|
Bob Albert
Gary, you hit the nail on the head!? This cute little inexpensive gem is anything but a toy.? I have learned, and continue to learn, a great deal just from playing with it.? Its accuracy is only as good as its calibration, and I have measured a wide range of components over wide frequency ranges to excellent accuracy.
toggle quoted message
Show quoted text
I would put it up against nearly any of the expensive boat anchors out there, at least for ordinary measurements. I always wanted to characterize resistors over the frequency range and this baby does it instantly and correctly.? It shows the effects of lead length, construction type, and so on.? I made up a few test fixtures to make it easy to connect to unknown impedances.? It shows how awful an electrolytic capacitor can be for high frequency.? It will measure characteristic impedance, line length, propagation constant and losses of transmission lines of any length.? Q of inductors, self resonance, the list goes on. I can't say enough in praise of its value.? The only instrument of its versatility and yet I worry about losing it out of my pants pocket. Bob K6DDX On Saturday, August 22, 2020, 03:02:06 PM PDT, Gary O'Neil <n3go@...> wrote:
Hi Roger; I¡¯ve been test driving the firmware for the NanoVNA-H, and it¡¯s -AA sibling on a very early original v3.1 board. Neither offer a Power level control option. I wasn¡¯t aware until your post here that there was a Console command that does this in the H models. I need to look into that. Have you been able to determine if the Console changes are written to eeprom where they would remain until again revised through that interface? Paul (N2PK) and I discovered the issue you describe a couple years back while playing with VIAs that used a strikingly similar archetecture. It was intended as a one port device however that was crudely modified to provide limited two port utility. We observed the high end range compression of the 612¡¯s at that time, in addition to observing source impedance changes of the Si5351 with power level. Paul bypassed the RF front end with one he fashioned with MC1496¡¯s to improve linearity, and he also padded the Si5351 a bit to improve its source match. The overall performance improvement was dramatic. The reductions in size, digital complexity, and price, along with the quality and features made accessible through the open souce firmware offerings, make the current generation of NanoVNA¡¯s quite a remarkable leap forward. It¡¯s shortcomings aside; any of the current NanoVNA derivatives are far beyond ¡°adequate¡± for all but the professionals among us. Only the most demanding of that community would rebuke them. Whats more, the developers continue to appear passionately driven to eek out performance that is indistinguishable from the high end commercial test equipment leaders. It is fast becoming a rather breathtaking evolution IMHO. :-) In the interim, the current offerings are excellent quality learning platforms for the neophytes and budding next generation of RF engineers. Even some of us old dogs might learn a new trick or two along the way.? :-) -- 73 Gary, N3GO |
