11 Aug
2020
11 Aug
'20
9:47 p.m.
On August 9, 2020 4:57:21 PM CDT, Zach Metzinger via AMSAT-BB amsat-bb@amsat.org wrote:
I've ordered some 433MHz SAW filter (RFMi) from Mouser to install at the output of my homebrew LNA. Hopefully this will reduce overload of the FT-847. A FCDP+, with it's internal SAW, works very well with that antenna and LNA, so I think I'm on the right track.
Success! The SAW filter eliminated the offending cell-tower sources. The noise floor barely moves when the preamp is switched in, while the desired beacon signal increases significantly.
I will be attempting to measure the NF with the Y-factor method.
The exact filter used was SF2446E (Digikey 2410-SF2446E-ND).
--- Zach N0ZGO