NanoVNA V2: Rebuilding a Lodestar Variable Attenuator Switch Box

In this video I repair a lodestar attenuator switchbox and verify its function using the new and improved NanoVNA V2 For S21 and S11 measurements. The attenuator was found without a backing and with charred up 1/4 watt resistors. The values for the pi network attenuators are calculated using a mathematica script and the pi networks were constructed from hand picked combinations of typical value resistors. The backing was replaced with a 3d printed part in PLA; shielding this backing with metal was neglected, but presumably aluminum foil or copper tape could be used as shielding.

Overview: (0:00)
Mechanical Hardware Requirements: (2:03)
Calculating the Pi Network Values: (3:19)
NanoVNA V2 Measurements: (5:15)
End: (9:34)

#NanoVNA #RF #Attenuator

Thumbnail Credit: Francis Fletcher

Видео NanoVNA V2: Rebuilding a Lodestar Variable Attenuator Switch Box канала Robert Research Radios