HFU HF Underground

Loggings => HF Mystery Signals => Topic started by: Monophonia on August 04, 2022, 1359 UTC

Title: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Monophonia on August 04, 2022, 1359 UTC

A very wide discernable signal on the waterfall, with "carriers" every 4Khz.
First carrier at 3760KHz last carrier at 5192Khz
13:46UTC 8/4/22 ongoing
Bursts up to 18 seconds long, some as short as 2 seconds long, the transmissions are occurring no more than 20 seconds apart.

I have a recording taken in IQ mode centered on the first carrier, some screenshots of the waterfall showing the definition of the signal.

Receiver is my own KIWI SDR and 160M inverted V in Ohio.

(https://i.imgur.com/eEG08aE.png)
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Monophonia on February 10, 2023, 2153 UTC
Bumping this since It's still on my mind, and it's still persistent in the same spot with the same intervals.

Best observed to my knowledge on this kiwi: http://nd8dkiwi.ddns.net/
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Shortwave_Listener on February 10, 2023, 2344 UTC
That is really bad local RFI (interference).
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Monophonia on February 28, 2023, 1634 UTC
That is really bad local RFI (interference).

Well, I was able to verify that whatever it is, it's not local. We had an area power outage and it is as strong as ever using the IC-705.

When I get my noise flag from DXE I'll see if I can take a direction on it.
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Shortwave_Listener on February 28, 2023, 2023 UTC
That is really bad local RFI (interference).

Well, I was able to verify that whatever it is, it's not local. We had an area power outage and it is as strong as ever using the IC-705.

When I get my noise flag from DXE I'll see if I can take a direction on it.

A power outage doesn’t always eliminate local QRM. For example, it could be a device in a home with a generator.
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Monophonia on March 01, 2023, 1643 UTC
That is really bad local RFI (interference).

Well, I was able to verify that whatever it is, it's not local. We had an area power outage and it is as strong as ever using the IC-705.

When I get my noise flag from DXE I'll see if I can take a direction on it.

A power outage doesn’t always eliminate local QRM. For example, it could be a device in a home with a generator.

I don't think I defined local well enough, in this case myself and the immediate neighbors (300 yard radius). Nobody in that radius has an automatic standby generator so there is a fairly reliable period of outage before everyone hauls out their portables. And since it was mid-day with many at work, I don't think anybody actually started their sets.

I've done a fair bit of RFI hunting, this one just still has too many signal qualities for me to write it off as noise just yet hence the inquiry. Though reality often points to the boring answer.
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Shortwave_Listener on March 01, 2023, 1655 UTC
Have you checked any other nearby KiwiSDRs? If it is something that is not local it should be observable on another KiwiSDR in your general region.
Title: Re: HF UNID, 4476KHz center, 1432khz BW from 3760 to 5192KHz, 4khz carrier spacing
Post by: Monophonia on March 03, 2023, 1959 UTC
The nearest public Kiwi is swamped in it's own broadband QRM in that bit of spectrum.

 The rest of the mapped kiwis are 60+ miles away, no discernable signal on them.

I did get a bearing on it with my flag antenna, The strong null points off into empty field, by the map the nearest structure is over half a mile away. If the weather clears and I get the farm chores done I'll do a bit of driving and see if I can get additional bearings.