Ismo (OH2FTG) recently introduced me to a bunch of Tokmas RF parts. Out of these, the Tokmas CID10N65F GaN FET stood out. It seems to have a lot of potential (for HF + 6m) at a very low price point. This RF MOSFET part can be purchased from LCSC. It seems Tokmas CID10N65F has the potential to completely replace the RD16HHF1 part from Mitsubishi Electric! Datasheet excerpt: The full datasheet is available here. ...
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 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 lying 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 an 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
My homebrewed PA0FRI Active Antenna is working well from a very physically constrained location. 3D render: Schematic: Results: The antenna is connected to a RSP1 Clone SDR which is running custom FT8-band-hopping software. I am using a SOLID 4-Way 5-2400 MHz RF splitter to connect multiple SDRs to the same active antenna. NB: Plug in 75-ohms dummy loads (terminators) on the unused ports of the RF splitter - MX-282 / MX-280 75-ohms dummy loads work fine. ...