JO4JDU — FT8 activity observed at SO8OO

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

Receiver-side FT8 activity involving JO4JDU, decoded by SO8OO in southeastern Poland. 4 FT8 messages attributed to this token as transmitter, on 20m, across 3 UTC dates in the available aggregate history. Observed between 2026-06-14 and 2026-08-23.

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 JO4JDU as the transmitting token by decoded message structure across 3 UTC dates in the available aggregate history. The available sample contains attributed decodes on 20 m (100%). The sample is too small to infer a recurring UTC-hour or received-S/N pattern.

Overview

4
Messages attributed
3
UTC dates decoded
4
Active 15-min windows
-
S/N pattern not inferred

Bands

First attributed message: 2026-06-14
Last attributed message: 2026-08-23 13:23 UTC

Observed FT8 message patterns

Attributed sample
4 messages
Active dates
3 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 JO4JDU in decoded directed-looking exchanges:

Most frequent locator attributed to JO4JDU

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 · 2 decoded messages
SO8OO receiver locator
KN09VW
Locator-centre separation
8,453 km (approx.)
Last such locator decoded
2026-08-23 13:23 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 UTCBandJO4JDU S/NCounterpartCounterpart S/NMsgsCapture
09-02 07:47 10m - / - LZ2II -23 / - 2 ✓ Closing fragment
08-22 14:55 20m - / -3 IU1TLG -6 / - 3 ✓ Closing fragment
08-22 14:53 20m - / -6 RW4Z -4 / - 4 ✓ Closing fragment
08-22 14:50 20m - / -12 ON4AOI -5 / - 2 ✓ Closing fragment
08-17 15:38 20m - / -15 F4MSA -5 / - 3 Partial capture
07-18 16:12 20m - / -23 2D0OMN -11 / - 5 Partial capture
07-18 15:48 20m - / - R7DX -9 / - 3 Partial capture
07-18 15:44 20m - / -7 DK9BF -10 / - 6 ✓ Closing fragment
07-18 15:41 20m - / -5 SP0VIP +1 / - 3 Partial capture

Recent FT8 messages decoded at SO8OO

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

10m
UTC    dB Audio  Message
070600 -11 2499  JO4JDU RN6MA RR73
074715 -24 1691  JO4JDU LZ2II RR73 (x2)
20m
UTC    dB Audio  Message
144245 -16  738  EX7CQ JO4JDU PM64
144330 -21 1765  JO4JDU RR73; E27EEL <...> -02
144815  -4 1973  JO4JDU EW6DM/P -06
145015  -4 1371  JO4JDU ON4AOI -12 (x2)
145315  +3 1935  JO4JDU RW4Z -06 (x3)
145545  -7  935  JO4JDU IU1TLG JN35
145615 -10 1935  JO4JDU RW4Z 73
145715  -7  935  JO4JDU IU1TLG R-03 (x2)
145815 -18 1746  JO4JDU G7SQC -12
132300 -23 1516  KB5YNF JO4JDU PM64
051530 -10  280  JO4JDU W7MTH -04

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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