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Loggings => HF Beacons => Topic started by: mark-n-nut on April 25, 2016, 0318 UTC

Title: Ditter on 6939.4 ?
Post by: mark-n-nut on April 25, 2016, 0318 UTC

Have not heard this before, about 4 dits per second, on 6939.4.  First at at 0310 utc here in northern Utah.  Some QSB. Anyone else hearing this one?  Don't think it is anything local.

73

Title: Re: Ditter on 6939.4 ?
Post by: Teotwaki on April 25, 2016, 0326 UTC

I am hearing it right now with mild fading and peaks about 15 dB above the noise floor. On my waterfall display it does not look to be clean CW and might have some sort of modulation.

Good catch!

Jim

Title: Re: Ditter on 6939.4 ?
Post by: ChrisSmolinski on April 25, 2016, 1127 UTC

I checked my SDR recording around this time, and had Link-11. That's possibly what you were hearing, and if it was very weak, it could sound like a ditter.

Title: Re: Ditter on 6939.4 ?
Post by: Teotwaki on April 25, 2016, 1352 UTC

Hey Chris!

I searched for an image of a waterfall display for Link 11 and it pretty much matched except for spectrum width so maybe it was an idle signal with no data being sent. Some examples on YouTube were 3 KHz across but last night this signal was a few hertz across. I've run across Link-11 on UHF frequencies because I am near the ocean but this is probably the first time with positive ID for HF.

Thanks!

Title: Re: Ditter on 6939.4 ?
Post by: Teotwaki on April 25, 2016, 1540 UTC

I found an audio recording here:  http://www.nonstopsystems.com/radio/radio-sounds.html

If the data bursts were removed that might be about what I heard last night, mainly the "beeps" or "chirps".

This image of a waterfall display is zoomed in pretty well but does compare to the smaller display on my Elecraft. I should have captured a screen shot of it.

(http://www.sigidwiki.com/images/thumb/c/c1/11175_KHZ_Crop_Waterfall.png/150px-11175_KHZ_Crop_Waterfall.png)

At the time my display was a 2KHz span and the trace I had was barely a tenth of an inch on a 4" screen

Title: Re: Ditter on 6939.4 ?
Post by: mark-n-nut on April 25, 2016, 1732 UTC

Thanks Guys!  I think you have figured it out.  I suspected that at first but over the time I spent listening I never heard any intermitant data burst.  Its gone now here, but will keep an ear out for it!

73, Mark