7.040 Digital Signal?

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  • Updated 1 year ago
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I've noticed, recently, that there is some sort of digital signal on 7.040.  It seems to be going away at night.

I'm curious if anyone else is hearing this.  If not I may have some sort of local issue, or possibly a device in the house or shack causing the signal.

If anyone could confirm they are hearing it I would appreciate it.


Rich - N5ZC
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Rich - N5ZC

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Posted 1 year ago

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Photo of Mike  W1BFA in Maine

Mike W1BFA in Maine

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I can hear it here in Maine at about an S5 with QSB, if it's the same one.  It starts and stops and is  modulated but I don't recognize it.
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Mark - WS7M

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There is one of those mail digital services (WinLink?) on about 7.030.  It puts up a wide digital signal at times for me.  
Photo of K3ZJ - Dave

K3ZJ - Dave

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One possibility is to try to match one of the patterns here:http://www.arrl.org/sounds-of-rfi
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Bob- W5TX

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I have heard this signal (very loud) and it appeared to have a time modulation, one pulse every second. Others have told me that it seems to come from South (they were in N Central U.S.) which may explain the strength here in TX. Modulation disappeared during the NAQP contest on 1/13 local with the signal disappearing completely at around 7pm local.
Hmmm, very strange.
Bob W5TX
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Rich - N5ZC

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Glad I'm not the only one hearing it.  That at least rules out a local man made source.

Guess we'll just have to deal with it.

Rich - N5ZC
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Tim Ellam

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A good source for information on in band unwanted signals is the IARU Monitoring System coordinated by DK9OM and HB9CET . The IARU R1 website has a link to the MS Newsletters and although R1 focused, there is good information for North America http://www.iaru-r1.org/index.php/monitoring-system-iarums

I note there is reference to a uncoordinated beacon at 7040.


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Don, VE2HJ

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These are WSPR signals. In the WSJT-X suite choose WSPR .Select the 40m frequency .


De Donald, VE2HJ

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Rich - N5ZC

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Thanks Donald,

I fired up WSJT-X and chose WSPR.  Sure enough, the signals were decoded.

I had never tried WSPR, so I had no idea what to listen for.

Rich - N5ZC
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Yes! it is always there here in California where I live. 7.040, always pretty strong.
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Bob- W5TX

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don't believe this is a WSPR signal.  Sounds like WWV except no voice and is very wide on ticks.
If it's a beacon it's very strange.  Spectrum was one second pulses.

Bob w5tx
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Stan - VA7NF

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WinLink HF hubs are common on 40M.  They idle with short (<1 second) bursts and read/write data when another station answers.