RS40-B VHF Radio / with integrated AIS transponder only 1.229,95 € | SVB
071-1043-02 King Radio KFS-570B ATC Transponder Controller (C20) | eBay
Trig Complete VFR Package - Radio & XPDR – AllAvionics.com
Portable radio stationTB2 R | TQ
Ken Shirriff on X: "The S-Band Transponder was the main radio transmitter/receiver on the Apollo missions to the Moon, communicating 239,000 miles back to Earth. We've wired one up and transmitted successfully