Category Archives: Utility_DX

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 It seems that otherwise commendable NOAA publication Worldwide Marine Radiofacsimile Broadcast Schedules is outdated regarding this station.

iZotope RX6 – A Miracle in restoring Audio

If you still desparately looking for a software to restore your recorded DX audio clips, iZotope’s RX6 offers an alomost perfect solution. While the de-crackling tool automatically removes all of these annoying statics, the near-unbelievable tool “Spectral de-noise” is doing wonders in extracting e.g. formants of speech out of noise, thus greatly enhancing intelligibility.

I did a convincing test with a clip of CKZN, New Foundland’s shortwave station still transmitting on 6.170 kHz with 1 kW; received June 1st, 2017 at around 02:00 UTC. The original recording is heard like this:

It looks like this, when opened in RX6, with spectrogram in the background:

CKZN_1

First step was to automatically get rid of most of the static by “de-crackling”. RX6 offers you the chance to see also the garbage, e.g. what has been subtracted from the signal, see screenshot below with a focus on the identified crackles:

CKZN_6_2

After this first step, the audio sounds like this:

Second step is the tool “Spectral D-noise”. Most comfortable is the “adpative mode”, where you see the audio much more clearly than in the original recording:

CKZN_6_denoise

And that’s the way, it sounds, with 12 dB attenuation of noise (default):

Another mode is the “learning mode”, where you teach the software what it has to consider as noise in the recording, and then clean it up. First, I did it with the strongest value of 40 dB reduction:

Sounds quite artifical – but drop your ear onto the last part, how clean the jingle sounds!

With some right, default is 12 dB, listen here:

This may be reduced to even 6 dB – you have to find the right balance by yourself:

To restore audio of DX MP3 clips, is not where this software is really adressed to. But even for this purpose, it’s strong algorithms perform better than any other device/software, I’ve seen in the last 50 years. And there are a lot more functions to tweak a signal further. Not really cheap, but unique. There’s simply nothing better!

 

Steckt sie alle in die Tasche: Reuters “Pocket”

Reuter_Pocket

Burkhard Reuter mit seinem “Pocket”: Eine Entwicklung, auf die er stolz sein kann

Wo eigentlich bleiben die Weltempfänger? Die Spitzenklasse kommt heute nicht aus Japan und schon gar nicht mehr aus den USA oder aus Fürth, sondern aus: Dessau. Dort hat Burkhard Reuter unter anderem seinen Pocket entwickelt. Das ist ein Taschenempfänger, den es auch mit Sendeteil gibt. Seine Leistung ist absolute Spitzenklasse. Sein Konzept folgt einem ab initio selbst entwickelten und “Spectrum Based Signal Processing” genannten Algorithmus. Alles an diesem Gerät ist schlichtweg außergewöhnlich: von der Leistung über die Wertigkeit bis zum Preis. Für die Titelgeschichte der Mai-Ausgabe 2017 der Fachzeitschrift FUNKAMATEUR habe ich Burkhard Reuter in seiner Werkstatt besucht, mir seinen Weg und sein Konzept erläutern lassen sowie seinen Receiver auf Herz und Nieren getestet.

Where have all the world band radios gone? The most recent one – and probably the best ever produced – emerged out of the workshop of Burkhard Reuter (pictured above) from Dessau/Germany, the city of Bauhaus fame. For the cover story (May, 2017) of the German FUNKAMATEUR magazine, I visited him and did an in-depth test of this smart receiver, following his unique “Spectrum Based Signal Processing” algorithm. His Pocket turned out to surpass reception quality of each and every world band radio before, scratching the performance of even professional table top receivers. Some versions of it also include a ham radio transmitter (QRP). Already another modern classics from the Bauhaus city …

 

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.

Decoding the whole DGPS band

This screenshot shows the automatically visualized result of a 15 hours’ session receiving the DGPS band, March 11th/12th, 2017. You clearly see the propagation effect during night (marked yellow).

For years, Chris Smolinski of Black Cat Systems offers a fine selection of Mac software, among them many pieces for hams and shortwave listeners.

He now presented an unique software dubbed Amalgamated DGPS which decodes, analyzes and visualizes all DGPS stations on long wave at once. This is done from an I/Q wav file of e.g. Perseus SDR. DGPS stand for “Differential Global Positioning System” and is a system of long wave transmitters in the range of 283,5 to 324,5 kHz transmitting FSK data in 100 and 200 Baud to correct for GPS signals. Look here for a short introduction to this topic.

[Einen deutschsprachigen Test der aktualisierten Software habe ich in der April- Ausgabe 2017 der Fachzeitschrift FUNKAMATEUR veröffentlicht.]

These transmitters are of regional coverage, like non-directional beacons, or NDB, in the same band. This makes them interesting for DXing and propagation studies as well.

All you have to do is to let the software analyze your I/Q files of a receiving sessions. Yes, it is automatically “chaining” your files. You then get a detailed list of decoded stations with some additional data. You also can visualize these data, as I did in the screenshot at the top. This is based on a 15 hours’ session resulting in 56 wav files of 675 MB each.

The software runs on both, Mac/iOS and Windows. On both systems it works fine, covering .0 and .5 kHz channels as well as both baud rates.

Here you see the complete list of stations and the number of their receptions. “Amalgamated DGPS” has decoded 516.918 logs in roughly 15 hours!

 

PropLab 3.1: How Propagation really works

 

Fergana_DK8OK_3DRayTracing

The software’s unique feature is 3D raytracing, showing an anatomy of propagation (see text).

HF propagation software seems to be full of mysteries. But its all about modeling physics. There are several models around, the most prominent surely is VOACAP, followed by ASAPS. VOACAP comes in very many different tastes like e.g. PropMan 2000 or ACE. It often has been coined to be the “Gold Standard” among hams and professionals as well. VOACAP gives reliable results on a statistical base for a month, whereas ASAPS returns propagation based on the current conditions of a day. It also gives propagation for an aircraft en route during its flight and takes at least a bit care of multi-path propagation which may degrade digital modes. Both work offline as online, and they are fast.

[Einen ausführlichen deutschsprachigen Test mit vielen Screenshots und Beispielen habe ich in der Januar- Ausgabe 2017 der Fachzeitschrift FUNKAMATEUR veröffentlicht.]

PropLab is giving you a much smarter view on what is really happening on a specific day and time at a specific path or area. It relies on the International Reference Ionosphere (IRI 2007) and uses the ray tracing technique. In short, PropLab is automatically fetching all relevant space weather data (not just sunspots) from scientific sources of the internet to model the ionosphere with its different “layers”.

You then give in your path, antenna etc. in a well-supported way. After having started “ray tracing”, PropLab lets refract rays at exactly this ionosphere with its high granularity and some real-world effect like tilts of layers which will result in e.g. propagation off the great circle. It will also beautifully show effects like focusing and gray line propagation, including Pedersen’s long ranging ray with time resolution up to one second – rather than one hour as that of VOACAP.

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