Another odd signal (or signal-like phenomenon)

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elroy
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Joined: Fri Oct 20, 2017 3:46 am

Another odd signal (or signal-like phenomenon)

Post by elroy » Tue Oct 24, 2017 6:58 am

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:

Image

Is this likely something internal to SDRplay? If it's a real external signal, what kind of transmission would this be?

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vk3alb
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Re: Another odd signal (or signal-like phenomenon)

Post by vk3alb » Tue Oct 24, 2017 8:37 am

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.

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Lou
VK3ALB

DanubeBCL
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Re: Another odd signal (or signal-like phenomenon)

Post by DanubeBCL » Tue Oct 24, 2017 10:47 am

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

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g1hbe
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Re: Another odd signal (or signal-like phenomenon)

Post by g1hbe » Tue Oct 24, 2017 11:31 am

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!

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Andy

elroy
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Re: Another odd signal (or signal-like phenomenon)

Post by elroy » Tue Oct 24, 2017 3:48 pm

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.
DanubeBCL wrote: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.
Thank you! Yes, the visual perspective provided by SDRplay and SDRUno provides a great way to learn about all kinds of signal phenomena.

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