – look at different modes and bandwidths. Also new: “Signal History” at the bottom.

Simon Brown, G4ELI, has further developed his software SDR Console which has become THE platform for a real bunch of very different SDRs. The new public preview has two more exciting features:

  • “Signal History” takes the signal strength of the given bandwidth each 50 milliseconds, which can be saved in a CSV file. It is also shown in three different speeds on a display.
  • “Receivers’ Pane” shows up to six combos of spectrum/spectrogram of the complete up to 24 parallel demodulators (they additionally can be shown in the Matrix, as in former versions).

See screenshot on at the top.

“Signal History” offers many applications, to name just three:

  • analyze fading and its structure with an unsurpassed time resolution of 50 ms
  • document fade-in and fade out
  • measure signal-to-noise ratio of signals

As an First Aid, I have written a PDF of 19 pages with 36 instructive Figures. There you find a step-by-step introduction plus numerous example on how to use this valuable tool in practice. Please download it here. (Another tab opens, where you have to double-click “SDR_COM_Marker” to start download.)

Surely, I will come back to these most welcomed features in more detail. For now only some screenshot examples regarding “Signal History”, which have been realized by analyzing the CSV files with QtiPlot:

With some statistics applied on the CSV file of Signal History, you’ll get a deep inisght into fading structures. Top: original data (black), averaged (yellow), median (read line). Bottom: box diagram, histogram, 3D-band. See following screenshots for some examples.

 

… and this is just the beginning! [Receiver: Elad FDM-S2 & AirSpy with SpyVerter]

Murmansk FAX: 6.328,5 kHz, new Frequency

Murmansk_6328k5_120_576_1kShift_20170609_0450

Tune into 6330,4 kHz LSB, to get the right black/white frequencies, centered at 1.900 Hz. Shift 1.000 Hz, so 1.400 Hz = white, 2.400 Hz = black. 120 RPM/576 IOC, no APT! Received on June 9th, 2017, at 04:50 UTC.

Reports of the death of Murmansk FAX had been slightly exaggerated … After having searched for it in vain in 1Q/17, it now popped up on 6.328,5 kHz from former 6.445,5 kHz with an irregular schedule, namely at 03:30 UTC at one day and 04:50 UTC another day.

Just fair quality of both, conditions and transmitter, made it very difficult  to read the text in the upper part of this weather chart in Cyrillic, with just: Прогноз … 21 час [Prognosis … 21 hour …]. Receiver AirSPy & SpyVerter, decoder Wavecom W-Code.

Also received on June 1st, 2017, but starting at 03:30 UTC – same area, first half of the transmission heavily distorted by an RTTY signal, see below:

Murmansk_6328k5_120_576_1kShift_20170501_0330

Reception on June 1st, 2017, from 03:30 UTC on 6.328,5 kHz.

Iceberg Prognosis has been received on scheduled 8.444,1 kHz at 20:00 UTC on June 8th, 2017; see below:

8444k1_Murmansk_20170608_2000

Murmansk FAX with Iceberg Prognosis  on 8.444,1 kHz at 20:00 UTC on June 8th, 2017. Cyrillic texts not quite readable. Also received on May, 31st, 2017, same frequency, same time.

Not a trace on/near also listed 7908,8 kHz. It seems that otherwise commendable NOAA publication Worldwide Marine Radiofacsimile Broadcast Schedules is outdated regarding this station.

PC-HFDL Display: Receive, decode and analyze the biggest net on HF!

HFDL is a net for data communications between airplanes and ground. The results can be shown on Google Earth . This screenshot shows a part of 29.000+ entries, received and processed on August 15th, 2016.

HFDL is a net for data communications between airplanes and ground. The results can be shown on Google Earth. This screenshot shows a part of 29.000+ entries, received and processed on August 15th, 2016.

 

Communications between air and ground is mostly done on VHF, UHF and SHF. But if an aircraft is out of reach of a ground station station due to the limited “radio horizon” of these bands, it has to maintain communications by either satellite or HF. This HFDL net is in fact the most massive professional user of HF right now. Within 24 hours, I get more than 40.000 live messages with a modest equipment.

With his software Display Launcher, Mike Simpson from Australia provides a most valuable tool to analyze up to nine channels in parallel. His software also draws positions and routes onto Google Earth. Mike has spent much energy on coping with many inconsistencies of transmitted data before it all really goes smoothly.

This free software is the vital part of a monitoring project to receive, demodulate and analyze live up to nine HFDL channels in parallel. Other ingredients you need is a software-defined radio (SDR), nine virtual audio cables (in fact, a piece of software) and a decoder software. Don’t forget an antenna and a PC …

This setup comprises a semi-professional monitoring station which will allow you to receive and track many of the nearly 3.000 airplanes using HFDL. This also covers the military, business jets, helicopters and some other delicate users. It maybe used as an important complement to Flightradar24’s web service, whenever their VHF/UHF/SHF-based net is out of range of the aircraft. This is particularly true over vast water masses like oceans and sparsely populated land masses. Furthermore, Flightradar24 erases some sensible flights from the raw material before publication on their website. This is clearly no “censorship”, but some thoughtfulness in regard to those countries where reception and publication of HFDL data is more tolerated than explicitly encouraged by the government.

In a 9-page PDF, I published a step-by-step recipe on how to set up such an HF monitoring station for up to nine parallel HFDL channel. You can download it here.

Wake up – ICAO Selcals

If you ever had an ear on the aero bands, you are already familiar with ICAO Selcalls. With this 2 x 2 tone signal lasting for about 2,2 seconds, a Ground Station alerts a specific airplane to open up for communications. The short video on top of this page shows a typical initial contact, where Ground an Air are testing the Selcal.

This paper (click this hyperlink) describes on three pages with nine illustrations, one video and one audio the procedure and gives some background information. These may improve correct decoding of the somewhat delicate signals, as it will show how to look up the Selcal and follow the flight. BTW: It is planned to extend the pool of 16 tones to 32 tones by September 1st, 2016.

P.S. Remember to save the PDF and open it with a recent version of Acrobat Reader. Otherwise the multimedia (video, audio) will not work!

20 MHz HF: “HackRF One” on Shortwave

world Kopie

The world is full of software-defined radio (SDR), but HackRF One has a rather unique position – thanks to its vast maximum bandwidth of 20 MHz. With an up-converter, this combination covers more than 70 percent of the whole HF range from 3 to 30 MHz. Even better: with proper software you can record and play this enormous band!

However, this stunning bandwidth is achieved by a moderate resolution of 8 bit, resulting in a dynamic range of just nearly 50 dB. Or the half of SDRs like Elad’s FDM-S2.

Anyway. I wanted to know in practice what you can actually do with such a set at a budget price plus mostly free software. The results surprised even me: Properly used, this combination convinced as a quite decent performer on HF! The world map above shows some of the stations received with the set (see insert bottom left) to test its performance.

I laid down my experiences and recommendations for best reception in a paper of 17 multi-media pages full of examples – including 55 screenshots, 21 audio clips and one video. The PDF shows how to optimize reception of broadcast, utility and amateur radio stations. It covers many examples on how to analyze recordings, to decode data transmission with free software plus live decoding of 14 channels in parallel. It also gives some examples of combining HF reception with the internet, e.g. regarding the reception of signals from airplanes (ARINC, HFDL) and vessels (GMDSS).

My experiences really left me enthusiastic about this set.

You may share this enthusiasm and download the PDF of 43 MB here. Save it on your hard disk or USB stick, and open it with a most recent Adobe Reader. Otherwise, the multimedia content will not work.
[Einen deutschsprachigen Test  habe ich jeweils als Titelgeschichte in der April- Ausgabe 2017 der Fachzeitschrift  Radio-Kurier – weltweit hören und in der Mai-Ausgabe der Fachzeitschrift Funktelegramm veröffentlicht.]

Aero: HFDL & flightradar24

The video shows how to combine some software to get and visualize more information from your HFDL monitoring.

HFDL is a data mode, intensively used between air and ground. You can receive these data and decode it with e.g. PC-HFDL software. These data maybe automatically streamed to software PC-HFDL-Display. It takes up to six sources and displays all information neatly in a spread-sheet style.

If you click on the Flight Number in the resulting spread-sheet, website flightradar24 opens up and shows the complete route of this flight, together with many other data.

Note, that not each and every Flight Number is listed on the flightradar24 page. This page relies mainly on position reports on the ADS-B network, transmitted on 1,090 GHz with a range of rarely more than 400 km. Out of this range, HFDL steps in. ADS-B plus HFDL is a charming combination as is the two software and the web service presented in the above video. Click HD button at bottom right there (“Enable HD Quality”) to get the best quality.

Multi-Channel Monitoring

Matrix_24_RDS

In recent posts, I already wrote about my experiences with Simon Brown’s software SDR Console V3.0. It matches most SDRs, delivers now up to 24 virtual receivers and is capable to run multi instances, i.e. you may run several SDRs on one PC in parallel.

That’s exactly what I did when I connected three SDRs FDM-S2 to a PC, running 35 different ARINC-635 channels in parallel resulting in 68.000 decoded messages. It worked brillantly.

And there is much more, e.g. recording and playing 24 audio channels from broadcasters throughout 20 MHz (the whole FM band!) with hardware RFHack One.

This paper provides a hands-on and step-by-step guide for some vital monitoring tasks like:

  • using up to three receivers on one antenna and one PC
  • working with multi instances of GUIs
  • working with multi instances of software decoders like PC-HFDL and MultiPSK
  • carefully planning a monitoring session
  • analyzing  the decoded results and apply some basic statistics on 68.000+ messages
  • record and play 24 channels incl. RDS data within a bandwidth of 20 MHz on the FM broadcast band plus on HF with RFHack One (see screenshot on top of this page, “Matrix” mode)
  • … and much more
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