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Mystery in Pac NW

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SCPD

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It started Monday-ish on approximately 13035Khz -- some kind of bad transmitter. I was thinking it might be one of the superDARN transmitter sites since it seems confined to the Pacific NW. I can hear the buzzing in Vancouver, BC and here in Seattle. Was not able to hear it in SoCal.

Here's a short video: http://home.comcast.net/~k7cj/weirdOTHR.wmv

Any ideas?
 

majoco

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I have the buzz noise but no gaps in between where you have noise bursts on 13035kHz, also on 12970 and faintly on 13001. The buzz seems to change character occasionally. Unfortunately I have packed up a lot of my gear in preparation for moving house so can't do any further analysis. 0500z on Christmas Day (Jeez, I'm a sick puppy!)
 

SCPD

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Martin, I've checked remote sites in Tokyo and Brisbane with no luck. I think it's local to the NW USA but I could be wrong. The signal drops out completely after dark so not sure if it's local or possible toward the Alaska region.
 

Token

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Nick, I have no real or firm ideas what it is, but I would think it is not a radar of any sort.

Notice it is asymmetrical. Symmetry is not a requirement for radar, naturally, but I just mean it looks like it has some unintentional stuff visible. Near 13045 kHz is some noise, but there is much more noise smeared a good bit more on the low side, in the 13010 to 13027 kHz area. And the shape of the primary envelope is odd also, itself asymmetrical.

Note the pip of near CW around 13037 kHz. There is some odd and variable shape to that pip, inconsistent with what might be needed for an OTHR.

Like I said, no idea what it is, and of course it is pretty hard to say for sure not a radar, especially from this narrow banded audio recording, but it does not seem like one to me. Would sure like to get hold of an I/Q recording to take apart, but I have not been able to detect this locally.

T!
 

SCPD

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Token it's live right now. You'd likely have to use the perseus remotes in the area to see it.

Roger on the little pip -- it's centered right around 16036.4 but it does seem to shift ever so slightly.

I do notice quite a few of those sounders/radars in the area. The narrow 5khz ones.
 

majoco

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The variable 'noise' is there again this morning 2130z on 13035 and 12975 both S5 and a weaker signal on 13001 say S3. Today it's accompanied with an intermittant but regular 'chuffing' noise about two 'chuffs' per second. I've been around the house with a portable and it's definitely external. On USB there is no sign of a carrier, on AM it's stronger of course, S9.
Unfortunately my leads, SDR and laptop are in the lockup and I can't get them until next Monday. I'm just using old faithful Kenwood R2000!
 

SCPD

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Token I went to several remote sites this afternoon and it may indeed be located in SoCal area. You might just be too close to it. Both SoCal remotes do not show the signal, but the Arizona station shows it quite well.

Now, the (2) north Canadian remotes show the signal very strong. That could just be their quiet locations.

For me locally, I notice the signal tends to fade in and out as if the antenna is rotating and/or varying the output power.
 

Token

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Token I went to several remote sites this afternoon and it may indeed be located in SoCal area. You might just be too close to it. Both SoCal remotes do not show the signal, but the Arizona station shows it quite well.

Now, the (2) north Canadian remotes show the signal very strong. That could just be their quiet locations.

For me locally, I notice the signal tends to fade in and out as if the antenna is rotating and/or varying the output power.
Nick, at ~2000 UTC the signal was S7 or better here locally, and I had a chance to take a good look at it. Still don’t know what it is, but more convinced than ever it is probably not a radar.

The pre-beep varies in length, I have seen everything from 0 to 35 millisec. Some pre-beeps are nice and steady, others sag or change freqs during the pre-beep. Some even have a little modulation on them. And the pre-beep freq moves around, not a great deal, but it does change.

The pre-beep is not anyplace near the center of the TX bandwidth.

The multiple tones during the transmission periods drift around a lot, even interpulse. For the first ~75 millisec the signal is unstable, and then it steadies out somewhat, never really getting stable.

Not sure if this whole thing is a sick transmitter or if it is meant to be this way.

By the way, I saw several power steps while I watched it, steps that could be beam steering and would support it being some kind of radar. However, the power steps also could have been the result of a broken transmitter, or if a data mode multiple nodes in the network. I am not talking fades, but honest steps in power.

T!
 
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