S-Parameter Test Set for the SDR-Kits VNWA, page 4
And here it is … the completed S-Parameter Test Set. Left to right: USB-controlled
switch, Transfer Relay, VNWA. Like the relay, the aluminium box was found languishing
in a cupboard. The bulkhead mounted SMA barrels were salvaged from military kit,
so are good quality. The green LEDs above the front panel SMAs indicate which one
is currently the RF source.
Note the use of two USB ports. There is a USB output connector on the VNWA but I
have never been able to figure out how to use it … or if it can be used. I know that
if I plug my ATTiny45-based USB device into it my PC reports it as an unidentified
device and refuses to acknowledge the driver … hence the two USB ports.