A group of Portuguese amateur radio enthusiasts are spending their own vacation time trying to identify the location of a series of GPS buoy clusters that are transmitting, illegally and for years, on the 10 meter band.
“So far, we have had some success in determining the location of the few that we can receive when propagation allows. The data suggests that these clusters are located in the Atlantic, alongside the coasts of Africa and Europe but it´s possible that they are present elsewhere”, indicates Paulo Teixeira, CT2IWW.
According to Paulo´s description, these transmissions consist of three second long F1B bursts(RTTY) at 51bd, 300 kHz shift. Individual transmissions are 10 seconds apart with the whole process repeating every five minutes. Frequencies are between 28000kHz and 28120kHz, at 5 kHz intervals.
“So far we detected them on 28010, 28025, 28035, 28050, 28065, 28075 and 28101 khz but we believe that other frequency ranges are possible”, advances the team´s spokesman.
The group requests the assistance of the amateur community, particularly of those amateurs along the Atlantic, to look out for these transmissions and record them, since they are having a tough time getting more samples, due to lack of propagation.
“More recordings are needed in order to get greater consistency of the decoded data and, possibly, work on an automated or semi-automated decoding solution”, detailed Paulo, CT2IWW.
According to the group, it´s important that the recordings indicate the date, start time UTC, frequency and mode, preferably in USB. Audio center frequency between MARK and SPACE should be kept as close as possible to 1500Hz to achieve grater consistency (eg. 28025kHz should tuned at 28023.5kHz USB). Recordings should be, at least, 10 to 20 minutes long.
Results can be emailed directly to CT2IWW (email info on QRZ.COM) or, preferably, as a link to a cloud upload like Dropbox, Mega, etc.
https://www.youtube.com/watch?v=TgAkcmd7ixA Read more