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!
As I was asked for a look onto my monitoring workbench, I decided to write it down. It’s not to show “the real stone”, but an invitation for discussing efficient workflows which State-of-the-Art technology has to offer.
This PDF of 13 pages contains 25 hopefully instructive illustrations to comprehend my approach to monitoring; or, in this case: Utility DXing. Part of this PDF is also a 2:50 video, showing how to stroll between aero channels and to decode ALE. This video is also placed on top of this page.
The paper explains in detail the advantages of leafing through recorded HF files using the technology of the “living sonogram”. It also discusses some efficient strategies of voice and data reception, eventually touching even documentation.
To make use of the video content, download it on your hard disk, save it and open it by the most recent version of your PDF reader. It works on a PC as well as on a Mac. You can download it here.
Part of the EXCEL list
“HF for the pros is stone-dead, isn’t it?” This rather verdict than question is often heard even by hams. If you are telling them how busy the bands really are (as they cannot read about that in their magazines), they are doubting: “But you need professional equipment plus decoding software, worth my Mercedes Benz?”, they are upset by the answer: “Absolutely bullshit. A software-defined radio at 500 US-$ plus some free software will produce thousands of logs!”
Still don’t believe that? Well, here is the first thousand, caught just in the first half of June, 2016. Received with an FDM-S2 receiver at a quadloop of 20 m of circumference. I mostly concentrated on fixed (rather than: mobile) stations and of modes which can be decoded with free software – if they are not even outright SSB or CW.
You can download this log: Logs_EXCEL from where it may easily be opened not only by EXCEL, but also e.g. free LibreOffice.
If I find time, even more logs from the same HF recordings will be added.
I am greatly indebted to the busy and resourceful friends of UDXF for their work, thanks.
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.]
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.
ELAD’s FDM-S2 provides the output of three different channels within a given HF bandwidth of up to nearly 5 MHz. Hence, you may decode these channels in parallel. ARINC’s reporting system of ground and airborne stations is an excellent candidate to show this feature.
This paper is a step-by-step introduction in how to set up the receiver, the virtual audio cables (VAC), decoder, documenting software and Google Earth to show the results on the globe.
You may then easily configure hard&soft for other applications, e.g. the monitoring of GMDSS channels with communications from ship and shore.
In the last time, I had been fascinated by Russian lady’s voices. First, I bumped into some very short, disciplined radio checks on the cis-Caucasian net on 5.568 kHz. I spent many hours until I got all identifications of these coded airports. Then I was absorbed by exotic destinations as Samarkand, Turkmenbashi, Vorkuta, Astana … onother frequencies. What a fascinating continent of DX! Read more