Some home brew last night I have this type U310 J-FET also for 50MHz a very stable and low noise design (N6CA) I could not tune the input circuit tried all kind of L/C combinations The amp seems to work okay But saw no S/N improvement on the IC706 144MHz receiving. Already there is an "antenna" noise increment upon connecting the antenna. So improving S/N is not possible anyway this way. Also found that my LED reading lamp IKEA has a nasty electro smog while having the preamp close to it on the desk. No HF smog observed until now. Also 144 had a very bad drifting rattling noise moving over the whole 144-146 MHz from the south. DeJa vue from my 2m magic days long time ago when I was an active 2M DX'r we alway had to fight noise sources even here in the country.