5.532A in the Radio Frequency Table Allocation of Ireland.

Content Type: ITU FOOTNOTE
Title: 5.532A
Description: The location of earth stations in the space research service shall maintain a separation distance of at least 54 km from the respective border(s) of neighbouring countries to protect the existing and future deployment of fixed and mobile services unless a shorter distance is otherwise agreed between the corresponding administrations. Nos. 9.17 and 9.18 do not apply.
Source: https://search.itu.int/history/HistoryDigitalCollectionDocLibrary/1.43.48.en.101.pdf