[hpsdr] Switching Devices for HF Preselectors

[Chris Bartram]

Without giving too much away, one current 'Gold Standard' device for switching 
HF signal paths is the (discrete) microwave power pHEMT. Used properly, they 
can have better intermodulation performance than all but the very best 
relays, they also have a longer lifetime, and the costs are broadly similar. 

Bus switches like the '3125 tend to be 15 - 20dB worse.

For a number of reasons integrated microwave pHEMT switches have rather poorer 
performance than the discrete component alternatives.

Microwave power pHEMTs also make very good switching elements for mixers in 
the HF/ VHF region...

Vy 73

Chris
GW4DGU