HF Mystery Signals

We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

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Subject / Started by	Replies / Views	Last post
READ THIS BEFORE POSTING, what this board is, and getting the most out of it Started by Token	0 Replies 12864 Views	December 01, 2014, 1623 UTC by Token
All 1 PPS pip / pulse / tick logs here please Started by GC « 1 2 3 4 5 6 7 8 9 10 »	138 Replies 69421 Views	December 10, 2021, 1855 UTC by Josh
Mystery signal question Started by jcwilshire « 1 2 3 4 5 »	67 Replies 87261 Views	November 27, 2018, 1340 UTC by ChrisSmolinski
9024 kHz, DSB, oddity, 03 April, 2020, 0420 UTC Started by Token « 1 2 3 4 »	49 Replies 20368 Views	May 04, 2020, 1326 UTC by Token
2 PPS 0130 UTC 29 Nov 2018 Started by Boriken « 1 2 »	23 Replies 10213 Views	December 08, 2018, 0308 UTC by Exo
Need help on multi-tone signal ID Started by caylorman « 1 2 »	19 Replies 9638 Views	January 24, 2021, 1637 UTC by liduck
White Noise Hump 6890 K 2/5/2022 0017UTC Started by JustGreg « 1 2 »	17 Replies 5401 Views	August 12, 2022, 0302 UTC by ~SIGINT~
UNID 5100-5140, 320z Strange data transmission Started by RadRoadrunner	12 Replies 10142 Views	August 03, 2016, 0342 UTC by MDK2
60 kHz wide signal centered on 6890 kHz 22:45UTC 1/7/2019 Started by CaptnKliegle	11 Replies 7180 Views	January 15, 2019, 1812 UTC by R4002
UNID "Time Signal" at 7475 in AM mode Started by Strange Beacons	11 Replies 4604 Views	January 03, 2020, 1638 UTC by KM0NAS
Data transmission 4.997 to 5.005 MHz Started by Mixer	11 Replies 4689 Views	April 04, 2020, 0102 UTC by Token
UNID HFDL Like Signals 5-9 MHZ - Some with CW Started by ultravista	10 Replies 4347 Views	June 27, 2018, 2109 UTC by Josh
New RADAR appearing all over lower HF bands recently Started by CaptnKliegle	9 Replies 9296 Views	December 11, 2018, 0805 UTC by n3ckf
UNID 13925-13975 UTE? Digital? 2354 UTC 16 July 2021 Started by RobRich	9 Replies 3388 Views	July 18, 2021, 2015 UTC by ~SIGINT~
UNID 6988 USB 2223 UTC 09 DEC 2021 Started by ~SIGINT~	9 Replies 3991 Views	January 11, 2022, 2306 UTC by ~SIGINT~
UNID beeping, 13560 kHz AM, 4/7/16 0224 UTC Started by MDK2	8 Replies 6032 Views	August 31, 2016, 0752 UTC by CrackedLCD
UNID 8000 kHz 1434 UTC 10 Jan 2019 signal Started by IQ_imbalance	8 Replies 4854 Views	January 11, 2019, 1911 UTC by Josh
UNID 7000 UNID Mode 0117 UTC 28 JUL 2022 Started by ~SIGINT~	8 Replies 2957 Views	August 01, 2022, 1701 UTC by Token
UNID Digital mode? Noise? on 7570 kHz (WRMI TX 11) 0527 UTC 18 July 2023 Started by nitroengine	8 Replies 2831 Views	July 19, 2023, 1847 UTC by ~SIGINT~
14354 USB? Started by Marcy1	8 Replies 3229 Views	September 19, 2025, 0528 UTC by BoomboxDX

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