🏷️ Basic Information Identification Make: Champion Model: 781A / 78IB Portable Receiver Year: Unknown Generation: Unknown 📋 Manual Details Documentation Manual Type: Circuit Diagram Language: English Page Count: Likely single sheet or few pages Format: Diagrammatic 📄 Receiver Specs Configuration Valve Count: Seven (including rectifier) Wave Bands: Four Features Bandspreading: Electrical Rf Amplifier: Yes (separate stage) Output Stage: Separate valves for battery and mains operation Power Source Operation Modes: Battery and Mains Audio Output Type: Amplified Tuning Tuning Mechanism: Likely variable capacitor Construction Portability: Portable Components Rectifier Type: Valve (specified as part of the seven valves) Signal Processing Intermediate Frequency Stages: Implied by valve count and typical superheterodyne design Frequency Coverage Am Bands: Likely includes Medium Wave and Short Wave bands Fm Bands: Possible, depending on specific wave band allocation Display Tuning Indicator: Likely a dial or illuminated indicator Antenna Antenna System: Built-in or external connection possible