S21SDR — FT8 activity observed at SO8OO

DXCC entity inferred from callsign: Bangladesh Most frequent locator attributed to this token: NL53

Receiver-side FT8 activity involving S21SDR, decoded by SO8OO in southeastern Poland. 4 FT8 messages attributed to this token as transmitter, on 80m, 20m, across 2 UTC dates in the available aggregate history. Observed between 2026-07-09 and 2026-08-25.

These are automated observations at the SO8OO receiver, not an official contact log. Times are UTC. Attribution follows decoded FT8 message structure: CQ uses the first token and directed-looking messages use the second. Free text that resembles a directed message can be attributed imperfectly. Summary S/N reflects propagation plus SO8OO receiver, antenna and local-noise conditions. Counts are not adjusted for monitoring outages; transmissions that were not decoded are absent. Inferred entity and location data may be inaccurate for portable, remote or special-event operation.

SO8OO decoded 4 FT8 messages attributed to S21SDR as the transmitting token by decoded message structure across 2 UTC dates in the available aggregate history. The available sample contains attributed decodes on 80 m (75%) and 20 m (25%). The sample is too small to infer a recurring UTC-hour or received-S/N pattern.

Overview

Messages attributed

UTC dates decoded

Active 15-min windows

S/N pattern not inferred

Bands

80m · 3 20m · 1

First attributed message: 2026-07-09
Last attributed message: 2026-08-25 15:02 UTC

Observed FT8 message patterns

Attributed sample: 4 messages
Active dates: 2 UTC dates
S/N summary: Too few decodes
S/N percentile sample: Too small
Recurring-pattern threshold: Not met

WSJT-X defines S/N reports against a 2,500 Hz reference noise bandwidth. The ranges above are SO8OO receiver-side display categories, not official WSJT-X classes, transmitter-power measurements or estimates of how easy the station is to hear elsewhere. Statistics include only successful decodes on SO8OO's monitored FT8 channels; transmissions that were not decoded are absent. The sample does not meet the threshold for a recurring time or signal-pattern claim (20 attributed messages, three UTC dates and five distinct 15-minute windows).

Frequent counterpart tokens observed at SO8OO

Tokens most often paired with S21SDR in decoded directed-looking exchanges:

RA3QUA · European Russia ×2 S57MPU · Slovenia ×2 DK2LG · Fed. Rep. of Germany UR5ZHJ · Ukraine RY3D · European Russia UA3GDJ · European Russia RW3DW · European Russia UR1CCT · Ukraine E21AZ · Thailand YO4NT · Romania DL70ESSEN · Fed. Rep. of Germany YO8PS · Romania

Most frequent locator attributed to S21SDR

The map compares the centres and boundaries of the locator field attributed to this token by decoded message structure, 2° × 1° as a Maidenhead square, and SO8OO's six-character receiver square. The separation is not an exact antenna-to-antenna distance or a radio-path length.

Attributed locator: NL53 · 4 decoded messages
SO8OO receiver locator: KN09VW
Locator-centre separation: 6,563 km (approx.)
Last such locator decoded: 2026-08-25 15:02 UTC

A decoded locator can describe portable, remote or special-event operation and is not proof of a permanent station address or transmitter identity.

Observed FT8 exchanges

S/N cells show: decoded at SO8OO / report transmitted by the counterpart. An observed exchange is not a QSL or an official logbook confirmation.

Time UTC	Band	S21SDR S/N	Counterpart	Counterpart S/N	Msgs	Capture
09-11 16:42	80m	- / -	OH6FSG	+4 / -	4	Partial capture
09-11 16:41	80m	- / -	UF3T	+11 / -	12	Partial capture
09-11 16:38	80m	- / -	DJ7M	+15 / -	6	Partial capture
09-11 16:38	80m	- / -	OH6FSG	+6 / -	4	Partial capture
09-10 20:44	80m	- / -	LZ2VQ	+1 / -	3	Partial capture
09-07 17:13	80m	- / -	DJ7M	+13 / -	9	Partial capture
09-03 17:36	80m	- / -	DK1AQ	-8 / -	4	Partial capture
09-03 17:34	80m	- / -	LY8O	-4 / -	3	Partial capture
09-03 17:33	80m	- / -	RA3OR	-9 / -	2	Partial capture
09-03 17:31	80m	- / -	SP6DNZ	+13 / -	2	Partial capture
09-03 17:30	80m	- / -25	UA1OIZ	-8 / -	2	Partial capture
09-03 17:30	80m	- / -	YO2MNZ	+10 / -	8	Partial capture
09-03 17:29	80m	- / -	LZ1GC	+11 / -	3	Partial capture
09-03 17:28	80m	- / -15	LY7M	+7 / -	4	Partial capture
09-03 17:24	80m	- / -	SP6DNZ	+18 / -	2	Partial capture
09-03 17:24	80m	- / -22	YO4NT	+7 / -	6	✓ Closing fragment
09-03 17:23	80m	- / -	R2WAF	0 / -	3	Partial capture
09-03 17:23	80m	- / -	RA3OR	+1 / -	4	Partial capture
09-03 17:23	80m	- / -	UR4LBG	+2 / -	6	Partial capture
09-03 17:22	80m	- / -	LY8O	+2 / -	3	Partial capture
09-03 17:21	80m	- / -	UA9LP	-14 / -	8	Partial capture
09-03 17:20	80m	- / -15	JA2KVD	-21 / -	2	✓ Closing fragment
08-31 19:09	80m	- / -15	OH3EX	+1 / -	3	Partial capture
08-31 17:59	80m	- / -	4X1UF	-7 / -	20	Partial capture
08-31 16:02	80m	- / -15	RY3D	-13 / -	9	✓ Closing fragment
08-30 17:05	80m	- / -	IK5CHL	-8 / -	11	Partial capture
08-30 17:01	80m	- / -	UX5UO	+6 / -	2	Partial capture
08-30 16:38	80m	- / -	OG8A	-9 / -	3	Partial capture
08-30 16:34	80m	- / -	RM8W	-16 / -	2	Partial capture
08-30 16:32	80m	- / -	RC2DD	-2 / -	3	Partial capture
08-30 16:32	80m	- / -	UX1AA	+1 / -	5	Partial capture
08-30 16:18	80m	- / -	UA9AJK	-5 / -	3	Partial capture
08-30 16:16	80m	- / -	SQ3M	+5 / -	2	Partial capture
08-30 16:15	80m	- / -	YO9IJP	-1 / -	7	Partial capture
08-30 16:13	80m	- / -	OH3MMF	-6 / -	3	Partial capture
08-30 16:13	80m	- / -	UA1OIZ	-8 / -	5	Partial capture
08-30 16:12	80m	- / -19	RW9WT	-19 / -	6	✓ Closing fragment
08-30 16:11	80m	- / -	RX6CC	+8 / -	10	Partial capture
08-30 16:11	80m	- / -8	RW9AW	-13 / -	6	Partial capture
08-30 16:10	80m	- / -1	OH7LXL	-17 / -	5	Partial capture
08-30 16:10	80m	- / -8	RD9D	-11 / -	7	✓ Closing fragment
08-30 16:04	80m	- / -	UA3ZUX	+1 / -	6	Partial capture
08-30 16:03	80m	- / -	RX6CC	-2 / -	11	Partial capture
08-30 16:03	80m	- / -	UR9QQ	-6 / -	10	Partial capture
08-30 15:59	80m	- / -	UR9QQ	-10 / -	2	Partial capture
08-30 11:07	10m	- / -	F4EZJ	+2 / -	3	Partial capture
08-30 11:01	10m	- / -	EA3AKY	+3 / -	3	Partial capture
08-29 19:20	20m	- / -13	IZ4TOA	-4 / -	3	✓ Closing fragment
08-29 19:17	20m	- / -	F4BYA	-2 / -	4	Partial capture
08-29 18:45	20m	- / -	UA3AGW	-18 / -	2	Partial capture

Recent FT8 messages decoded at SO8OO

Frequency values are decoder audio offsets in hertz, not RF frequencies.

40m

UTC    dB Audio  Message
175915  -3  433  S21SDR RM5F 73
175915  -6 2254  S21SDR SP7IIT R-19
175915 -10  359  S21SDR YO7ARZ KN14
175945  -7 2254  S21SDR SP7IIT 73
175945 -10  360  S21SDR YO7ARZ KN14 (x2)
180045  +8  358  S21SDR DM5KM -15 (x4)
175515 -17 1718  S21SDR UN7FHC MO82
175545 -14  964  S21SDR UA9UFJ R-06
175945 -15 1277  S21SDR RM9WU LO74
163630 -17 1193  S21SDR R6DZO -07
210845  -8 2057  S21SDR R7LV KN97

80m

UTC    dB Audio  Message
164245  +5 2224  S21SDR OH6FSG KP23
164245 +18  555  S21SDR DJ7M JN49
164315 +11 1140  S21SDR UF3T LO16
164315  +3 2224  S21SDR OH6FSG KP23 (x2)
164345 +11 1140  S21SDR UF3T LO16
164415  +6 2224  S21SDR OH6FSG KP23
164415 +11 1140  S21SDR UF3T LO16 (x8)

10m

UTC    dB Audio  Message
073015  +6 1272  S21SDR DL3GA JN47 (x5)
074215 -19 1520  S21SDR IU0VOG JN61 (x2)
110145  +2 2704  S21SDR EA3AKY JN01 (x3)
110715  +0  513  S21SDR F4EZJ JN05 (x3)
095415  -3  780  S21SDR EA3AKY JN01
095715 -12  596  S21SDR IU0VOG JN61

20m

UTC    dB Audio  Message
154100 -18 2119  S21SDR BA5CW R-08
162815 -12  641  S21SDR R2AL KO85
171915  +4 1768  S21SDR IK4RUX JN54
172015 -17 1176  S21SDR RY3F RR73
150200 -24 1771  N1PPP S21SDR NL53
184545 -13 1770  S21SDR UA3AGW KO85 (x2)
191515 -14 3000  S21SDR PY1EME 73
191715  +6 2913  S21SDR F4BYA JN19 (x4)
192045  +0 2513  S21SDR IZ4TOA JN54 (x3)

Decoder S/N history by band

Count-weighted daily averages across messages attributed to this profiled token and successfully decoded at SO8OO, limited to the rolling 90-day UTC chart window.

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