I've been DXING and monitoring the HF bands for well over 45 years. I'm also a licensed amateur radio operator. I can identify many signal types on the HF bands but this one has me stumped.
I've been monitoring this strange "mystery" signal that slides up and down within frequency ranges. I first came across this signal back in November of 2014. It was continually moving up and then down in the 5.303 Mhz. to 5.498 Mhz. frequency range. This signal seems to begin around 0330UTC. When it reached the upper and lower limits of this frequency range, it would sit for a few seconds, then change its direction. This pattern always repeats. Lately I've noticed the frequency range seems to change a bit. I've heard it as low as 4.899 Mhz. and as high as 5.512 Mhz. This signal has no regards for any stations operating within these segments. For example RAF VOLMET is always active on 5.505 and this signal will move right through it.
I had been wondering if perhaps this signal was something local to me. I answered that question by going to the WEB SDR site and selected other controllable receivers world wide. I was able to hear it on most of them. This signal is best heard in USB or LSB modes.
I have spectrum and waterfall recordings of this signal along with a mp3 file. You can view these files along with others on my Shortwave MW DX blog here:
http://www.w2gjw.com.
If anyone has any idea what this may be, please leave a message on my site or respond here.
Thank you for your time and help in solving this mystery!
73-