All electronics related. Some overlapping with various ham radio projects but for finer selection go for sub-categories.
I want to get back to FPGA design because I have some projects in mind and I did some in the past that were quite fun and very interesting. I am a bit rusty, though, and I am afraid I have to review all my past, and very diluted, experience with FPGAs. This has a […]
CM108 has a set of four GPIOs that can be used via hidraw. These can be read from or write to.
Today I did some thermal measurements with my Flir C2.
My new radio node that I designed last month is back from production at jlcpcb. Designed in Romania and built in China 😁. This is my first attempt using jlcpcb for the entire manufacturing chain, from PCB creation to part selection and assembly.
There is a problem (or I am doing something terribly wrong !) with the coordinate system in KiCad.
I am already one week into the design of the PCB for my new radio node and today I discovered some schematic errors that I had to fix. Running the DRC (Design Rule Check[er]) KiCad threw some schematic parity errors which “occurs when there’s a mismatch between the schematic diagram and the physical PCB (printed […]
Today I finalzied the designed for my new Raspberry Pi Zero-based radio node. Designed around SA818 and CM108B sound codec, will replace my old dead-bug style radio node that I used for so many years.
More work today. Some wires got loose and I did some experiments with .asoundrc and ALSA settings. I added a 39 Ω ballast resistor on SDIN and SDOUT lines and put a ferrite core on both wires. The radio node works as expected, absolutely no issues with one exception, a periodic pop that is audible […]
Update July 11, 2025 Some thoughts and tasks today. The project is the same I2S interface.
I have some Si5351 chips that I never used for any projects. I purchased them from Mouser, I believe for an APRS project, long-standing and overdue. That APRS project I started some time ago but I never completed and maybe I should strongly consider to complete. But this is another topic.
RDA1846, the transceiver inside Baofeng UV-5R, Yaesu FT-4XR, SA818 and other radios is no longer manufactured. There are equivalent chips that can be used.
Update September, 2024. Activities and notes while developing the I2S interface for my radio node.
Today I managed to connect the Digilent Pmod I2S2 to a Raspberry Pi 4 and have all frequencies generated. This is part of an older project that I left abandoned for a while: a radio node built on Raspberry Pi and using Svxlink. As known, Raspberry boards do not have a proper audio interface and […]
I made this for a friend. Is a remote controller for Yaesu DR-1X repetear that is installed on Summit Heniu (145.725 Tx -6khz Rx). This is a mixed digital (C4FM) and analogue repeater that is covering almost all northern half of Transyvania and can also be accessed via Echolink YO5D-R, node 54452. This version is […]
A couple of days ago I received from a friend of mine a Harris RF power pallet salvaged from a scrapped equipment. This pallet would be able to dissipate apx 300W PEP (black) on a 50 ohm load on ∼800 Mhz. Unfortunately I have no documentation for this. I do have the schematic but is […]
Recently I installed a trial version of the new PCB toolbox from Matlab. From Mathworks website: RF PCB Toolbox provides functions and apps for designing, analyzing, and visualizing high-speed and RF multi-layer printed circuit boards (PCBs). You can design components with parameterized or arbitrary geometry, including distributed passive structures such as traces, bends, and vias. […]
RF prototype boards arrived today from JLCPCB. The service was, as always, very fast and flawless. Seems they have a direct arrangements with Customs because I was not required to pay anything. I ordered 100 pcs for a total amount of 157 euros, apx 1.57 euro per piece. This includes manufacturing and shipment via DHL. […]
This is a general purpose PCB that I designed in KiCad as a helper board for my Manhattan-style mounted RF projects. It allows connection via SMA connector (vertical or edge mount) and BNC. The two completely separated prototyping sections can be interconnected by using the SMAs in the middle or, if you want to save […]
A timelapse of Fusion360 design of the case of the 101dB attenuator project.
I made some progress on my antenna rotator project and installed the stepper drivers and the Raspberry Pi computer. I bought two drivers from ardushop.ro and these should work just fine. They are based on Toshiba TB6560AHQ, PWM Chopper-Type Bipolar Driver IC for Stepping Motor Control. The datasheet can be downloaded from here. My projects […]
I needed this 3D design for a mini N connector that I have in my shack but I was unable to find any 3d file (.STEP etc) online. The connectors are used for my 101dB attenuator project. Enjoy ! Greetings.
My 3D printed antenna rotator project for ham radio satellites. Status 09/16/2021
This is a short video about the progress of my 3D printed antenna rotator. Unfortunately only in romanian for now, but captions will be created soon.
I published on YouTube a video about how to export ecad files in KiCad and import them in Autodesk Fusion 360 to create nice electromechanical assemblies. Captions in english.
A very short clip with assembly test in Autodesk Fusion360: Raspberry Pi and a hat I designed for mobile radio. This type of simulation is extremely useful to pin point issues in mechanical design and assemblies (see at 0:35), that can be avoided early in the manufacturing process. I will create a more detailed tutorial […]
This is mostly a memory helper, to remind me some steps in the setup of Svxlink on Orange Pi Load packages sudo apt update sudo apt install g++ cmake make libsigc++-2.0-dev libgsm1-dev libpopt-dev tcl8.5-dev libgcrypt20-dev libspeex-dev libasound2-dev libopus-dev librtlsdr-dev doxygen groff alsa-utils vorbis-tools curl libcurl4-openssl-dev git rtl-sdr libcurl4-openssl-dev Create svxlink user and add to groups […]
This is not really a post, but mostly a reminder with some information to help me remember the steps. Meanwhile I wrote a much more extensive documentation here, on my wiki (in romanian). And I think I also made a video tutorial but I have to upload it to YouTube. Load packages sudo apt update […]
This is rather a reminder, not a real post. This is a collection of links to help me in my quest to control this device.
I was quite busy the other day trying to understand how Baofeng is using RDA1846 transceiver in their products. While analyzing the schematic it struck me the overcomplicated way they do the switch between UHF and VHF. This is an excerpt of the schematic: The entire selector block is made up with discrete components ! […]
The title of this post might seem a bit too pretentious because it might imply that I am in the position to provide the ultimate recipe on how to train yourself into FPGA. However, it is more like a review on how I did it and some advices based on my limited experience. But this […]
