APT preamps

[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 119 times

And for the Nooelec Sawbird+ NOAA

SawbirdPlus_NOAA_S21.PNG (46.07 KiB) Viewed 119 times

I measured a NF of around 1 dB for both.