[G6Tanuki]

Must admit, I have always had a weak spot for the U309/310 JFETs, they were my go-to devices for grounded-gate HF/VHF amplifiers in the past.

It's not always appreciated that JFETs are kinda symmetrical; the source and drain can be interchanged. Indeed, experimenting with such interchanging while using a pulsed noise-source[1] can sometimes get you a significant improvement in the balance between noise-figure and gain in a particular circuit.

Best gain and best noise-figure rarely, if ever, coincide.


[1] usually a diode valve run with the heater at a low voltage so emission is 'thermally limited'.