On Sat, Feb 4, 2017 at 12:47 pm, Jerry Gaffke wrote:
How would you solve the issue of some new ham with a voltmeter and a Bitx40 that doesn't quite work?
If I were to advise a new ham with just a voltmeter, I'd tell him he needs to learn to walk before he can run, and that if he wants to get into home brewing he should start with something less challenging--for instance a DC receiver kit with a good track record of successful builds. Then maybe get an Arduino and monkey with that a while. Get it to display his call sign on an LCD, play with one of the ADC channels to read the value of a pot, stuff like that. Then get an Si5351 board from Adafruit or Etherkit or QRP Labs and get it to make some RF. He can verify it's working by using the receiver he built.
By now, he (or she) is getting excited because there's been some accomplishment feedback (always positive, never negative) and some sense of making headway. So now he has a signal source and he knows a little MCU programming. Now maybe he can make a simple diode peak-detector type RF probe, and if he wants he can use the ADC in his Arduino to display the probe's reading (compensated in software for the non-linearity of the diode). I suppose he could even get an AD8307 and read the output of that with his Arduino (once he learns a little about logarithms--a Wikipedia article will do for starters).
In the meantime, he's reading everything he can get his hands on about common-emitter biasing, double-balanced mixers, low pass filters, and the difference between resistance and reactance. Before he's hardly aware of it, he's off and running. He might buy one of those cheap-but-good-enough LC meters from China, and if he was still taking my advice I'd suggest he consider springing for an inexpensive oscilloscope--even an old analog one. This will kick his experimenting, testing, and troubleshooting capabilities into high gear.He'll at least know he'll need an SWR/Wattmeter and he might even put one together. They're nice, simple little projects.
*Now* he can take the BitX40 off the shelf and know enough and be equipped enough to make a go of it, and in place of newcomer frustration and discouragement will come some real satisfaction.?
That's how I would solve the problem of some new ham with a voltmeter and a Bitx40 that doesn't quite work.
73,
Todd K7TFC
Todd K7TFC