QRP kit building: man, I hope this works!

The modified Forty-9er transceiver kit

I downloaded Arduino Projects for Amateur Radio by Dr. Jack Purdum, W8TEE, and Dennis Kidder, W6DQ a few months ago. It’s a really good book with some actually useful projects in it. If you’re new to Arduino, I might suggest starting with Simon Monk’s Programming Arduino: Getting Started with Sketches, but if you’ve got the basics down, the Purdum and Kidder book is great. One of the projects detailed in the book is a direct digital synthesizer VFO controlled by an Arduino and tuned with a rotary encoder. I thought this was an interesting project, but was unsure how to actually use it.

Imagine my delight when the March issue of QST came out and featured an article on building a complete QRP CW radio by Purdum, Kidder, and Farrukh Zia, K2ZIA. The project uses the DDS VFO circuit from the book, and along with a forty-9er QRP transceiver kit. The article describes modifications to the transceiver kit to replace the fixed frequency crystal oscillator with the VFO. The authors have even created at PCB and basic parts kit for the VFO that you can order from Mr. Zia via PayPal.

I started collecting the various parts necessary: Arduino Nano, Forty-9er kit, AD9850 DDS, rotary encoders, and the VFO PCB/parts kit. I also had to collect a few odds and ends for the Forty-9er modifications: 22μH inductor, 150pf  capacitor, Zener diode, and some header pins. I had everything I needed to put the modified transceiver kit together over the weekend. So far everything has gone to plan. Once the VFO kit arrives, I’ll get to work putting the rest of the rig together. I’m anxious and a little nervous to see if it works.

I set a goal this year to activate at least one National Park for the ARRL National Parks On The Air with QRP CW. I’m hopeful that this project will enable me to meet that goal.

5 thoughts on “QRP kit building: man, I hope this works!

  1. I hope it works as well! I am very interested in building this rig also. I stumbled across a mention of it in some forum and a link to Farrukh page.

    Where did you pick up all the components?

    73 KK6PVK

      1. Thanks for the reply Scott, I ended up purchasing everything I needed off eBay and Farrukh’s site last night. Now the long China post wait begins 🙂

        Have you figured out an enclosure yet?

        Good luck with the build, looking forward to reading your next post on it.

        1. I’m glad you found everything you need. I ended up using a cedar cigar box for the enclosure. I cut a rectangle from the lid for the lcd display. The rotary encoder is on the left side. I also added a power switch on the front.

  2. I ordered the board from Farrukh, and the rest of the stuff from China on EBay. Got it all built and it works, to a point. The 49’er only puts out about 1 watt, not 3. The code for the Arduino does not provide any transmitter frequency offset from receive. The T/R pin is not implemented. I am trying to figure out the changes needed to the sketch to give me a tx offset of 600hz to match the sidetone of the 49’er. It was still a fun project, just not real useful in it’s present form. 73

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