Hello everybody.
It was necessary to measure the capacitance of the coaxial wire (about 1m), I plan to make a probe for the oscilloscope, but I noticed something odd.
Compared with the device RM219.
Those. ordinary capacitances measure +/- the same way (taking into account the error), in the photo just for example the capacitance is 1 microfarad (yellow) and 10nF (green) ...
But that's it when measuring a piece of cable - the readings differ twice!??? I measured other pieces 50cm ... and 1.5m ... also a huge discrepancy ...
Moreover, measurements of other components are normal ... if there are discrepancies, then they fit perfectly into the errors (and my needs).
Usually I measure something with either a device or a tester and there have never been any problems ... but here an incomprehensible situation arose with the measurement of the cable .. Maybe someone came across? Is it in different ways or features of measuring instruments?
I want to know what to believe anyway...
Or maybe someone will also conduct a similar test (wire range from 0.75 - 1.2m coaxial), will you have discrepancies?
It’s just that later I’ll calculate the compensation capacity and I don’t know what evidence to build on ...
The cable is marked RG58A / U (but I doubt that this is the original ...)
Tester G328A(BGR), firmware costs 1.13k (from Yuriy_K from page 277)
In principle, I can try to flash 1.44m (Thanks to indman,
for help in compiling in due time ...), only the USBASP-programmer threw it somewhere, but I can search(But I don't think it's a firmware issue...) ...
p.s. According to the videos on the network, who made such probes, the capacitance is within 30-45nF for people ... i.e. the readings of the tester in this case are greatly overestimated (I don’t understand the reason), but the readings of the device 219 are, as it were, normal ...
This is probably some kind of feature of measurements by a tester of coaxial cables?