SDR-Widget arrived

The SDR-Widget that I wrote about some months ago arrived today. I just unpacked and here is a few pictures:

I am really looking forward getting into this. The little problem I got is that I do not have any Softrock SDR to use it with right now. So it will be used as a normal sound card for a few days.

But I actually have both the Softrock Lite II and Softrock RXTX 6.3 here to be built. They have been in my drawer now for more than half a year but some days ago I started building again on the lite for 30m and no problems so far. I even managed to solder the SOIC chips ! I have been using the QS1R receiver that is some what more expensive SDR than these for some years now, but I really looking forward to use a radio that I have built myself and using only open source software !

A 20 W Dummy Load

This time I have built a dummy load. I got this design from Elecraft. It is 8 100 ohm resistors rated for 3 W each. 4 in parallel first that gives 25 ohm and then in serial with another batch, so in total 50 ohm. I can also measure the voltage and use a graph to find the corresponding power. Max power should be 20 W.

Here is a few pictures:

And by the way, the box is from IKEA.

Test equipment - LC and multi

The number of test equipment here continues to grow. This time it is a LC meter. The circuit I built  is more or less similar to this one:

http://ironbark.bendigo.latrobe.edu.au/~rice/lc/

A big thanks to Göran SM5AWU that had a kit with components that I bought. He also had done the PCB and drilled the holes for me.

I have also bought me a new multimeter. It´s the Vichy VC99 made in China. I bought it on Ebay for $30 including shipping. It has a few more features compared to the one I had before, like auto ranging, frequency counter, transistor and diode testing etc. It´s a little bit too plastic to feel really good, but at a good price I guess. I have not used it so much so far, but already found some minor issues, like it beeps very loud when it auto shut downs and the continuity tester is slow compared to the old multimeter. Maybe I can change the first behavior if I read the manual. I will continue to use both of them. A good buy overall!

Simple signal generator

With a little bit of inspiration from the blog of M0XPD I have built a simple signal generator. The original design is from NorCal QRP club and can be found here. I´m able to create a S1 or S9 signal (more about the s level here) that I can listen to if I´m going to test a receiver. I can change between 4 different crystals/frequencies. As there is no low pass filtering in the circuit there will also be harmonics. Here is two pictures and you can see that it´s been a while since I built it but haven´t documented it until now.

The box by the way is bought at IKEA. I think it was 7 different boxes in one set and quite cheap. Next test equipment in the blog will use one from that set too.

Linux and LTspice

I finally changed over (or should I say back) my main desktop to Linux. This time it is 64 bit Ubuntu 10.10. I have been running Linux for the last 15 years or so, but changed to Windows some year ago and one of the reasons was that the SDR software I wanted to use was only available for Windows. But now I felt it was time to go back. I have not run Ubuntu earlier, previously it has been Slackware, Debian and OpenSuse (in that order in time), but I can only say that I am impressed with Ubuntu today. Everything worked "out of the box". No fiddling with drivers as it has been in the past.

This Saturday I attended a meeting in the ham club with the topic LTspice. If you have not heard about it earlier, it is a software that can simulate circuits. A very good tool I think. The introduction was held by Volker SM5ZBS. You can check out his homepage. It is in German but I think it is interesting and can be translated if needed. On the screen above you see my new Ubuntu desktop and LTspice which is a Microsoft Windows software is running. You may ask how that works? It is running in Wine, a tool in Linux that makes it possible for some Windows software to run in Linux. Works great!

By the way, the circuit that I have laid out is a audio filter I found in chapter 15 in the book CRYSTAL SETS TO SIDEBAND by Frank W. Harris, KØIYE. It a free download as everything I mentioned in this post!