Ramblings

Several years ago when beginning my adventure into homebrew electronics, I remember having discussions on how a project would drive other projects.  I came up with the question, “What came first? The project or the test equipment to help build the project?”

Projects built over the years are typical of any homebrewer. The likes of transceivers such as mono band cw rigs of various bands, sdr rigs, wspr, keyers, antennas, pic and Arduino based projects etc. The need for test equipment other than the typical multimeter was recognized quite quickly so homebrew projects for test equipment as well as commercial equipment was acquired. 

Building one’s own test equipment was not only a cost effective way to get sophisticated gear, but it also gave more insight into the circuits they were probing. I built the AADE LC meter, field strength meter, multi-functional probe, sna, signal generator, frequency counter, sweep generator, semiconductor tester, and numerous adapters, bridges, etc to go along with them.  With better equipment, I began to want to take on more sophisticated projects.

As my experience grew, in some cases I began to question what I was measuring and the results that my test equipment was telling me. How accurate were they really and were some of the results being affected by the way I was doing the measurements. Were some of the results fine and was it my interpretation of them the issue?  Of all the measurements I can now make, the one that gives the most difficulty, is the oscilloscope.  

Recently, a problem with noise on a transmitted signal, I discovered that the problem increased when the probe from the scope was attached while making measurements. I also was having trouble making low rf measurements in areas where I really wanted to probe and see what effect the circuit was having on the signal.  Sometimes I could see a signal and other times not.

Now I’m wondering about my measuring techniques with my scope. In particular the passive probes in use and should I build an active probe?  Would this be the answer to some of the problems I’m having?  

So here we go again. (Not complaining) The LBS project has generated additional projects. (This is good) The SNA was deemed to be a must have and the SNA drove about 4 more sub projects to enhance its use. Now its beginning to look like an active probe is going on the list of things to do. 

Who knows for sure, but another project for the list and hopefully a better understanding of electronic circuits will be had. After all, that's one of the things that makes this hobby so great.

73, Peter