Is there a replacement for BF862? Or do I just need to pick one that I think is close?
Unfortunately there is no direct replacement for the BF862 FET. However, the BF861C would be a good replacement for this FET: https://www.nxp.com/docs/en/data-sheet/BF861A_BF861B_BF861C.pdf
It is very similar device also designed for preamplifiers for AM tuners in car radios, with very few differences like drain-source voltage and transfer admittance.
Retrieving data ...