JUMA Amateur Radio Forum

This firmware does not add any new features but significantly simplifies and enhances the out-of-band transmit inhibit logic for SSB. The TX/RX switching logic is entirely performed in the hardware, the microprocessor only senses the status. Consequently, there was no real way of intercepting the PTT transmit request and thus in order to prevent an out-of-band signal being transmitted the mode was changed to LINE I/P which greatly attenuated the microphone signal. With the popularity of modes such as FT8 this was no longer an acceptable solution. Since I couldn't prevent the TX/RX logic from operating, a bit of "lateral thinking" was required. The solution is not to allow a RF signal to be generated, which is achieved by setting the DDS to 0Hz whilst the PTT switch is pressed when out-of-band. As soon as the PTT switch is released the DDS is once again reset to the desired frequency in the RX mode. In the CW modes, there is another way of achieving this, which has always been satisfactory. As there are no EEPROM changes, this should not cause a checksum error and can be safely loaded over a previous version 6. If you are updating from an earlier version, then there will be a checksum error on initial start-up. Make a note of your calibration and configuration settings prior to loading so that you can restore them afterwards. This change does not require a User Manual update. As with all firmware updates, you do so at your own risk.
73, Adrian, 5B4AIY