The callsign K9YO with the locator square JO22SA has been reported on WSPR on 80m to 10m since the 28th of June 2021.
The transmitter doesn't seem to be operational all of the time and the WSPR signal has been reported by 47 stations since the 28th of June. The map above shows those who have heard this signal on 28 MHz (10M) which suggests that the transmitter was only on air for a short period.
Does anyone have any info as to why is there a US callsign in the Netherlands???
Update: The LU7AA.ORG website suggests that it might have been a balloon.
