Thursday, 11 June 2009

Very odd "sinusoidal" sweep on 6990 kHz

Well, HF is a garden of endless sound varieties.

Now, what's this? Something out of order?

Recorded on 6990 USB, wide filter setinng, at approx. 2109 UTC, S5-S7 signal strength.


ivlad said...

Obvious! R2D2 transmitting! :)

Manolis said...

LOL! Indeed!

The peculiar thing is the sinusoidal form of the sweep (if you take a glance using a spectrogram software).


Poacher said...

Hello, Manolis!

2 variants - this is jummer signal, or voice coder - scrambler.


Maria said...

This is tunning of scrambler.

Sounds very impressive:)


If i may notice, the record is in mp3 and has so-so quality, overwise it would be possible to say presicely what scrambler is that.

Manolis said...


I can provide a better-quality .wav file if you wish.

I can send it to the email address of the site if you are interested.


linkz said...

here is what u heard i suppose

indeed a nice stuff

Manolis said...

Hello linkz,

Thanks for the very cool screenshots. BTW whoever does this is illegal since he intrudes the Amateur band hihihi!

Do you use a Perseus SDR? I'm interested on bying one and I don't know if it is agile for numbers work, I mean I love the wideband display but I wonder if it has the "fast feeling" a true radio has, e.g. quick tuning and switching between memories, etc.

Would you recommend it?


linkz said...

Hi Manolis

Yep i'm using a SDR perseus
the most wonderfull device i've ever own.

directly looking at spectrum, double clicking to choose the near frequency, mouse wheeling to fine adjustment...

modes directly identified before getting on the right freq, just by looking at how it shows in the waterfall

quickly find carriers, which most of the time (out of bc ranges) indicates the "warming tubes sequence" of number stations HIHI

btw, you can set 6 x 100 memories, not very user friendly (you have to scroll down manually the list, no scanning) but you can create your own log, or using for ex the Klingenfuss one log or other source.
So when you wheel down/up on waterfall, every kHz (or other step) log indicates what you can find on those freqs, depending of the time of day

you can also get a record of a entire range of frequencies (in one time) then playback (1 week or 1 year after..) the file & move up or down the central frequency, adjust bandwitdh filtering change mode etc.. you got everything that happens on that range , during the record session (max is 1,6Mhz) file grows very fast, Gigs on HD is necessary

Im using an old P-4 2.8GHz HT w/ 500Gigs HD, 1024 Mo Ram and it works fine.

don't hesitate! that device (or other SDR) really changes SWLing point of view

Best Regards

Anonymous said...

6990 khz was a known frequency for HAARP.