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Another odd signal (or signal-like phenomenon)
Posted: Tue Oct 24, 2017 6:58 am
by elroy
This evening I was tuned in the area of the international broadcast band around 6 MHz. At one point, I saw what appeared to be a signal moving in frequency from low to high. In the tuning window, it appeared as a ripple moving from left to right across the frequencies. In the waterfall, it appears as a straight line angling upward from left to right, mostly on the lefthand side of the screen. Here is a screen shot showing that line:
Is this likely something internal to SDRplay? If it's a real external signal, what kind of transmission would this be?
Re: Another odd signal (or signal-like phenomenon)
Posted: Tue Oct 24, 2017 8:37 am
by vk3alb
It's probably a chirp used to measure ionospheric conditions.
Google "chirp sounder radio" to learn a bit more about them. As a traditional radio listener you'd just hear a quick squeak as it swept through the pass band.
The magic of SDR that you can see these things as well as hear them.
Re: Another odd signal (or signal-like phenomenon)
Posted: Tue Oct 24, 2017 10:47 am
by DanubeBCL
See for example
https://en.wikipedia.org/wiki/Ionosonde
Inososonde spurs will frequently appear daily on various SW bands on your spectrum/sonogram. Normal business on SW.
73, Heinrich
Re: Another odd signal (or signal-like phenomenon)
Posted: Tue Oct 24, 2017 11:31 am
by g1hbe
vk3alb wrote:
The magic of SDR that you can see these things as well as hear them.
Indeed. On a conventional receiver, you'd just hear a 'blip' as the signal passed through the passband, but on a waterfall you can see what it really happening.
You can also see all the image responses and other spurii of your receiver, which you would not know about on a normal radio!
Re: Another odd signal (or signal-like phenomenon)
Posted: Tue Oct 24, 2017 3:48 pm
by elroy
vk3alb wrote:It's probably a chirp used to measure ionospheric conditions. Google "chirp sounder radio" to learn a bit more about them. As a traditional radio listener you'd just hear a quick squeak as it swept through the pass band. The magic of SDR that you can see these things as well as hear them.
Thank you! Yes, the visual perspective provided by SDRplay and SDRUno provides a great way to learn about all kinds of signal phenomena.