JH4SLF — FT8 activity observed at SO8OO

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

Receiver-side FT8 activity involving JH4SLF, decoded by SO8OO in southeastern Poland. 7 FT8 messages attributed to this token as transmitter, on 20m, across 1 UTC dates in the available aggregate history. Last observed 2026-06-18.

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 7 FT8 messages attributed to JH4SLF as the transmitting token by decoded message structure across 1 UTC dates in the available aggregate history. The largest monitored-band total was 20 m (100%). In this small sample, the estimated median decoder S/N was -11 dB; no usual signal pattern is inferred.

Overview

7
Messages attributed
1
UTC dates decoded
2
Active 15-min windows
-11 dB
Estimated median S/N

Bands

20m · 7
First attributed message: 2026-06-18
Last attributed message: 2026-06-18 20:29 UTC

Observed FT8 message patterns

Attributed sample
7 messages
Active dates
1 UTC dates
Estimated median S/N
-11 dB
S/N percentile sample
Too small
Recurring-pattern threshold
Not met

SO8OO display ranges among successful decodes: weak (≤ -16 dB) 0, moderate (-15 to -9 dB) 5, strong (≥ -8 dB) 2.

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 JH4SLF in decoded directed-looking exchanges:

Most frequent locator attributed to JH4SLF

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 · 4 decoded messages
SO8OO receiver locator
KN09VW
Locator-centre separation
8,453 km (approx.)
Last such locator decoded
2026-06-18 20:14 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 UTCBandJH4SLF S/NCounterpartCounterpart S/NMsgsCapture
09-20 19:05 40m - / - HB9ELE +7 / - 4 Partial capture
09-17 20:45 40m - / -11 F8FKI +19 / - 2 ✓ Closing fragment
09-17 20:23 40m - / -17 M5BFL +20 / - 4 ✓ Closing fragment
08-25 19:55 40m - / - UA4FKT +8 / - 2 Partial capture
08-25 19:54 40m - / -12 OK2ZAW +18 / - 2 ✓ Closing fragment
08-24 19:16 40m - / -21 LB7ZG +9 / - 3 ✓ Closing fragment
08-24 18:59 40m - / -16 PA3EWP +12 / - 2 ✓ Closing fragment
08-20 19:11 20m - / -19 ON4IQ +20 / - 4 ✓ Closing fragment
08-04 22:51 20m - / -12 CU2AP -2 / - 2 ✓ Closing fragment
08-03 19:00 40m - / -20 SV9GPV -10 / - 2 ✓ Closing fragment
07-30 18:16 20m - / - DL3JHK -8 / - 3 Partial capture
07-30 18:14 20m - / -7 RM4N -4 / - 2 ✓ Closing fragment
07-30 18:10 20m - / - DG6ITP -10 / - 2 Partial capture
07-30 18:02 20m - / -17 RC6OU 0 / - 2 Partial capture
07-30 17:50 20m - / -11 ON4ASV -5 / - 2 ✓ Closing fragment
07-26 19:27 40m - / - UA4FKT 0 / - 3 Partial capture
07-22 21:15 60m - / - ER3ZW +4 / - 2 Partial capture
07-22 21:08 20m - / -15 EA5RR +2 / - 5 ✓ Closing fragment
07-15 19:53 40m - / -15 RW3ZC -2 / - 2 Partial capture
07-15 19:07 40m - / -18 EU4U +2 / - 3 ✓ Closing fragment
07-12 19:31 40m - / -14 HB9EFK -7 / - 3 ✓ Closing fragment
07-11 19:39 40m - / -16 OE3PBS +7 / - 2 ✓ Closing fragment
07-10 19:41 20m - / -15 US5HL +6 / - 2 Partial capture
07-10 19:37 20m - / -17 EA8UP +2 / - 2 Partial capture
07-07 20:22 20m - / -12 IK5AUL -12 / - 2 ✓ Closing fragment
06-30 19:57 20m - / -24 RA3RDN +8 / - 3 ✓ Closing fragment
06-30 19:56 20m - / -13 DL1R +4 / - 3 ✓ Closing fragment
06-30 19:45 60m - / - OE6JCG +2 / - 2 Partial capture
06-26 20:09 40m - / -18 SV2HTW -4 / - 2 ✓ Closing fragment
06-24 20:04 20m - / -13 4O4DB -4 / - 3 ✓ Closing fragment
06-24 18:41 20m - / -20 CT3MD -6 / - 2 Partial capture
06-23 19:53 20m - / - RA4AAT -8 / - 2 Partial capture
06-23 19:17 20m - / -13 UA3GU +2 / - 2 ✓ Closing fragment
06-23 19:03 20m - / -12 5Z4VJ -12 / - 3 ✓ Closing fragment

Recent FT8 messages decoded at SO8OO

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

40m 
UTC    dB Audio  Message
195445 +18  515  JH4SLF OK2ZAW -12 (x2)
195545  +7 2675  JH4SLF UA4FKT LO23 (x2)
183145 -12 2672  JH4SLF UB1AKX KO59
202330 +15 2800  JH4SLF M5BFL -17 (x4)
204500 +17  482  JH4SLF F8FKI -11 (x2)
190515 +11  694  JH4SLF HB9ELE JN47 (x4)
20m 
UTC    dB Audio  Message
181115  -9  745  JH4SLF E70SZ JN84
181145 -10 2732  JH4SLF 4L7T LN21
181415  -3 2387  JH4SLF RM4N -07 (x2)
181645 -10  745  JH4SLF DL3JHK JO62 (x3)
182345 -11  791  JH4SLF RW4HB LO53
225100  -4  816  JH4SLF CU2AP -12 (x2)
184700 -16  722  JH4SLF TT1GD -18
191115 +21 2702  JH4SLF ON4IQ JO20 (x4)
60m 
UTC    dB Audio  Message
194530  +1 1733  JH4SLF OE6JCG JN76 (x2)
211530  +4 2043  JH4SLF ER3ZW KN47 (x2)

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