Cleanly Embedding an RTL-SDR in an FT-991A With No Extra Cables
Thank you to Rodrigo Freire (PY2RAF) for submitting his project that has cleanly turned a standard Yaesu FT-991A ham radio into an RTL-SDR based software defined radio panadapter with no external wires, hubs or dongles.
Rodrigo's system consists of an IF tap amplifier+filter board that is connected to an internally mounted RTL-SDR. The RTL-SDR is internally connected to the FT-991A's USB hub which had to be upgraded from a 2-port hub to a 4-port hub as the 2-ports were already in use by the CAT and Audio features. This required the stock USB hub IC to be replaced with a hot air rework station.
Everything is mounted inside the radio chassis itself, and the end result is a neat solution with no external wires, hubs or dongles that has essentially turned the FT-991A into an SDR. Plugging in the single stock USB cable from the FT-991A results in the standard CAT and Audio interfaces showing up, as well as the RTL-SDR.
What's also interesting is that Rodrigo makes use of the GPIO pins on our RTL-SDR Blog V3 to enable the RX_EN, BPF and BYPASS switches on the IF tap board. This allows for a cleaner solution as no external switches need to be installed.
The entire project is open source with schematics and the BOM provided over on the GitHub, and excellent documentation is available on the project's Wiki.
Nice homebrew kit Rodrigo….and like the regent RS-918 and other small transceiver variants,one would think these manufactures would have a socket for a external display output.
Icom IC-7000/7700/7850/7800 have provisions for an external TV monitor.