Okay, got my samples denied because I’m Brazilian and Mini Circuits hates our post office losing their parcels. Back to a discrete filter.
@DL4PD I’ll for sure keep this as a stretch goal, however I’ll first try to solve my immediate problem. Thanks for your suggestion!
@vk5qi Okay, so the general consensus is that the two LNAs would provide too much gain, so I’m scraping that idea. Anyone who needs more gain could add another LNA externally later anyway.
You’re right about the Mini Circuits modules, I’m just afraid of having to tune a filter without proper equipment, so they seemed attractive.
I’m now searching for low-loss inductors. So far, I have find this series from Abracon to be interesting, as they have relatively high Q (min 50), are reasonably accurate (± 2%), cheap (~$0.22/single) and easy to source (I can in a single order buy PCBs from JLCPCB and components from LCSC). Capacitors and other components could also be bought from them, only the LNA would have to be sourced externally. It would come almost as an “on-demand” kit.
The PGA-103+ looks promising, however I’m thinking of sticking with the SPF5189Z as I can’t order from Mini Circuits anyway and the SPF5189Z only has a slightly lower IP3 (~41dB vs ~38dB). Also, the latter are quite cheaper and easier to source from AliExpress.
I’m now getting the hang of QUCS and trying to minimize losses as well as making the filter tolerant to component variations. My biggest problem now is that I can’t make the insertion loss lower than ~5dB (!) even on the first stage, considering Q=50 for the series inductors (as they’re larger) and Q=30 for the smaller, parallel ones. Any suggestions?