BitX-20A

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William Waters III - N7IPY

BitX-20A

The basic radio kit is fully contained with there are things that can be added to it or modified to improve it's operation or function. This includes a mod to the tuning to give better range. I thought this would be a fun project to add a home designed and built 'Digital Dial' using one of the Zilog Z8 controllers I have used in the past.

With a design project in mind, below is what I set out to develope:

Frequency Display
Battery Voltage Display
SWR and Power Out Display
Control of the Xmit power if SWR is too high
Control the Keying circuit when in Digital Mode
Fan On/Off Control

Then I thought it would be a fun experiment to try and add digital to the design so I can do PSK31 with the radio. This is still in development and testing.

BitX-20a tune up. The scope shows 80Volts P-to-P at the antenna connector with a 50 Ohm load. This is prior to mounting in the custome case.

Close up of my digital dial electronics. It is split into 2 main PCBAs, one is the CPU logic and the other the SWR bridge.

Testing the SWR Bridge electronics and tuning the data collected in the Firmware to display the SWR and Power graphically.

BitX-20A tranceiver along with Digital Dial Electronics mounted in the Custom made enclosure.

In this view you can see the Audio Interface for PSK31/RTTY. When set for data mode the Digita Dial controls the Keying of the radio based on the presence of data.

In this view you can see that I used Power Pole connectors for power in, and the total electronics package. The toggle switch on the front panel sets the radio in Voice / Data / Stand-By mode.

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