Stethotracer, a modern copy?
 

I remember there was a kit for something like the Don Bosco Stethotracer. there was also a cheaper version called the "Mosquito" these, as you know, where a signal tracers that where built into what looked like a fountain pen with a ear piece to listen with. The device I remember was built in a narrow circuit board that could be used as it or placed in some sort of home brew case. I cannot think of a search term that will get to it. Does anyone remember it? Hopefully it is still available. As a teenager in the late 1960's I remember Hamradio Gods of radio repair with these "pen things" in their shirt pockets. I would love to get something with the functionality of the Stethotracer, or the Mosquito originals are available but they have become collector's items and are worth more then I am willing to pay for one.

http://www.stevenjohnson.com/donbosc...tracer-kit.jpg

Found it: http://www.qrpkits.com/tracerinjector.html

http://www.qrpkits.com/images/injector1.jpg

IIRC, the "Mosquito" was not a signal tracer, it was a *signal injector* that could be used along with the "Stethotracer". It produced a rather "buzzy" (Mosquito sounding) raspy tone, rich in harmonics that could be injected into the circuit under test, while listening for output with the "Stethotracer".

jr

I saw one of those Mosquito injectors over 50 years ago. I thought it was strange that the firm used the name of a Catholic boy's high school. It was on the south side of Milwaukee and most of the students were from Polish families. You were high-class, in those days, if you went there.
Of course, that wouldn't fly today. Even the trade schools have to be co-ed.

Thanks for the clarification I only remember seeing them in the late 1960's being used by hamradio operators. I have no idea how they worked.