Unknown "Hypnotoad" Signals Spotted on HF

[Antenna101]

THREAD WAS MOVED FROM MYSTERIOUS SIGNALS.

Last update of the frequency list: 9th September 2025 23:50 CEST | 21:50 UTC

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Frequencies: 5247, 5251, 5315, 5530, 5575, 6020, 6620, 6665, 6370, 6380, 6700, 6878, 7060, 7150, 7515, 7353, 7396, 7753.5, 7920, 8110, 8270, 8188.5, 8380, 8800, 8920, 8998.5, 9150, 9413, 9695, 9920, 15945
Unconfirmed Frequencies: NONE
Possible Hypnotoad: NONE
Good evening HFUnderground, I have been scanning the HF spectrum for the past week and an odd signal has caught my attention on multiple frequencies, thinking it's just interference: I looked into it from different listening spots and even KiwiSDR's so there I find out that this continously buzzing signal is indeed, not RFI. Here are my logs for the past week.

31st August 2025

A scan from today at 19:33:06 CEST displayed a DPRK modem on 5352 kHz and a new hypnotoad frequency on 6448 kHz. An israeli navy hybrid modem on 6619 kHz, 2G ale comms on 6885 kHz and possibly a morse station next to it by 2-3 kHz.

A powerful hypnotoad on 7353 kHz (as known previously, S7 signal).

Hypnotoad's new frequency was also spotted on 7515 kHz. A weak signal was detected on 8587 kHz and 8565 kHz looking like the hypnotoad, but whether it is, I am not certain and will have to look into it. A powerful but yet distorted signal was also spotted on 9255 kHz, I did not manage to get a proper capture of this signal on the scan but the waveform looks oddly familiar to the one of a hypnotoad signal, this frequency will be also looked into. 9655 will be also looked into

Out of the suspected frequencies: 6448, 7515, 8587, 8565, 9255, 9655

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6448 ----> Not Hypnotoad
7515 ----> Confirmed Hypnotoad
8587 ----> Hypnotoad may have been here, but at the time of checking it is the Japanese Slot Machine [XSL]
8565 ----> Unconfirmed Hypnotoad
9255 ----> Unconfirmed Hypnotoad
9655 ----> Unconfirmed Hypnotoad
6500 ----> Suspected Hypnotoad [Must be investigated, unsure]
So I conducted yet another scan at 23:00:00 CEST | 21:00:00 UTC. Here is what I got after processing the scan of the HF bands.

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Suspected frequencies as of the 23:00:00 CEST scan:
8587, 8565, 9255, 9655
Cleared frequencies: 6500 ----> Not Hypnotoad
So, a friend of mine brings a video to my attention of a signal that sounds just like the hypnotoad but it buzzes every second instead of being continous, I have heard this signal before but somehow had not connected the dots. This is the video https://youtu.be/uhQftJJ2Dj8, the signal in the video is 3 kHz wide, as your average SSB transmission, same audio frequency of the buzz. While on the other hand, the hypnotoad is about 10 kHz wide and has the buzz as a continous signal.

Just as he did that, I have spotted 2 new frequencies on

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7396 kHz and 8920 kHz.

After watching his video and connecting the dots, a new scan from 02:44 CEST | 00:44 UTC has spotted the hypnotoad but in a similiar way as in the video, it is 3 kHz wide but continous buzzing.

A waterfall screenshot of the 3 kHz hypnotoad.

Once that was done, 3 new frequencies were spotted:

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6620, 6370 and 6380 kHz.

This is a list of the frequencies that the hypnotoad has been heard on so far, and frequencies that have yet to be confirmed.

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Frequencies: 5247, 6620, 6665, 6370, 6380, 6700, 7515, 7353, 7396, 7753.5, 7920, 8110, 8270, 8188.5, 8380, 8800, 8920, 9150, 9413, 9695, 9920
Unconfirmed Frequencies: 8587, 8565, 9255, 9655
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1st September 2025

2 scans were conducted at 17:30:00 CEST | 15:30:00 UTC and at 18:48:44 CEST | 16:48:44 UTC.

I have found nothing regarding the hypnotoad. Not even under 10 MHz. Above 10 MHz was empty in regards to the hypnotoad.

A scan conducted at 19:11:52 CEST | 17:11:52 UTC lead me to new discoveries as listed below:

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Unconfirmed Frequencies: 8587, 8565, 9255, 8670, 9810, 9700, 12280
Suspicious Frequencies: 6245, 6520, 8250, 9010, 10520, 11700
Cleared Frequencies:
9655 ----> Not Hypnotoad

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6th September 2025

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New frequencies: 8998.5 kHz and 7060 kHz
A new scan conducted at 01:40:12 CEST | 23:40:12 UTC intercepted a signal on 7150 kHz, a very wide signal in the middle of the 40m band. Thinking that this is just the 29B6 radar but weaker, I checked out the signal myself and it was the hypnotoad, but this specific signal is 40 kHz wide.


A picture of the 7150 kHz hypnotoad (as seen on the left)

The hypnotoad switching from a narrow 3 kHz bandwidth to the 10 kHz bandwidth
https://www.youtube.com/watch?v=sVpEOknYLcc

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9th September 2025

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New frequencies: 5315 kHz and 6020 kHz
A new rare frequency has been spotted today at 13:28 CEST | 11:28 UTC!

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New frequency: 15945 kHz


The hypnotoad on 15945 kHz

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10th September 2025

A new frequency has been spotted today at 04:53 CEST | 02:53 UTC

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New frequency: 5530 kHz

Today, while I was checking out my old videos on Youtube, I noticed this video called "Jammer on 41m band", I clicked on it wondering what it was just to see it was the hypnotoad. This is the video: https://youtu.be/-Pd_0GQW_7o?feature=shared

A new frequency has been spotted today at 22:16 CEST | 20:16 UTC

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New frequency: 6878 kHz

A new frequency has been spotted today at 23:17 CEST | 21:17 UTC

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New frequency: 5575 kHz

A new frequency has been spotted today at 23:50 CEST | 21:50 UTC

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New frequency: 5251 kHz


If anyone has any information or frequencies that they believe is the hypnotoad, feel free to reply to this thread <3

[BoomboxDX]

What exactly is a 'hypnotoad'? Never heard of this before.

[Antenna101]

Hey, the "hypnotoad" is a signal on HF that sounds like "yayayayaya", this signal has a couple of modes. A mode that was most likely used by the hypnotoad last year was the "buzzer" as seen here https://youtu.be/uhQftJJ2Dj8. Since then, the hypnotoad has switched to a continous transmission all across HF, can be 3 kHz wide or even sometimes wider, mostly up to 10 kHz. This is how the hypnotoad sounds on 6020 kHz: https://voca.ro/1o2Z49Lp0d9l (recorded 5 minutes ago). The origin of the signal is unknown but TDoA results have been leading me to the middle east, a precise location yet to be found.

[BoomboxDX]

The YT clip sounds a bit like the famous Buzzer, as you said.

Interesting. Keep us all posted.