Hi All,
Yes, it looks like GRAVES was offline on the night of the Geminids maximum – there were a number of tweets about this from myself and Richard Fleet at the time – see here and here. The twitter posts include some speculation as to whether this was coincidental maintenance or was in fact a deliberate decision on the part of the GRAVES operators.
There are a number of antenna suppliers. For the GRAVES system that members of the NEMETODE team installed at Dunsink Observatory earlier in the year we used a 3 Element Yagi from InnovAntennas. Having said that, making one yourself is very straightforward and can be accomplished in an afternoon – see Paul Hyde’s instructions here.
Finally, there is lots of useful information and advice / support on detecting meteors by radio on this forum.
Hope this helps!
Best regards, William