My New 30m CW QRP TX is finished

This new TX is re-using PA strip I tried in the QRSS MEPT I've changed the Arduino code and added a rotary encoder and LCD.

I've also built a “QSK” board that handles the antenna changeover relay, TX VFO enable/disable and keying the driver stage of the PA strip.

It's still a work in progress….

The boards on the bench :

RBN Spots of me calling CQ with 1W - using the antenna c/o QSK board etc.

I repurposed an enclosure from a previous project and started cramming everything in.

And here it is, finished and incorporated into the shack

The final feature set:

• Arduino (Seeeduino nano) controlling an SI5351 clock board
• LCD Display
  • Frequency
  • RX / TX status
  • Approximate TX Power setting (calculated from PA supply Voltage measured by the Arduino ADC)
• Semi-QSK
  • Internal Antenna C/O relay
  • RX Mute line (ground to mute)
• Variable TX Output power via voltage regulator on DC supply to final class-C IRF510 MOSFET
  • Output adjustable 0.1W → 5W

I considered making a transceiver by putting the phasing RX 30m Phasing Rx and this TX together in one box, with a single Arduino / SI5351 but I decided to keep them totally separate. This harks back to an earlier time when this was a common way of operating. There is much more versatility from this approach.

Page created : 19/07/26 12:20 BST

Page updated : 25/07/26 15:41 BST