Advantages

• By having a SDR embedded in the radio, there are no modifications on the radio's chassis or external hanging wires, or even having to connect a SDR and fiddle with extensions, induction issues or long lossy transmission lines
• This design isolates the SDR port when the radio is in Transmit mode
• Avoid ground loops
• Avoids radiating RF noise inside the radio via an external cable
• SDRs has no filtering, since it is manufactured to accept the whole spectrum, and suffers chronically with strong signal images. By taking advantage of the transceiver's preselector filters you get a lot cleaner spectrum output.
• You do not need to use external clumsy antenna switches to your radio / SDR - and losses
• You have access to HF, VHF and UHF bands just by selecting the band of interest in the radio
• Takes full advantage of the FT-991/A preselectors and Bandpass Filters
• While the built-in Scope provides a 1 MHz maximum band width, the RTL-SDR panadapter provides you 2.4 MHz band coverage.

SDR Frequency Span - Red box depicts the SCP span

04 - Building the Board