Unknown "Hypnotoad" Signals Spotted on HF

[Antenna101]

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.
https://i.imgur.com/qnmmlkq.png
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

[Antenna101]

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.

[Antenna101]

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


[Antenna101]

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