2015-08-06

SMD soldering at home: Slides

Here are PDF files with slides from my presentations. These are modified versions of the slides I used during presentations. I added some information which will make them usable without my commentary, and incorporated some modifications based on the feedback I received after the lectures.

SMD soldering at home: SMD rework, and some unrelated topics like how to measure frequency response, and how frequency response analyzer works.

Fourth, and the last part of the series. During this lecture I talk about rework done to the MMIC amplifier board which I built during lecture 3, explain how to measure frequency response of a circuit, talk about inner workings of a frequency response analyzer, and in the end I demonstrate that the board really works and amplifies the input signal.

2015-08-05

SMD soldering at home. I'm building a board. Live. Almost successfully.

Part three of the SMD saga. This time I show how to use some of the techniques mentioned in second lecture to build a small power RF amplifier using MMIC.
I explain how to prepare board for placing the components, how to place them and, finally, how to solder the board using hot air reflow process and how to use board preheater. I also explain why reflowing electrolytic capacitors or other sensitive components can be dangerous for them.

2015-06-07

FDM-SW2 and WinBook TW100 - first impressions

I bought recently FDM-DUO, a QRP transceiver made by a small Italian company, Elad. The radio is really nice. The receiver is a bandpass sampling (no downconversion on RF side, sometimes called direct sampling), full SDR design, with all signal processing and demodulation done in FPGA and software on microcontrollers. The transmitter side uses more traditional approach, where the modulation occurs in digital domain at 0Hz IF, and after conversion to analog domain is upconverted to the band of interest.
It's not my first software radio platform (I've already enjoyed for about couple of years experimenting with bladeRF), but FDM-DUO has the big advantage of integrating the digital and analog circuitry with sleek, minimalistic, knobbed user interface in a small, handy package. The radio can be used as an SDR interface to an application running on a computer, but can also be used as a traditional, standalone HF transceiver.

2015-05-28

Problem with USB connector on bladeRF part 2: The Fix

In the previous post I described the problem with the USB connector on my bladeRF. Now it's time to describe how I attempted to fix it.The first attempt was successful only partially, I had more luck the second time, but I will describe it in another post.

2015-04-16

Working with SMD components at home

Few weeks ago, during one of the meetings of the Vienna Wireless Society ham club, I gave a presentation about working at home with SMD components. The presentation attracted quite a lot of attention, so I thought that it might be worth to share the video recording on the blog. There are two parts of the presentation. During the first part I gave a quick introduction about SMD components for people who have no experience with them. The second part was focused on working with surface mounted devices at home.

2015-01-16

Problem with USB connector on bladeRF part 1: The Failure

A few weeks ago my bladeRF almost died. No, I did not electrocute it, I did not step on it, I did not try to make it work too hard, it did not suffer any kind of physical or intellectual abuse. All I did was to try to gently connect a USB cable. One moment I was pushing the plug into the connector, the next moment the plug was sitting completely loose in the metal frame.