Thank you for posting such a nice video. I wish you had measured the coax attenuation in order to be able to see the effective value of the insertion loss of the programmable attenuator. Because when you tune the attenuator to be 0dB probably you can achieve only -3dB or whatever actual value of the insertion loss. This will lead to a systematic error between the value present in the LCD and the actual attenuation provided by your device.
I've never seen DIP switches that large before. They look almost like displays in the video thumbnail. I did find one which is selling for $60 plus shipping from Israel.
The marking says the switch is CTS-204-124 which looks like it's available on mouser: www.mouser.com/CTS/Electromechanical/Switches/DIP-Switches-SIP-Switches/204-Series/_/N-5g2s?P=1yzu819Z1ynwx3nZ1yvsm2d, didn't see the 4 position ones but the switch style seems to be the same.
I think that switches like that are actually SPDT rather than SPST, hence they require at least three pins. They may be implemented as a pair of independent SPST switches operated by the same 'knob', with one being NO and one being NC. Hence connecting two pins on the same side of the body of the part makes the 'common' and the two pins on the other side are the other two connections to the SPDT switch.
Luv the work u r doing. I want monitor the capacity of my 14.6v valence batteries shud I use amp connector to rs485 to logic level converter to 4 module relay to arduino. And please how to connect?