Calling CQ is a bit of a drag during the current propagation conditions if you don’t have a nice new radio with the calling feature.
This project used an Arduino Uno to control an ISD1700 Dragon Voice Chip module to implement an auto CQ caller.
There are several ways this can be done:
- Set the Arduino up to control a repeat play function, with the audio out to the radios microphone input including a PTT (Press to talk) output (reasonably simple).
- Fully integrate the device into the audio in and out of the radio using the feed through function of the chip.
This project runs with option two above, seeking to utilise the full functionality of the ISD chip. Unfortunately after some testing and rereading of the specifications it was found that the feed through functionality of the chip only applied to the audio input and not the microphone input. This made it necessary to fit a microphone pre-amp to get to where we wanted.
I have included some photos of the prototype, a circuit diagram and the Arduino sketch for those of you who wish to construct the device. A dedicated circuit board could be designed for the additional circuitry to reduce the cable maze.
These will help with the project:
Winbond ISD1700 Design Guides – http://www.microtechnica.tv/support/manual/ISD1700_Design_Guide.pdf
Best of luck.