I have designed, built and tested an all-HF WSPR beacon which produces 1W @ 5V and is rugged and cost-effective. Power consumption: Around 420mA @ 5V. Cost: Around 500 INR. Time to build: Less than 30 minutes. The files for this project are published here for personal (non-commercial) usage. For a 5W (QRO) WSPR beacon, please hold on for our upcoming QEX magazine article ;) Special shoutout goes to Brad (K1TE) for always pushing me to do better - thank you! ...
I found this 60W Electronic Load to be quite useful for testing small power adapters and supplies. While it is possible to homebrew an adjustable electronic load we recommend getting this electronic load module or a better-but-costlier one like the UNI-T UTL8212+ electronic load. You can stress-test power supplies using this electronic load quite easily and conveniently. It turns out that the Orange branded 12V 2A or 3A adapters from Robu are really trash. The output voltage drops to less than 2V when the load current is increased to around 1A. This is NOT the first time that the Orange branded stuff has turned out to be of poor quality. At the end, you get what you pay for. ...
Tangara is a pretty awesome project - no doubts about it. I found this review of Tangara's design pretty interesting and educational. It has inspired us to build a similar FOSS DAP product but at a much lower cost of 40 USD (that being the launch price of Sansa Clip in year 2007). The idea is to deliver '90% of the value' of Tangara in a slightly smaller (but fatter) and more cost-effective package. ...
I have built probably the easiest, reasonably rugged and most cost-effective 100mW WSPR (or FT8) beacon. Here is my quick and dirty build with whatever I had laying around: We have replaced the traditional expensive Mini-Circuits transformer with a cost-effective Bourns coupled inductor. Power consumption: Before RF generation starts -> 20mA @ 5v. After RF generation starts -> 52mA @ 5v. So the power input consumed in the RF generation process is more than 150mW it seems (which is good). ...
The Easy WSPR Encoder can be accessed here. Update: You may find this software more useful.
Bharath and I have written our thoughts on building a RF lab on a budget. It is geared towards homebrewers and new amateur radio operators. We maintain this documentation here. Have fun! :-)
The Easy FT8 Encoder can be accessed here. In the near future, we want to add the K1JT's original FT8 encoder functionality as well. Update: https://pengowray.github.io/ft8play/ is crazy good!
Notes to get RSP1 working on Linux and macOS using FOSS drivers (2025) Please use a mainstream Linux distribution like Ubuntu 24.04 LTS (or later) or the latest Raspberry Pi OS. Using a Raspberry Pi is NOT recommended as it has quite a bit of power supply noise on the USB ports, which reduces the performance of the connected SDR. On Linux, add the following lines to the /etc/modprobe.d/blacklist.conf file ...
Some weeks back, we published our designs for building reproducible TX-BPF filters easily. 10m TX-BPF: Results of the PCB build: While many amateur radio operators focus solely on antenna optimization, the significant benefits of TX-BPF filters are often overlooked or under-discussed in the hobby! Even with HOA antenna restrictions, you can still optimize your station's performance through proper TX-BPF filtering. We have reduced the cost of such filters by using cost-effective 1kV SMD C0G caps instead of hard-to-get and "probably-obsolete" Silver Mica caps. ...
I am building an easy-to-use and cost-effective WSPR pHAT for Raspberry Pi Zero 2 W. 3D render: We have replaced the traditional expensive Mini-Circuits transformer with a cost-effective Bourns coupled inductor. Results: To be built and tested soon! Time to build: Less than 20 minutes