HFU HF Underground
Loggings => Other => Topic started by: radioreddz on December 25, 2012, 1733 UTC
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it's 12:30 pm here in maryland and been hearing off and on a playing of some digital tunes. no real rhyme or reason just a digital tune. some times it alternates to being 10 over then barely heard for about 3 minutes then back to 10 over strong signal. tunes seem to be in AM mode.
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That is inside the ham 30 meter band, and without a recording it is impossible to make a for sure ID, but almost certainly it is any one of a dozen ham digital modes. At a guess I would say maybe JT65 or WSPR would be likely candidates.
T!
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the same tunes are again on that frequency. 10.140.5 same cycle peaks at s9 for about 3 minutes then fades to just being able to read and seems to be in LSB mode.
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With tones unless you know the exact digital mode, and what to expect each tone frequency to be, you cannot tell if a signal is USB or LSB. In this case it is USB. The frequency is 10139 kHz, USB, and the mode is JT65 (WJST). The range of 10139 to 10141 kHz is recognized WSPR/JT65/WJST section of the band. This means you will find users anyplace from 10139 to 10141 kHz using this mode.
I am looking at that section of the band right now, I see at least 6 stations between 10139 and 10141 kHz as well as one user on a c/f of 10138.8 kHz.
The cycle you are hearing is the listen/talk cycle of stations. They transmit for a while and then listen for a while, in predetermined time windows.
Like I said, 30 meter ham band, digital modes, WSPR/JT65/WJST. You will hear it all day long.
Information here:
http://hflink.com/jt65/
http://en.wikipedia.org/wiki/WSJT_(Amateur_radio_software)
T!
(edit) typo road repair
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thanks for the info.