My New 30m CW QRP TX is finished

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====== My New 30m CW QRP TX is finished ======


This is re-using the same PA strip as the [[qrss_tx|MEPT]]. I've changed the Arduino code and added a rotary encoder and LCD.

==== Basic Architecture ====

{{:public:radio:img_20260722_114412.jpg?direct&400|}}


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. 

{{:public:radio:img_20260722_113815.jpg?direct&400|}}

It's still a work in progress....


The boards on the bench : 

{{:public:radio:topics:arduino:30m_tx_1.jpg?direct&400|}}

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

{{:public:radio:topics:arduino:20260719_122720.png?direct&400|}}


===== Final Build =====

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

{{:public:radio:img_20260724_220944.jpg?direct&400|}}


And here it is, finished and incorporated into the shack

{{:public:radio:topics:arduino:img_20260725_135239.jpg?direct&400|}}

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

===== Separate TX and RX =====

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.


===== Further Information =====


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

Page updated : ~~LASTMOD~~

{{tag>radio cw homebrew}}

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