Posts

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. Budget RF Lab Documentation. 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: FT8Play is crazy good!

Notes to get RSP1 working on Linux and macOS using FOSS drivers (2025) Prerequisites 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. Linux Setup 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. Designs 10m TX-BPF: Results of the Dhiru's Manhattan build: Results of the PCB build: Why use BPFs? 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. ...

I am building an easy-to-use and cost-effective WSPR pHAT for Raspberry Pi Zero 2 W. Design 3D render: We have replaced the traditional expensive Mini-Circuits transformer with a cost-effective Bourns coupled inductor. Status Results: To be built and tested soon! Time to build: Less than 20 minutes

I am a bit late to realize that Ubuntu is going downhill and has been for a while. Why? Here are a couple of things I have noticed about Canonical/Ubuntu: Forced paid updates even for active life OS versions Series of bad decisions (Mir, Unity, Upstart, Snaps) causing pain all around Inflicting slow and buggy snap applications on their users. Not listening to feedback from users - Firefox Snap is really slow to launch, especially on older computers. ...

My homebrewed PA0FRI Active Antenna is working well from a very physically constrained location. Design 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. ...

Sometimes we all need a bit of QRO - Life's too short for QRP sometimes. So we give you the Baby-QRO switching amplifier! This Baby-QRO switching RF amplifier design is inspired by the wonderful Single NXP MRF-101 Eval Board project by Jim Veatch. Thank you Jim! Instead of using the expensive MRF101 MOSFET, we use fast SiC MOSFET(s) from Wolfspeed / SUPSiC. Design 3D render: Actual picture: ...

Aim Finding 'Heartbleed' class of bugs with taint analysis. Background reading: https://heartbleed.com/ Motivation While Coverity is now able to detect this bug, we wanted to evaluate the state of open-source security tooling in 2024. Have we been able to reduce the cost of finding such bugs after all these years? The Idea Can we find an execution path from the tainted data in the n2s function to sensitive functions? Since n2s typically operates on network received bytes, it can serve as a taint source. ...

This notebook (aka 'blog') is powered by free solar energy! I was (and am) inspired to start writing again by reading this excellent article by 'LOW←TECH MAGAZINE'. Imitation is the sincerest form of flattery… Tech Stack Tech stack: Navitas 100W Solar Panel, Exide solar charge controller (10A), Exide Solar Blitz 40AH battery, 200W 20A DC-DC CC CV Buck module (Robu), Cuzor Mini Pro RouterUPS (12V), LM2596S DC-DC 24V/12V to 5V 5A Step Down USB module, Raspberry Pi Zero 2W ...