Thanks Hugen's correction. And special thanks to Oristo8 and Larry for maintaining the wiki pages for us to quickly look for useful information.
Regarding the display size, NanoVNA-F's 4.3" IPS LCD is a nice one. But it comes at the cost of price, large battery, and extra weight. Also, its 800x480 resolution requires parallel interface to reach sub-second refresh rate. That's why NanoVNA-F uses 100-pin STM32F103VET6. Another type of 4.3" LCD has 480x270 resolution with parallel interface only. ILI9488 only supports 24-bit RGB at SPI interface, and ILI9486 is reaching end of production. So it seems that this ST7796S based 4" LCD is the best choice in term of price, weight, performance, and availability. Hugen has installed a FFC connector at the prototype, so it should be easy to replace the LCD if desired.
The LCD back light is driven by a DAC pin and a NPN BJT. So it should easy to add firmware support to control back light later.
For the SMA or N-type socket, it's better to have IPX/IPEX/UFL sockets on PCB, and screw the SMA or N-type sockets at the case. This will help prevent the PCB get damaged from screw/unscrew connectors. Then, the female N-type center pin height issue mentioned by Dr. David Kirkby can be solved too.
The jog switch is a difficult one. Edy555 uses GPIO interrupt and software debounce already. I replaced job switch's pull-up resistor from 10K ohm to 1K ohm. It seems to respond better, although not perfect yet. If the pins are exposed, we could either connect to external buttons or rotary encoder.
Regarding the power supply, I would hope to have a way to bypass the voltage pump circuit and use external 5V power supply when quiet power is needed.
About the BLE support, besides the VCC, GND, RX, and TX, do we also need other pins like SELECT, STATE and EN?
Ken
