I am flabbergasted and depressed.
The
new replacement unit has developed intermittent faults after two days of testing (on top of the black screen problem when i first powered it up
.) It was working fine until today that I have encountered repeated occurrence of these weird faults many times (all random):
1. The Smith Chart is very noisy before after and calibration. The traces are jumping around across the screen after calibration when it is open or with a 50 ohm load (see screen shot of the video). The noise is bad sweeping from 10MHz to 1.5G. It looks more horrible at lower frequency. I switched it on and off, sometimes it is very noisy and sometimes it is normal. I checked the connectors and calibration standards with NanoVNAs. The SMA adaptors are all fully tightened.
2. The TG and VNA are intermittently not working, completely unresponsive ,only showing the noise floor (this was the same issue with the first unit)
I made a number of videos that show the faults as evidence, in case Telonic think I make it up.
The attached images show the results when the unit was working:
(a) Wes Hayward's di-directional amplifier from 100k to 30MHz vs NanoVNA V2, it shows correct response down to about 2.5MHz which is OK.
(b) 467Mhz cavity bandpass filter
(c) A chinese 20db low noise amplifier
When it works, it is great. When it plays up, I am pulling my hair out.