Category Archives: Broadcast

SDR Console V3: New and indispensable Software

V3_Dimtsi

“Living Sonagram”: On the right window, you see a part of a 24 h recording at 6,1 MHz bandwidth (ca. 2 TB) with 1 line/second. Tagged is the sign on of Dimtsi Hafash which is received by the undocked “Receive” panel of V3’s GUI. At the bottom: signal strength on 7180 kHz over 24 hours reveals e.g. s/on, s/off and fade in.

Just a small note on a real real big event: Simon Brown, G4ELI, has published V3 of his indispensable SDR Console software on June 18th, 2018 – after three and a half years of heavy coding. Download it here and donate. Or vice versa.

V3 is a quite universal software for most SDRs on the market. For all, it provides the same graphical user interface (GUI) and the same functions (plus those specific to some devices).

All

DXer’s delight: On top the sonagram to visually catch signals (here: JDG from Diego Garcia; tagged). Bottom, from left to right: receive GUI for fine tuning, decoder W-Code showing “JDG”, below this “Playback” panel for controlling the recording (back/forward, e.g.), and on the right a database.

There are many unique functions and modules which will take DXing with SDRs to the next step. For now, let me mention just two of them:

  • 24 parallel demodulators within the SDR’s bandwidth – fully independent in e.g. mode, bandwidth and AGC to receive, record and decode 24 signals/channels in parallel.
  • a sophisticated File Analyser  which presents a recorded band as “living sonagram” – whre you see and click to a signal which then is played via the basic GUI
6pane

Up to six parallel demodulators can be seen on the main screen (from up to 24 possible).

 

1520

1520 kHz from 18:00 to 05:00 UTC (local SR/SS: 19:43/02:58 UTC) with 100 Hz bandwidth and 0,0031 Hz resolution (= +65 dB over 10 kHz!) reveals at least 27 stations and their offsets.

Each of these just two features mentioned will open new worlds for DXing and even serious professional monitoring. I will be happy to come back to some applications of V3 in more detail.

Thank you very much, Simon, for providing this excellent tool for free!

4800

4’800 kHz: First CNR1 with sign on at 20:15 UTC and fade out, then AIR Hyderabad with the same, but s/on around 00:06 UTC.

 

7435kHz

You may export levels over time on one frequency or level over frequencies at a given time. This graph visualizes the activity on 7435 kHz with 86’400 levels (on per second over 24 h). The data had been exported to QtiPlot for further investigation.

Airspy HF+: What you hear, is what you get

 

 

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It has been dubbed “game changer” and indeed, the Airspy HF+ is a completely other animal of software-defined radio, or SDR. Developed by Youssef Touil plus team and produced by ITEAD, it sells for just US-$ 199 right from factory at Shenzhen, China. This is considered the middle class of SDRs, starting with cheap USB sticks under 10 US-$ and scratching the mark of nearly US-$ 5.000 with Winradio’s WR-G39DDC. This one also marks the transition zone from what even an engaged hobbyist allows himself to spend to the truly professional receivers of e.g. Rohde & Schwarz and Plath. To make it clear: You may achieve professional results at each price tag, even from an RTL & its clones, as Carl Laufer’s excellent blog shows almost daily.

The Serious HF-DXers in mind

Airspy HF+ has been developed with the serious HF (shortwave) listener in mind. In this field it sets new standards regarding sensitivity, dynamic range and noise. Its stunning performance is achieved by a revolutionary approach and a careful layout of the hardware, housed in a sturdy metal case.

I don’t want to add another explanation of this concept (my test report will appear in 1Q/2018 in “Funkamateur“) but just offering the pure stuff. Some first twelve audio examples should give you a truly hands-on impression to answer the one and only question: How loud does this animal roar?
Therefore, I compared about 100 often vastly different situations on HF between Elad’s FDM-S2 (US-$ 525) and Airspy HF+. From this collection, I carefully selected some first twelve examples to cover the needs of the casual listener as well as the hard-core DXer.

All audio clips were recorded in parallel with a 20 m quad loop as antenna, feeding a professional 1:2 HF splitter by Heros. Software used was free SDR-Console V3 by Simon Brown – thanks.

Dare to make use of your own understanding

First, you read a description of the case, followed by a recording with FSM-S2 and then by Airspy HF+. Each of both examples has been recorded with exactly the same bandwidth, mode, AGC etc. which had been optimized for that situation. You must listen to these audio clips with headphones to scrutinize the mostly very small differences. Aim you ear towards fading, noise and intelligibility.
This is not a traditional test, where the master of ceremonies masticates the results for you. It’s for the truly demanding DXer, “to make use of your own understanding” (Kant, 1784). Just a hint: weak stations make the difference!

Fasten your Headphones: The Examples

The audio examples are roughly sorted from easy to difficult signals. They were made in the first week of December, 2017.

Radio Sultanate of Oman, Seeb/Oman
15.140 kHz, 100 kW, AM, 5.350 km, 14:10 UTC, strong/free channel, SAM, 10 kHz bandwidth. Keep an ear on noise and slight fading!

 

Xinjiang People Broadcasting Station, ÜrümqiChina
4.500 kHz, 50 kW, AM, 5.500 km, 14:24 UTC, fair to good/free channel, SAM, 9 kHz bandwidth.

 

Bangla Desh Betar, Savar/Bangladesh
4.750 kHz, 100 kW, AM, 7.300 km, 14:29 UTC, fair/free channel, SAM, 9 kHz bandwidth.

 

Xizang People’s Broadcasting Station, “Holy Tibet”, Lhasa/China
6.025 kHz, 100 kW, AM, 6.850 km, 16:00 UTC, fair/strong broadcaster 5 kHz up, ECSS-L, 2,8 kHz.

 

Bangkok VOLMET, Bangkok/Thailand
6.676 kHz, 10 kW, USB, 8.800 km, 16:10 UTC, fair/free channel, USB, 3 kHz bandwidth.

 

Gander VOLMET, Gander/Newfoundland Canada
10.051 kHz, 10 kW [?], USB, 4.400 km, 15:20 UTC, weak to fair at fade-in/free channel, USB, 2,8 kHz bandwidth.

 

Myanma Radio, Yangoon/Myanmar
5.985 kHz, 50 kW, AM, 8.250 km, 01:00 UTC, weak to fair/interference from upper channel, ECSS-L, 5,5 kHz bandwidth.

 

Radio Aparecida, Aparecida/Brazil
6.135 kHz, 10 kW, AM, 9.900 km, 00:30 UTC, fair/free channel, SAM, 3,5 kHz bandwidth.

 

Time Signal Station CHU, Barrhaven/Ontario Canada
3.330 kHz, 3 kW, USB with carrier, 5.900 km, 06:00 UTC, fair/fsome interference from digital station above, USB, 3 kHz bandwidth.

 

Time Signal Station BPM, Shaanxi/China
15.000 kHz, 20 kW, AM, 7.750 km, 09:00 UTC, weak/free channel, SAM, 5 kHz bandwidth. Occasionally echo from mixing short/long path, some CW echo (long path) is running into the next via short path.

 

China Radio International, Ürümqi/China
1.521 kHz, 500 kW, AM, 5.500 km, 13:00 UTC, weak at fade-in/free channel, SAM, 6 kHz bandwidth.

 

Auckland VOLMET, Auckland/New Zealand
6.679 kHz, 5 kW, USB, 25.800 km (long path!), 07:20 UTC, very weak/free channel, USB, 3,6 kHz bandwidth. Here headphones are a must!

 

 

Offset/SNR: Some Ideas for Medium Wave DXing

Offset_5

Offset-DXing “on the fly” shows four different stations (spectrogram) on one nominal channel, namely 801 kHz. The window is baout 30 Hz wide and shows the carrier on HF level.

Although I use Simon Brown’s excellent software SDR Console V3 for years, I only now discovered a feature, being most valuable for medium wave DX.

Nearly each medium wave channel is populated by a couple of stations which mostly have a slight difference from each other, called offset. This often is specific to specific stations. It even reveals stations too weak to be heard. Software V3 will show these carriers of HF level during normal listening, being live or from an HF recording.

Read MW-Notes, to get some information on “how-to” on 6 pages, with 12 screenshots. There you will find also a hint for a method with even much more resolution (but: not “on the fly”) plus some information on how to measure signal strength and estimate/calculate the SNR of speech/music, rather than that of just the carrier.

You have to distinguish between absolute and relative frequency accuracy; the first is best achieved with a GPS-disciplined oscillator, the letter the normal case.

P.S. I started with these things back in 1997 with an evaluation board from Motorola, followed by sound card & software on audio level (“Soundtechnology zeigt Signale: Sieh’, wie es klingt!”, funk magazine 6/1998), to be continued on HF level from 2006, first with RFSpace’s groundbreaking SDR-14. Three years later, I published a survey of each and every 9- and 10-kHz-channel on medium wave by this method. After Apple closed their web service, these pages had gone astray, and the information is now not up-to-date anymore. State-of-the-Art now is the method described in the paper.

Medium Wave: Ex oriente DX

Medium wave saison has started, and am I trying to make the best out of it. Conditions are fascinating different from day to day, and even from minute to minute. With mainly focusing on “East of Suez”, with some other in between, please find some 50+ audio logs below. Click “Read More” button at the end, to expand the list to full length.
I am very much indebted to Christoph, OE2CRM, who with his very special mixture of charme and nuisance more or less forced me to explore a bit more of this frequency range 😉 First of all, I was and still am attracted by his outstanding logs which had been held impossible in Mid-Europe in the last decades.
I am using an Elad FDM-S2 at a wire loop of 20 m circumference with Wellbrook’s Large Aperture Loop Amplifier ALA100LN plus 7th order elliptic low-pass filter (1,5 MHz) by Heros to avoid any spilling over from HF (mainly that of: Radio Romania International); software used V3 from Simon Brown.

BEL3_Fishery_FRS_1143kHz

Part of the QSL from “Fishery Radio Station” (Taiwan Chü Yuyeh Kuangpo Tientai), BEL3, 100 kW, 1143 kHz, received September 25, 2017, 19:00 UTC. 謝謝, Station Manager Jin Mey Ju!

1700 kHz USA-Florida  WJCC Radio Mega in French, Miami Springs, 10 kW, 10-OCT-2017, 02:00 UTC.  Several IDs (e.g. in French) of this multi-cultural broadcaster.

 

1584 kHz G  Punjab Radio, in Hindi/English, London, 2 kW, 15-AUG-2017, 20:00 UTC. ID.

 

1566 kHz KOR  HLAZ FEBC in Korean, Jeju, 250 kW, 26-SEP-2017, 17:00 UTC

 

1566 kHz HOL  Vahon Hindustani Radio in Hindi, Den Haag, 1 kW, 23-AUG-2017, 22:00 UTC. ID in Hindi.

 

1557 kHz TWN  RTI iLoveMusic in Chinese, Kouhu, 300 kW, 20-SEP-2017, 16:55 UTC.

 

1550 kHz ALG  Saharawi Arab Democratic Republic National Radio in Arabic, Tindouf, 50 kW, 27-SEP-2017, 21:01 UTC. ID: “RASD punto [?] info …” & in Arabic

Read more

2,5+ million of Field Strength Data from ITU

Tehran-Norddeich_1983-1989_15K1MHz_3D1

Seven years of hourly field strength data of a transmitter in Tehran/Iran, received at Norddeich/Northern Germany. You clearly see the influence of time, day, season and solar activity.

 

The International Telecommunications Union recently published many information for free, which had been locked for years behind an often impressive cash house or had been available just for a few blessed.

Among these information is a bonanza of 2,5+ million of normalized field strength data from the years 1969 to 1993. This time covers two solar cycles and by far doesn’t provide insights of only historical interest: You e.g. may visualize some circuits to see the influence of day, time and solar activity at a glance. And you may use this data to analyze some dependence between field strength and solar/geomagnetic activity.

As these data so far hasn’t attracted any interest of ham radio magazines, we are just at the beginning to make use of it. Join in!

The diagram at the top has been made with QtiPlot software. The same software has been used to visualize solar and geomagnetic WDC data, obtained from GFZ Potsdam – see diagram at the bottom.

Kp_vs-Flux_2

Solar flux (F10,7) vs. geomagnetic activity (Kp index), 1969-1993.

 

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]

AirSpy: How to listen to DAB+ Broadcast

It’s pure fun to listen to N-Joy, a North-German broadcaster, in DAB+. This digital mode should replace all classical FM broadcast, and has already done this in some countries where others offer both – like Germany.

DAB+ takes place in former TV bands. Several stations are bundled in a bouqet. In Germany, one usually is in comfortable reach of at least one of these bunches, see footprint on a map, with stations around my location:

map

Footprint of DAB+ broadcasts in Germany. Pin = my location. In the list you see the stations plus the channel (“bouquet”), here 5C omnidirectional from Hannover with 10 kW and 6C, also from Hannover, but pointed to the east, with 8 kW.

As AirSpy is covering also these frequencies with high sensitivity and a decent dynamic range, I gave it a try.

First software used is called Welle (English: wave) by a team around Albrecht Lohofener. I use it on a PC/W10. It’s easy to install, and then start it by the usual double-click. An MS-DOS windows opens, starting a routine for searching and opening the AirsSpy connected to your PC. This window informs you on all steps the software is doing.

Then the graphical user interface starts. First you have to scan the bands: click “Sendersuchlauf -> Start” (the software detects on what country code your OS is running and switches automatically to e.g. English), see screenshot:

Welle

The scan is running, 13 stations have been found so far. With expert mode (“Expertenmodus”) activated, you see the spectrum of the frequncy set being scanned.

From the spectrum (right), you might see if HF gain ius ok, or that you should go from automatic (“Auto HF-Verstärkung”) to manual gain control (“Manuelle Versätrkung”) to either imporve sensitivity or to avoid distortion due to strong transmitters nearby. With me, “Auto” drives fine.

After finishing the scan, “Welle”  comes down with the bouquets in reach:

Sputnik

Just click your station from the list on the left, and the station will be heard. Many of them provice additonal information, as here MDR Sputnik with weather. On the right you again see the spectrum of the whole bouquet (6B, 183,648 MHz) plus additional information an the quality.

Secondly, a more technical approach is offered by Jan van Katwijk with also free Qt-DAB. I also use it on my PC/W10. After downloading the suite, containing also other intersting software, just start “qt-dab-0.999”. An MS-DOS windows opens, followed after some seconds by the GUI. Here you have to define the receiver from a drop-down list, choose the boquet (5C, in this case), and scanning serves you the stations’ list. You may have up to five different windows open – from the MS-DOS window to more detailed technical data, including a QPSK phase window, right from the spectrum.

QT_2

Qt-DAB presents you with up to five windows: MS-DOS on top; gain control main window and technical data below, and spectrum plus QPSK phase constellation at the bottom. “Klassik Radio” on 173,352 MHz playing Bach: “What God does that is done well”. Not to talk of what the authors of the DAB software had done …

Thanks to both, Albrecht and Jan, to have developed this fine piece to software, free of charge!

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