Here's some features I'd like to see in any new design that shouldn't cost much, but would make life/testing/experimentation easier:
- Sockets for CPU boards on any new Raduino design. (Teensyduino has this already, and I think the JackAl does, too)
- Sockets for relays, as these have been a frequent source of failure
- Move any pull-up resistors required onto the Raduino/Teensyduino/JackAl board and not rely on the user to wire them up. Many users either failed to wire up the 4.7K external resistor correctly or had the connection fail later, causing the rig to immediately go into transmit on power-up. This is easily avoided by having the required pull-ups on the Raduino/Teensyduino/JackAl board itself.
- Add 3-pin 0.1" input and output headers/jumpers to each section (Bi-di Amps, Audio Amp, Mic Amp, BPF, PA, LPF, etc) on a given board so that the given section can be isolated and tested independently. For inputs to a section, 1st pin is output from prior section, 2nd pin is input to current section, 3rd pin is GND. For outputs from a section, 1st pin is output from section, 2nd pin is input to next section, 3rd pin is GND. Normal operation uses shorting jumpers across pins 1 and 2 to allow signals to flow thru, but jumpers can be removed and test inputs/outputs connected via molex/etc connectors to pins 2 and 3 (or to all 3 pins if desired). This also makes it easier to replace a given section with an external circuit for experimentation/modification.
- Room for extra I2C headers on the Raduino (Teensyduino already has this, not sure about the JackAl) that the user can install later if desired
- Would be nice if the modular design had the PA on a separate board so different PAs can be used based on user preference. Having different boards for a IRF510 PA, a RD16HHF1 PA, etc, would be nice as the user can pick and choose what they want, or build their own much easier.
- Support for adding additional BPF/LPF for those that want 160M, 6M, etc
- As for the LPF relays, I'd recommend using a relay scheme like that on the mcHF transceiver. Their approach minimized the number of relays (only 4 DPDT relays needed for 4 filters), but still had filter inputs and filter outputs going to different relays.
- Design board so that the Raduino/Teensyduino/JackAl board has no obstructions from parts and/or connectors along the entire edge of the radio board. The Teensyduino had to design in special cut-outs to use with the current uBitX due to obstructions. It would be nice if cut-outs like this were not needed in the future.
- Si5351 on main board, not on Raduino/Teensyduino/JackAl
That's my 2 cents. Take it for what it's worth. :)