Strong ringling on 24 Mhz at EA2/BI-044

Today Marcial EA2BDS and me have had a fine activation at the small summit at Galarregi. Easy hike at beautiful landscapes around Gernika. The propagation was quite good, with all the bands opened up to 28 Mhz. But, when I started on 24 Mhz, I found that the european stations, although very well copied (about 8-9 S), had also sometimes strong SP-LP “ringling”, making them unreadable! I’ve never heared back signals so strong…
Just as an example, I think this was an italian station calling CQ DX:

Have you noticed it?

73 de Mikel

Thank you for the audio document - that sounds like “round of the world” propagation.

These experiments were done by some stations in DL several years ago, and sometimes we could document as much as 3 or 4 circles around the globe. An audio document can be found here:

Obviously a very special propagation path has to be open for such effects to be possible at relatively low transmitter power. (ionospheric ducting, “Pedersen ray”) It truely is amazing!
Do you have any more audio files ?

73 Martin DF3MC

I was hearing something very like that from Barry M0IML on 10 metres a few days ago.

It’s not so common this Autumn DX season as last year. On numerous occasions 12m was nigh on unusable for CW due to the echoes and reverb. I heard it on 20m last week which really did surprise me.

A phenomenon sometimes known as one seventh of a second echo… the time it takes for the speed of light or the speed at which a radio signal travels through space around the planet


I would have thought it wouldn’t “exit” the Ionosphere into space but the reverberation is caused by two layers within the ionosphere reflecting the signal creating a delay effect observed from Earth.

There’s a difference between space and space and space.

One is what the Starship Enterprise travels through: Interstellar space.
One is what Philae travels through: Interplanetary space.
One is the space which surrounds our planet.

Does that help? :wink:

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Sure Andy, but I would have thought in theory HF < 30 MHz shouldn’t go through ANY type of space at all (ideally speaking). Hence all this ringing phenomenon would be created in the ionosphere only. Maybe some radio astronomers can chip in, fascinating stuff.

This is the head on clash between knowledge and wisdom.

Knowledge is knowing that the tomato is a fruit.
Wisdom is knowing not to put tomatoes in a fruit salad.

So, “space” doesn’t necessarily mean what you think it does.


Radio Astronomers? I think most would just complain about the ionosphere as that annoying stuff that can make their phases go a bit iffy!


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I know I keep telling my Mother to stop mixing the two together - what is a salad, but she still continues :wink: