[hpsdr] Pennywhistle RF Transistors

[Lyle Johnson]

I note that Pennywhistle is using RD16HFF1 transistors.  While many, if 
not most, instances of these parts work OK at 6 meters, some do not. 
Don't ask how I know!

I suggest considering RD15VHF1 transistors instead.  These will 
definitely have consistent gain at 6 meters.

73,

Lyle KK7P