In these pages you will find some material related to my amateur radio activity; IN3OTD is the call sign assigned to my amateur station in Italy.
To me, being a ham means mostly experimenting with radio-related electronics circuits and devices and I hope that the material you will find here will be useful also for your projects.
Added several new sections:
- LDMOS modeling: a still under development page on how to extract small-signal models for power LDMOS used for HF/VHF amplifiers, with some examples. Large-signal models will be added in ther near future, hopefully.
- From the bench: notes on bench setup for RF measurements, automation and current projects. Currently hosting a page on automated PA IMD measurements.
- Six-port vector network analyzer: a short description of an old project; how to build a vector network analyzer without explicitly measuring phase, but only voltages
- VNA calibration standards: homemade calibration standards (open, short and load) characterized on a VNA.
- Wideband bias tee: how to design a bias-tee with nice performances, starting from an existing design by WB9JPS
- ...and many other small updates
Amateur radio projects
- added a news section, RF power amplifiers, with detailed measurements on a few HF small/medium power amplifiers
- expanded the dummy loads page, with measured performances of a commercial "non-inductive" resistor
- added new designs for a 6 dB hybrid coupler, with measured data.
- glfer 0.4.2 : This new version of glfer SW spectrum analyzer was updated to use GTK+ 2.0 and has some new additional features added, like a new spectral estimator and several spectrum averaging modes. Moreover the CPU load has been greatly reduced, compared to the previous versions.
Version 0.4.2 allows to select any device in /dev as the control device for the transmitter.
There are several (overlapping) sections, where I add new material every now and then, when I find something I think could be of interest also to other hams:
- For the homebrewers, the schematics area with some of the circuits I have built
- Some programs I have developed trying to solve some common design problems. Amongst them, selecting the best parallel and series combination for a given resistance value, designing coils and variometers and single turn loops, compute the inductance of arbitrary coils systems with fasthenry, design minimum-loss bandpass filters, rotary encoders, and so on...
- Of course, there is also the pictures page, with my antenna and its variometer for the 137 kHz band and many others
Please don't forget to sign my guestbook!
Update: the qsl.net guestbook system seems to broken since some time, so the guestbook is currently not available.