JA4FKX — FT8 activity observed at SO8OO

DXCC entity inferred from callsign: Japan Most frequent locator attributed to this token: PM64

Receiver-side FT8 activity involving JA4FKX, decoded by SO8OO in southeastern Poland. 1,588 FT8 messages attributed to this token as transmitter, on 80m, 40m, 20m, across 63 UTC dates in the available aggregate history. Observed between 2026-06-06 and 2026-09-20.

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 1,588 FT8 messages attributed to JA4FKX as the transmitting token by decoded message structure across 63 UTC dates in the available aggregate history. The largest monitored-band total was 20 m (72%), followed by 40 m (26%) and 80 m (2%). Most decodes (98%) fell within the six-hour window 17:00-23:00 UTC. Most successfully decoded messages attributed to this token fell in SO8OO's strong S/N range (66%); the estimated median was -5.4 dB.

Overview

1,588

Messages attributed

UTC dates decoded

228

Active 15-min windows

-5.4 dB

Estimated median S/N

Bands

80m · 39 40m · 410 20m · 1,139

First attributed message: 2026-06-06
Last attributed message: 2026-09-20 20:56 UTC

Observed FT8 message patterns

Attributed sample: 1,588 messages
Active dates: 63 UTC dates
Estimated median S/N: -5.4 dB
Estimated 10th-90th percentile: -14.9 to +8.9 dB
Recurring-pattern threshold: Met

SO8OO display ranges among successful decodes: weak (≤ -16 dB) 130, moderate (-15 to -9 dB) 415, strong (≥ -8 dB) 1,043.

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.

Frequent counterpart tokens observed at SO8OO

Tokens most often paired with JA4FKX in decoded directed-looking exchanges:

IK4LZH · Italy ×4 9A6NCC · Croatia ×2 D44AG · Cape Verde ×2 DH2RL · Fed. Rep. of Germany ×2 DL4KER · Fed. Rep. of Germany ×2 DL6MRM · Fed. Rep. of Germany ×2 F1SZC · France ×2 HA1TAB · Hungary ×2 IU2OQT · Italy ×2 LX1RFJ · Luxembourg ×2 ON8PB · Belgium ×2 PD3LKN · Netherlands ×2

Attributed messages by UTC hour

Rolling 90-day UTC chart window. Counts follow decoded message structure: the first token for CQ, or the second token in a directed-looking message.

Most frequent locator attributed to JA4FKX

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: PM64 · 627 decoded messages
SO8OO receiver locator: KN09VW
Locator-centre separation: 8,453 km (approx.)
Last such locator decoded: 2026-09-20 20:56 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	JA4FKX S/N	Counterpart	Counterpart S/N	Msgs	Capture
09-20 20:54	40m	-1 / +2	DL1BJL	+6 / -	7	Partial capture
09-20 20:53	40m	- / -	M8KUG	-9 / -	6	Partial capture
09-20 20:52	40m	- / -6	IU8QTW	-2 / -	2	✓ Closing fragment
09-20 20:48	40m	-12 / -14	PD2ET	-9 / -20	4	✓ Full exchange observed
09-20 20:41	80m	- / -	SP5OXJ	-4 / -	2	Partial capture
09-20 20:41	80m	- / -	R4FDD	-4 / -	4	Partial capture
09-20 20:26	80m	- / -	RT6Z	-1 / -	3	Partial capture
09-20 20:26	80m	- / -	IU1QYF	0 / -	2	Partial capture
09-20 20:20	80m	- / -	RR73;	+26 / -	2	Partial capture
09-20 20:14	80m	-21 / -11	DF0PDF	+10 / -	3	Partial capture
09-20 19:56	80m	- / -	IV3DSG	+4 / -	3	Partial capture
09-20 19:54	80m	- / -	OE6TNO	+7 / -	9	Partial capture
09-20 19:51	80m	- / -	R6OQ	-8 / -	2	Partial capture
09-20 19:51	80m	- / -	SV1DKR	-5 / -	2	Partial capture
09-20 19:49	80m	- / -	EA6Y	+11 / -	3	✓ Closing fragment
09-20 19:46	80m	- / -	IZ0SQZ	-3 / -	3	Partial capture
09-20 19:45	80m	- / -	HB9BLQ	+8 / -	2	Partial capture
09-20 19:44	80m	-16 / -13	RV3V	-8 / -13	4	Partial capture
09-20 19:43	80m	- / -16	ON6AA	+2 / -	5	✓ Closing fragment
09-20 19:10	40m	- / +1	OH8GBO	-6 / -	3	✓ Closing fragment
09-20 19:09	40m	- / -	GM5TGA	-9 / -	2	Partial capture
09-20 19:07	40m	- / -	TA3NK	+3 / -	6	Partial capture
09-20 19:06	40m	- / -	PD4JOH	-10 / -	2	Partial capture
09-20 19:05	40m	- / -	UA3PTY	+14 / -	3	Partial capture
09-20 19:05	40m	-8 / -10	SQ3TR	+8 / -15	5	✓ Full exchange observed
09-20 19:01	40m	- / -	UB3ATT	-2 / -	2	Partial capture
09-20 19:01	40m	-2 / -	DL0ABT	- / -	5	Partial capture
09-20 19:01	40m	- / -	G6PWS	-6 / -	5	Partial capture
09-20 19:00	40m	- / -4	DG5YHK	-2 / -	2	Partial capture
09-20 18:59	40m	- / -	UR4CU	+5 / -	3	Partial capture
09-20 18:58	40m	-8 / -4	G6CUT	+8 / -11	5	✓ Full exchange observed
09-20 18:57	40m	0 / -4	DF6SA	+3 / -16	5	✓ Full exchange observed
09-20 18:54	40m	- / -	DL1FDK	-8 / -	2	Partial capture
09-20 18:51	40m	+2 / -12	M9RDX	0 / -14	4	✓ Full exchange observed
09-20 18:48	40m	-4 / +5	EW6MP	+13 / -8	5	✓ Full exchange observed
09-20 18:47	40m	-5 / 0	US5CDH	+5 / -	4	✓ Closing observed
09-20 18:45	40m	- / -	RR73;	0 / -	2	Partial capture
09-19 18:44	40m	-16 / -7	LZ2PC	-7 / -12	6	✓ Full exchange observed
09-19 18:41	40m	-5 / -18	F4LTP	-8 / -	7	Partial capture
09-19 18:35	40m	- / -	DD8HG	-15 / -	4	Partial capture
09-19 18:33	40m	- / -	G6TAI	-3 / -	3	Partial capture
09-19 18:30	40m	-6 / -13	Z34CMF	-6 / -23	5	✓ Full exchange observed
09-19 18:27	40m	-6 / -	EA1ARJ	- / -	4	Partial capture
09-19 18:25	40m	- / -	DD8HG	-8 / -	6	Partial capture
09-19 18:25	40m	- / -	DL1HTB	0 / -	3	Partial capture
09-19 18:24	40m	-6 / -16	DL6ZOG	0 / -15	8	✓ Full exchange observed
09-19 18:23	40m	- / -	DB7QE	+9 / -	3	Partial capture
09-19 18:21	40m	-6 / -	6K2MAS	- / -19	2	✓ Closing fragment
09-19 18:20	40m	- / -	PC1JB	-1 / -	3	Partial capture
09-19 18:20	40m	-1 / 0	SQ9MA	-10 / -	3	✓ Closing observed

Recent FT8 messages decoded at SO8OO

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

40m

UTC    dB Audio  Message
205300 -10 2906  JA4FKX M8KUG IO81
205300  -1 2067  JA4FKX IU8QTW RR73
205330  -7 2906  JA4FKX M8KUG IO81 (x2)
205415  +0 2487  DL1BJL JA4FKX PM64
205430  -9 2906  JA4FKX M8KUG IO81
205445  -2 2488  DL1BJL JA4FKX PM64
205500  -7 2906  JA4FKX M8KUG IO81
205515  +1 2487  DL1BJL JA4FKX PM64
205530  -9 2906  JA4FKX M8KUG IO81
205530 -14  528  JA4FKX DL9AN -07
205530  +6 2487  JA4FKX DL1BJL +02
205545  -3 2487  DL1BJL JA4FKX PM64
205600  +6 2487  JA4FKX DL1BJL +02
205615  -2 2487  DL1BJL JA4FKX PM64

80m

UTC    dB Audio  Message
201930 +26 2752  JA4FKX SO100PKP -10
202000 +27 2752  JA4FKX RR73; SP2IQW <...> +26 (x2)
202515  +5 2414  JA4FKX SP2IQW -16
202615  +3 2657  JA4FKX IU1QYF JN44
202645  -2  998  JA4FKX RT6Z KN98
202645  -4 2658  JA4FKX IU1QYF JN44
202715  -2  997  JA4FKX RT6Z KN98 (x2)
204100  -2  368  JA4FKX R4FDD LO33
204130  -1 1956  JA4FKX SP5OXJ KO02
204130  -5  368  JA4FKX R4FDD LO33
204200  -6 1956  JA4FKX SP5OXJ KO02
204200  -7  368  JA4FKX R4FDD LO33 (x2)

20m

UTC    dB Audio  Message
191115  -7 1372  F4DXP JA4FKX 73
202330  -2 2732  EA7FPF JA4FKX PM64
202730 -19 1984  EA5JLN JA4FKX PM64 (x2)
204145  -3 2937  F5NKX JA4FKX PM64
204200  +9 2933  JA4FKX F5NKX -11
204215  -6 2937  F5NKX JA4FKX R-17
204230  +1 2933  JA4FKX F5NKX RR73
204245  -5 2937  F5NKX JA4FKX 73
154930  -7 2439  DF2AM JA4FKX PM64 (x2)
155300 -10 1379  YO8RCA JA4FKX 73
155315  +5 1061  JA4FKX RU6FK -10 (x3)

10m

UTC    dB Audio  Message
092030  -4  721  JA4FKX F4ETS JN25 (x3)
092330  -4  719  JA4FKX LZ3BS KN22 (x3)
092730 -12  721  JA4FKX F5BZB -01
094300 +12  556  JA4FKX Z34K -10 (x2)
094630 -21 1562  JA4FKX EA8AP -08 (x2)
095000 -23 1638  JA4FKX F4IBJ R-15 (x2)
083730  -9 2677  JA4FKX IK3VZO RR73 (x2)

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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