Abstract Superconducting samples of (Y 1−yCa y)Ba 2(Cu 1−xFe x) 4O 8 with y = 0, x = 0.25%, 1.25%, 3% and y = 0.05, x = 0.5%, 1.5%, 3% have been prepared under L.P.O 2 and H.P.O 2. A.C. susceptibility data indicate the presence of weak links. Mössbauer spectra show a large occupancy of Cu(2) sites by iron. At low T, iron orders magnetically with a concentration dependent T N, and even for x = 0.25%, suggesting long range indirect FeFe interactions. This is discussed in connection with present models.