Market Reef is to the southwest of the Aland Islands in the Bay of Finland. I hope you can read Eric's charming and humorous description of the island and the operation on side 2 of the card.
This operation participated in the CQ Worldwide CW Contest in 1993. I found
OJ0/OH2BBF up in the RTTY segment of 20 meters - in fact, his signal was UNDER a
strong RTTY signal! I don't think he had a very good rate up on that frequency
(at least with the USA) but I managed to work him somehow for an all-time new
country.