I’ll not reinvent the wheel, I found this resouce that explain how a L network works as impedance matching, very clear explained: https://en.baltic-labs.com/2013/04/l-network-impedance-matching/
Author Archives: Luigi
RF Transformer design
Designing RF Transformer can be scary but I found a simple and fast method to do the job done. At the and of this article you shoud be able to design a real RF transformer for impedance matching application. The know data are: input impedance, output impedance and frequency. First of all we need a …
Engraving: from CAD to CNC using free software
I was looking for a metallic protractor to mount on my DIY antenna rotator and I was sure chinese suppliers was the answer. As I found some interesting objects, thay had some limitations: too big or too expensive. So I decided to design my own protractor and engrave it an aluminum sheet using only free …
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The Making of L-Band HRPT 1700MHz Dish Antenna
The dish frame parts are got from a 2mm thickness aluminum sheet. The octagon has 62mm side, the long arms are 520mm x 14mm, the short arms 212 x 14 mm, M3 screws are used to fix. The feed’s arms are made from 6 mm diameter aluminum tube, 410mm lenght. One side of the tube …
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The making of RF filters: the theory
The simplest way to improve the RF receiving quality is to add a passive filter between the antenna and the receiver. The FM 88 – 108 MHz commercial radios broadcast strong signals and even if we are receiving on others frequency, they contribute to get worse sensitivity to the receiver. A stop band filter can …
ADSB# a modded version
When I designed the downconverter Convertino, I wanted to test it with a concrete application. The ADS-B airplan trasponders send signal at 1090 MHz so this frequency perfectly fit to test this kind of downconverter. After I set the local oscillator of Convertino to 1175 MHz, I could see the ADS-B signal downconverted to 85 …
Last creations summay
Since spring 2019 I began to play with RF. I had a cheap USB rtl-sdr stick and I would do something intersting. So I found out this page https://www.rtl-sdr.com/about-rtl-sdr/ a list of interesting things a rtl-sdr stick can do. Receiving NOAA weather satellite was very impressive to me so I immediatelly made a 137 MHz …
Luigi Findanno Makes 