Projects, past & present - contd.

Modifying the STORNOPHONE CQM 5000 for 2M amateur use.

After basic RF modifications were completed (1997) thanks to an article by 'David Pye', the rig was tuned for use on 2m. I decided I would write a PIC program to control the on-board synthesizer (80 x 25KHz channels) and to drive an LCD display. It had a standard 1750Hz toneburst and reverse repeater functions.

Over the following few years several modifications were applied, such as channel scanning, hold & store.

In 2009 the microcontroller code was modified to provide 160 channel @12Khz spacing.

In 2010, CTCSS tone generation & storage was added, together, although it does not offer CTCSS decoding, each channel tone can easily be programmed from the front panel (The 1750Hz standard tone burst can also be programmed).

In 2011 a back-lit, dual 16 character LCD replaced the original display - making night operation possible. The LCD displays channel number, frequency, CTCSS code letters, signal strength & power o/p.

The transmitter hasan ERP of 15-20watts and the receiver sensitivity is excellent with 12.5KHz narrow band filtering.

All in all, it has proved to very simple to use, making it ideal for mobile use. A one-of project, strip board was used rather than PCB, on basis that if the modifications are ever completed for good, I may just get round to designing a PCB!

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