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APT preamps

Posted: Tue Jan 24, 2023 4:37 pm
by srcejon
Here's a comparison of a couple of preamps I have for APT.

Here's the S21 plot for the Uputronics 137.5MHz NOAA/APT Filtered Preamp

Uputronics_NOAA_S21.PNG (49.87 KiB) Viewed 138 times

And for the Nooelec Sawbird+ NOAA

SawbirdPlus_NOAA_S21.PNG (46.07 KiB) Viewed 138 times

I measured a NF of around 1 dB for both.