Tag Archives: Propagation

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]

Play it again, HAARP

Alaskan station HAARP is re-activated for some scientific purposes in late February, 2017. I received them on 2.800 kHz as well as on 3.300 kHz with carriers showing their scheduled pattern. Alas, reception was too weak to make out any modulation. See screenshots below, containing all sufficient data like time, frequency, resolution etc. Reception has been done in Northern Germany with FDM-S2 by ELAD at a quadloop antenna of 20 m circumference.

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.

ASAPS: HF Prediction online & free!

Flight AF 128 from Paris to Beijing: What is they best time/frequency combination to communicate with Stockholm AOCC on HF?

Flight AF 128 from Paris to Beijing: What is the best time/frequency combination to communicate with Stockholm AOCC on HF en route?

 

HF prediction seems to be a somewhat neglected field among short wave listeners, as well as hams. At the same time, some knowledge of how propagation works on specific paths or into defined areas will greatly enhance your hunting success. If you have considered the somewhat flat learning curve of some software as an obstacle, there now is no excuse. With ASAPS’ recently even more improved online services, you are on the sunny side of HF right now.

I had written a short paper explaining how this free service can be used especially for Utility DXing. If you also ever wanted to know the relation of a waste paper basket and multi path propagation, please download this PDF (7 pages, 22 illustrations) here.

Rundfunkempfang auf Kurzwelle: Eine Einführung

Kleiner Streifzug-1

Nach wie vor sprechen internationale Rundfunksender noch mit einer starken Stimme auf Kurzwelle. Diese Einführung beschreibt auf 33 Seiten und mit 31 instruktiven Abbildungen sowie vielen integrierten Hörbeispielen, wie diese Kommunikation zwischen Sender und Hörer funktioniert. Anders als sonst, wird hier auch die Planung aufseiten der Sender berücksichtigt – und was wir Hörer davon haben.

Schon das opulente Cover (siehe oben; Dank an Christoph Ratzer, OE2CRM!) zeigt, dass in diesem Thema weiterhin jede Menge Musik steckt!

This 33-pager in German has been written as introduction into international broadcasting on shortwave. It covers frequency planning of the transmitters as well many aspects for us listeners. 31 illustrations and many sound example may make it digestible even for people who don’t speak German.

Perseus & Markers: Great Tools for analyzing Propagation!

Ionosphäre_CHU

The Perseus SDR comes with a software, where you may define up to eight markers. Each of them measures the level of the signal at distances of 100 ms to 5 seconds and writes it into a CSV file. This is the base for further analyzing these data, i.e. propagation. See such an analysis of the fade-out of CHU on 3.330 kHz on top of this page.

With an (active) antenna delivering a constant antenna factor over specific range – as all professional antennas do, e.g. RF-Systems’s DX-1 – you may also switch to logging the field strength of the signal in dBµV, rather than the input level in dBm.

The first paper presents a general introduction into this concept. It has been translated into English by Guy Atkins.

The second paper, in German, goes more into the depth of analyzing the data. But it’s 13 illustrations will make it under stable also to readers who don’t understand German.

Five Mongolians on Long wave

Mongolia_209_rays_2200

Since I visited Mongolia in 2001, I fell in love with this country. Hence, reception of all their radio stations on long wave caught my double interest. With some help of other listeners, I managed to receive all stations and analyzed their reception. Without any 100 g of Chinggis Khan Vodka, to which I surprisingly bumped into at Sarazul at Warnemünde in late summer 2015 …

Read this paper, to get also some information on how to receive and analyze stations which even might be too weak to hear.

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