Winner winner chicken dinner! Maybe... likely accidentaly... need to have that bastard characterized using better equipment. (I.e. proper two port VNA, which I do not have access to, yet.)
I was able to get ~9dB of gain from it!
The suicide bias wasn that bad at all. I made an guesstimate about hFE - but close. So from the real circuit measurement, I calculated back the real hFE (was exactly the typical value from the datasheet, go figure!), then calculated the correct base resistor. Almost bang on, running it at 19mA. (didn't have 21k, used 22k instead).
I should have made a bigger island with more vias on the upper emitter leg. (I hate hate hate the manual wire-through via soldering!) In a proper PCB manufacture, I wouldn't probably hesitate much to via the shit out of the board. But still, it seems to be (likely accidental) success. Even the simulation predicted 9dB of gain.
What I do not know, is the OP1dB of the amplifier. I do generate the 1627.5MHz carrier from some very old radio-amateur build. It is very unstable, drifting (amplitude wise, frequency is held precisely by an OCXO
) and I cannot vary the output amplitude finely. I can only stack 4dB pads which I salvaged a handful from old equipment.
What I did found, is the output of the 1627MHz LO is not even close to 50ohms. (which one could guess, based on how the LO output is done). By connecting the amplifier directly to the LO output, I cannot get the 9dB gain. If I insert at least one of the 4dB pads before the amplifier, the LO match to 50ohm gets probably better, and then I am able to get 9dB of gain.
Heck.. how a proper RF generator would be handy! Unfortunately, this is very out of my skill to build and very well out of what I could afford to buy, for this kind of frequencies.
Photo, schematic below.
//EDIT: I have added a bunch of BAP64Q PIN diode quads to shopping cart at Mouser, so probably I could use that to vary (and maybe even stabilize the amplitute of the LO source?) By making another piece of this amplifier, I could probably get enough power to probably overdrive the amp and make Pin/Pout measurement by fine adjusting the PIN attenuator. ??