Circuit6040 - Home Page - N3FJZ


What's new:
2020-06-26 - Several wiring additions have been made to the ZX-Front-Panel schematic to support the inclusion of PTT (Push To Talk) control via the Arduino controller. If you've built the ZX-Front-Panel from an earlier schematic (prior to 6-26-2020), you'll need to make the following wiring additions to be able to use the new PTT control functionality in firmware releases dated 6-26-2020 (20200626) and later:

- Add a connection from an external N.O. (normally open) momentary switch and capacitor to pin 38 of the Arduino to ground. This is the connection from the PTT switch, typically on the microphone, that when grounded (pressed) indicates that the operator wishes to Transmit.

- As shown in the ZX-Front-Panel schematic, add a 2N3904 (or any general purpose NPN switching transistor), two resistors, and a capacitor between the Arduino pin 39 and the rig's /PTT (active low) control circuit. The /PTT (active low) line typically controls the PTT relay or other power control mechanism that, when low, switches the RF circuits from Receive to Transmit.

By passing the PTT request through the Arduino, features such as shutting down the transmitter when the final transistors get too hot or when there's a high VSWR, limiting the time the transmitter is on, preventing transmissions outside the Amateur band, putting the transmitter into 'Tune' mode, and implementing a station I.D. reminder timer, et cetera, will be possible.

2020-06-26 - A new build (#20200626) of the Arduino Sketch (source code) is available. This new build implements the PTT (Push To Talk) control via the Arduino controller as described above.

• 2020-06-23 - A new build (#20200623) of the Arduino Sketch (source code) is available. This new build includes the real-time display of the 10 MHz reference on the crystal trim screen on both the color and monochrome displays. This allows the operator to trim the Si5351 master crystal oscillator while monitoring the 10 MHz reference error.

2020-06-22 - A new video (Part 12) shows how to change the default baudrate in the Ublox NEO-6M GPS module using Ublox's U-Center.

• 2020-06-21 - A new video (Part 11) showing the features of the new sketch build (#20200621).

• 2020-06-21 - A new build (#20200621) of the Arduino Sketch (source code) is available. This new build includes a GPS disciplined RF frequency counter that uses the Ublox NEO-6M GPS module's 1-PPS signal as its gate.

• 2020-06-19 - Made several wiring changes to the ZX-Front-Panel schematic in preparation for the inclusion of the frequency counter, a second rotary encoder, and assignment of pins for future functionality. If you've built the ZX-Front-Panel from the earlier schematic (prior to 6-19-2020), you'll need to make the following wiring changes to be able to run any firmware releases dated 6-19-2020 (20200619) or later:
- Move S-Meter input from A10 to A7 (currently this is the potentiometer used during development)
- Move the LED for General Class TX Privilege from 22 to 45
- Move the LED for Extra Class TX Privilege from 23 to 44
- Add the 74LV8154 chip and associated connections to the Mega 2560
- Add a connection from the GPS module's 1-PPS output to pin 7 of the 74LV8154 and to pin A11 of the Mega 2560
- Add the second rotary encoder and associated connections to the Mega 2560

• 2020-06-14 - A new build (#20200614) of the Arduino Sketch (source code) is available. This new build includes indicators showing the license class that has TX privilege for the dial frequency.

• 2020-06-13 - A new video (Part 10) showing the GPS clock on the monochrome display.

• 2020-06-11 - A new build (#20200611) of the Arduino Sketch (source code) is available. This new build includes the ability to adjust the Si5351's output level real-time from the user interface and other improvements.

• 2020-06-11 - A new video (Part 9) showing the new features.

• 2020-06-05 - New Arduino Sketch (source code) and schematic for the new ZX-Front-Panel with color display and GPS linked clock.

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-Projects-
This section contains links to actual construction projects that contain full documentation and source code from which you can reproduce the project. If the notation "(Still in Development)" appears, the project documentation is not yet complete and subject to revision as I refine each module.

-Reference-
This section contains links to other projects I've built, but are being presented as-is for reference only with no plans to develop the documentation beyond what's currently presented.

-Links-
This section contains links to other websites that I've found to be a valuable resource.