As long as this modulation is moving, you can sometimes see it on other bands as well, special on 20m, je to OTH-radar (Over The Horizont), it's still the biggest piece of crap on shortwave. It makes hearing and operation completely impossible. These radars are almost in all countries…
Pleasant listening
Ivan
low power

@OM7CM wrote:

Hi, where the modulation display program can be downloaded ? 🙄

Hi, for example HERE:

http://www.qsl.net/dl4yhf/spectra1.html

or HERE:

http://sdr-radio.com/

73! I had a little Kenwood hand with me, OM5NA

So then what is it???? “some” type of modulation???, I mean, that it is still OTH, (at Funkamateur 11/2011 a 12/2011).
you 73
Ivan

ivan wrote:
As long as this modulation is moving, you can sometimes see it on other bands as well, special on 20m, je to OTH-radar (Over The Horizont), it's still the biggest piece of crap on shortwave. It makes hearing and operation completely impossible. These radars are almost in all countries…
Pleasant listening
Ivan
low power

spectrum in the picture, I dare say, rather it shows some kind of OFDM modulation. It is definitely not a sonogram of an OTH signal…

On the side of the monitoring system of the International Radio Amateur Union (IARU) sound recordings of various types of unwanted interference in the amateur radio band are available. There is also a paragraph, which deals with the issue of horizontal radars.

http://www.iarums-r1.org/iarums/sound/main.html

YOU 73! I had a little Kenwood hand with me, OM5NA

@janop wrote:

Here's a snack: http://eyers.sk/ham/cotoje.mp3

OK, so we have an audio recording. What next … ❓

Unfortunately, the recording is overmodulated, distorted and, moreover, made in a format with lossy compression, which caused distortion and irreversible loss of the ability to detect certain signal parameters. 🙁

However, the fact is important, and that's what it's all about, that it is definitely not OTH, but 12-channel phase-modulated operation with a pilot signal. According to the IARU monitoring system, this is a professional eastbound service.

I have attached a picture to better illustrate the process of processing the recording, on which it can be seen:

1. The original distorted recording,
2. The useful part after trimming the parasitic signals,
3. The result of applying the autocorrelation function,
4. The resulting rough phase characteristic.

So that we can also partially close the issue of OTH in the 80m band, so most often we can register them in the mode of operation shown in the picture, where in 6 visible in the second window 7 pulse clusters (burstov) wide approx 40 kHz changing frequency (in the picture in the diagonal) po cca. 750ms. During a normal QSO, you will not even register this phenomenon with a stronger signal from the opposing station.

And finally, a few more thoughts on creating audio recordings …

If you create recordings only for your own archive, it doesn't matter what format you prefer.

However, if you want to make a record for further processing or analysis, it is necessary to follow certain generally known principles:

1. As I already mentioned, the audio recording should be created in an uncompressed form (wav, aiff) without any additional intervention (post production). Forget about recording through a microphone or mobile phone…

2. The recording should be made via a recording cord or a virtual audio cable (VAC). However, pay attention to the volume level when recording. The maximum signal level during recording should not exceed half of the possible maximum, which guarantees a certain margin for unexpected situations.

3. The preferred audio format should have a minimum bit depth 16 bits when sampling 11025 kHz (12000 kHz when using Winrad programs, HDSDR, etc…). This sampling is sufficient to produce a sound (but not IF or RF) recording of normal operations in the KV band.

73! I had a little Kenwood hand with me, OM5NA

@janop wrote:

OM5NA,
thank you for the exhaustive analysis. I have the recording saved in flood format for Winrad. I created an excerpt from the recording by starting winrad and in the background started recording through the mixer in windows.
I did not do normalization, but I set the signal level in winrad roughly according to hearing. I saved it in mp3 format of any size.

But you also achieved very good results with this replacement.
I can know what programs you used for the analysis?

Listener OM3-0233, Jano

Hello Jano and greetings to the team,

I also used Winrad for a while, but after starting the Winrad HD later HDSDR project, I remained faithful to this program. The WRplus program proved to be useful for VKV/UKV, which, among other things, can also decode RDS.

If you are installing HDSDR, so open the file with it, which you made in “the old one” Winrade and select the option to save recordings in AF (Audio format). In addition to AF, it is also possible to save the file in IF or RF format. Activate file playback, select USB mode, set the filter match to approx 4 kHz and press the record button, set AVC appropriately. The selected operation is then saved in the predefined folder in the required quality and format.

Pre “offline” I used the paid version of the program for the analysis “TO” (Signals Analyser). However, its freely available version is also available for normal use.

A couple of possibly useful links + description:

Signals Analyzer – the program is designed for detailed analysis of various signals. The main area of ​​use is the analysis of unknowns, disturbed, complex signals…
http://signals-analysis.blogspot.com/

You are asking demo version of SA is to master the basics for working with the full version of the program. It has limited options, and some functions are blocked.
http://signals.radioscanner.ru/info/files/item1/sa_free.rar

SDR-RADIO.com is a console in the OS Windows environment for SDR reception and transmission. It is designed for commercial use, government and radio amateur use. The program provides an executive interface for all users of SDR receivers.
http://sdr-radio.com/

HDSDR is a freeware working in OS Windows. The program is used in radio astronomy, among the listeners (SWL), “hunters” non-directional radio beacons (NDB) as a spectrum analyzer.
http://www.hdsdr.de/

WRplus SDR – A Software Defined Radio program derived from the base code of Winrad, written by Alberto di Bene I2PHD
http://www.wrplus.altervista.org/

Spectrum Lab – Spectral analyzer with the possibility to display the screen “waterfall” (sonogram) enables realistic processing of sound signals.
http://www.qsl.net/dl4yhf/spectra1.html

And finally, a couple of pictures from the environment of various utility programs for SDR receivers in my photo album
http://om5na.rajce.idnes.cz/Experimenty_s_SDR_prijimacom/

YOU 73! I had a little Kenwood hand with me, OM5NA 8)