August 06, 2007

D44TD audio recording of G4LOH

The tests last evening were received on WSJT and recorded. This is the file received at 20:11.30:

0-26 seconds G4LOH received at D44TD 144290.7MHz

26-52seconds G4LOH received at D44TD 144290.7MHz

I believe this is a 25 second burst. It may be a meteor or a high altitude aircraft. It is not clear how far the duct extended from D4 but there was no duct evident from IO70 to the South West at the time.

Split into two parts due to limitation of Moveable Type Blogging software.

I was sending a beacon signal with the CW keyer set to slowest holding both paddles to send a di dah di dah di dah with a "di dah" sequence taking approx one second.

Given that the recording is in 2.3KHz it would have been about 539 in a narrow CW filter. The tone appears to be very close to the expected 700Hz. (edited. DL4YHF says the tone is 820Hz which fits with my experience that the radio at D44TD is approx. 120Hz LF)

I have started looking at the file with DL4YHF's audio analyser and I am more and more convinced this is my transmission.

Apparently there is another burst, shorter and louder also on the HDD with Norbert.

Anyone who can provide audio analysis to really bring out the keying and maybe look for signs of doppler would be most welcome.

This event makes 4 consecutive days in which signals have been received over the 4000km path, most likely by the tropo + ms combination mode.

I would like to offer my sincere thanks to DL8YHR and DL8LAQ (the team at D44TD) who have been largely without sleep for many days now and yet never hesitate to give more of their time to this fascinating project.

I hope many others will now explore DX beyond the "normal" 2500km limit and that the DX records we have set are short lived by your efforts.

I made this picture with Spectrogram 15:

Waterfall analysis G4LOH at D44TD 5 8 2007 20 11 UTC.jpg

It appears to show a linear doppler shift from 865Hz to 807Hz over 34 seconds. My guess is that this was an aircraft over the Bay of Biscay enabling my signal to access the extensive duct North from D4.

Update 17:44
I listened carefully to this playing it through Spectran, setting the bandwidth filter to about 30Hz (you have to be cute with the left and right mouse clicks to track the doppler) but the da di da di da seems very clear when listening like this. No way 539 like I guessed before though!...about 319-419 at best!

20:05 UTC

Tried sked again with D4 since 18:30 nothing heard at all today.

Posted by Tim at August 6, 2007 12:47 PM


73's Derek

Posted by: Derek Hilleard at August 9, 2007 12:00 AM

Hi Tim,

tnx for blog entry. I will send you missing files asap. Frank needs some time to get all the equipment back to place it belongs.

73, Norbert - written on a new MacBookPro :-)

Posted by: Norbert at August 9, 2007 07:22 PM