All electronics related. For finer selection go for sub-categories.
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 […]
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 […]
Some time ago, my old Time Capsule died. It simply did not start. I read that this is an issue that plague all older (first and second generation) TCs. The culprits are four electrolytic capacitors inside the switching power supply, two 1,500 µF, one 1,000 µF and one 470 µF. The 1,500 µF were badly swolen. […]
This will be another short post. I also made the GitHub repo public, but please be aware, current design is flawed. If you use it, you acknowledge that you use it on your own risk. Today I managed to build the revision 1.0 of this power sensor, not without some lessons learned. It was my […]
I ordered the boards for this project with JLCPCB in China. This is my first attempt of working with a professional PCB manufacturer and I am extremely pleased by the results.
My first finished KiCad project is a prototype of a RF Power meter with input attenuation built around an Analog Device AD8307. An excellent tutorial about log amps can be read in March 1999 edition of Analog Dialogue. KiCad PCB: And the 3D rendering of the same PCB: The next step will be PCB ordering, […]
One very interesting feature of Altera FPGAs is that almost any system can be created in its next-generation system integration tool Qsys using a standard library of reusable IP blocks. The system interconnect fabric is automatically generated by Qsys and binds the blocks together. The system interconnect manages dynamic bus with matching, interrupt priorities, arbitration […]
I’ve been quite busy lately and neglected the blog. I enrolled on Coursera for a very interesting FPGA course, in what seems to be a FPGA specialization from University of Colorado Boulder. I have always had somewhat a reserved attitude towards FPGAs mainly because I believed that these are hard to understand and need a […]
This is a beacon project started by my friend YO5VAE. He faced some issues while programming of the Si4463-based module and I thought I might give a hand. I resoldered the entire project on an empty Arduino shield to allow expansion of the project with some additional modules. Below are some pics, but probably the […]
I ordered some ferrite beads for a RF circulator project I currently work on but these might also be very handy for the SWR bridge project. These are extremely efficient for RF supression, or at least this is what they say.
For low frequency projects, a fast way to prototype is using a bare PCB and scratch some dividers that allow “manhattan” style prototyping. I am especially very fond of this prototyping technique and I believe that PCB design should be avoided in the early stages of prototyping. Jim Williams was an artist in such designs. […]
A couple of months passed since I purchased two 10 MHz OCXO modules from eBay. And, to my shame, I didn’t even tried these. Yesterday I did a quick test and the devices are spot on. Both measured on my TTi TF930 3GHz frequency counter: The OCXO needs apx 10 minutes for proper warm up […]
Power supply: DC 9v – 12v Antenna: 50 ohms, is not balanced, 7MHZ band, standing wave ratio below 1.8 Receive the static current: 10 mA @ 9 v Transmission power: 0.8W @ 9 v, 1.2W @ 12 v Frequency range: 7.023 MHz launch, receive 7.023-7.026 MHz (7.023 MHz crystals) Stray (harmonic) inhibition: – 20 db […]
I am pretty pleased by the outcome of my commercial endeavours on eBay. Purchasing seems to be a pleasure; until now — with just one exception — I was spared from any nasty experiences. After several small items that I ordered in part for my curiosity to evaluate speed and quality of shipments from chinese suppliers, I […]
I’ve kept drooling for this for several years. Today I finally got it ! Moreover, it seems it is fully-option enabled, which is kinda weird because I haven’t ordered for such. However, here it is: the Rigol DSA 815 TG Spectrum Analyzer with tracking generator. This will enhance my lab’s capabilities in RF electronics and […]
