This brings back memories of the microwave lab in school which held the donated network analyzers ($$$) and was behind a keycard door within another lab that was behind its own keycard door.
Still amazed that someone was able to come up with this tool
How times have changed. You can now get a two port (S11/S21) battery-powered color touchscreen NanoVNA vector network analyzer that can do Smith charts, SWR, and all kinds of other things for under $40. I use one to analyze ham radio antennas and it's not perfect, but works well enough for my needs and is an incredible value. The firmware for it is open source, too.
Its performance is nowhere comparable to a real VNA, those VNAs made by Hewlett-Packard in the late 80s are still the golden standard for many labs.
But NanoVNA is great value for the money for anyone interested in radio electronics! For $50, almost nothing beats a NanoVNA, and it's much more effective than the traditional sweep generator setup. You get complex S11/S21 and 900 MHz bandwidth [0], good for measuring complex impedance, the insertion loss of the coax, the frequency response of filters, SWR of antennas, and even basic Time-Domain Reflectometry. The firmware is available under GPLv3 for hacking as well.
I recently used it to experiment different ferrite RF transformers for my homebrew radio receiver, and to characterize frequency response of inductors.
The only thing to beware - since it's a "almost" free hardware design (i.e. FOSS firmware + a block diagram for hardware, only the PCB layout is not available), there are a number of low-quality clones that use low quality components and don't include proper shielding. I recommend hugen79's version ("NanoVNA-H"), he is not the original designer (it was designed by edy555 [2]), but hugen79's version is currently the most common source with reasonable quality, see the picture for comparison. [1]
[0] > 600 MHz uses higher-order harmonics, and is less reliable, but still better than nothing.
paulirwin|6 years ago
segfaultbuserr|6 years ago
But NanoVNA is great value for the money for anyone interested in radio electronics! For $50, almost nothing beats a NanoVNA, and it's much more effective than the traditional sweep generator setup. You get complex S11/S21 and 900 MHz bandwidth [0], good for measuring complex impedance, the insertion loss of the coax, the frequency response of filters, SWR of antennas, and even basic Time-Domain Reflectometry. The firmware is available under GPLv3 for hacking as well.
I recently used it to experiment different ferrite RF transformers for my homebrew radio receiver, and to characterize frequency response of inductors.
The only thing to beware - since it's a "almost" free hardware design (i.e. FOSS firmware + a block diagram for hardware, only the PCB layout is not available), there are a number of low-quality clones that use low quality components and don't include proper shielding. I recommend hugen79's version ("NanoVNA-H"), he is not the original designer (it was designed by edy555 [2]), but hugen79's version is currently the most common source with reasonable quality, see the picture for comparison. [1]
[0] > 600 MHz uses higher-order harmonics, and is less reliable, but still better than nothing.
[1] https://github.com/hugen79/NanoVNA-H/blob/master/doc/clone.j...
[2] https://github.com/ttrftech/NanoVNA
mNovak|6 years ago