yes it would be for the Graves transmitter. I came across a US site about 18 months ago, but can’t find it again where they provided similar antenna which the supplier would tune to the exact frequency. Is this necessary?
If you were transmitting you might want to tune it more precisely to provide a better match to the transmitter but a 3 element yagi antenna tuned for 144-148MHz should work ok at 143MHz for receiving. (It would be difficult to retune in any case as you would need to increase the length of the elements slightly). For example there is an article on the BAA radio astronomy website showing a 7 element yagi centred on 143 MHz with a flat response over +-7MHz bandwidth, fig 2.9 on page 8 here
Thanks Robin for the info and advice. Now I know where to get the antenna from and that they are suitable can read a bit more to source the rest of the equipment. I read physics, but hated electronics and avoided it.