説明:
Unidentified Radar Jamming on 7MHz
We have suffered the damage of this unidentified noise and we are in trouble very much. This noise comes here about four or five days per week. We can hear it from 4PM to next day 8AM. It is impossible for us to receive weak DX signal on 40m band. This is a severe trouble for us. This noise has been coming since Spring of 2005. You can see the noise situation by this video
http://jp.youtube.com/watch?v=AthoPqyWy_MIn this Video, You can see the S meter changes while I turn my 40m 4element yagi. I also recorded the noise by changing RX frequency.
The noise masked for 6970KHz to 7035KHz at 19:46jst(10:46utc) on April 24, 2008. We have to give up QSO for Caribbean Sea and East coast station on CW. The width of this noise is about 65 to 70 KHz. Depending on the day or time, the center frequency of this noise shifted up and down. We often have the other pattern which masked for 7025 to 7090 KHz.
I looked for the source direction by 4element yagi. It seems to be the direction from Tokyo to 230-250deg.
I would like to have your information about this noise.
Best regards
Hisato JA1DOT
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