On Thu, Oct 10, 2019 at 06:50 PM, <qrp.ddc@...> wrote:
Don't try to press OPEN/SHORT/LOAD/ISOLN/THRU menu for second time, for some
unknown reason it leads to the wrong calibration. So, if you failed at some
step, just return to CAL menu, press RESET and start it again.
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I bought a second NanoVNA which just arrived. It had the 2 trace antenna analyzer firmware loaded. I wanted to upgrade to the recent 4 trace software so I:
1. Uploaded the "CLEAR_MEMORY_DFU" firmware.
2. Uploaded the "edy555 Release -0.2.3-oct-7-19" firmware.
3. Performed a RESET_OPEN/SHORT/LOAD/ISOLN/THRU_SAVE0 calibration.
4. Calibration did not take. OPEN/SHORT/LOAD centered in Smith chart. Thru is 10 dB below reference level.
5. Performed a RESET_OPEN/SHORT/LOAD/ISOLN/THRU_SAVE0 calibration again.
6. Calibration still did not take. OPEN/SHORT/LOAD centered in Smith chart. Thru is 10 dB below reference level.
7. Searched the group for advice, but didn't find anything similar.
8. I had never explored "CORRECTION" under the CAL menu, so decided to see what it did. Clicking on it highlighted the "CORRECTION" label and applied the OSLT correction factors to the data.
9. Performed a CAL_Save0.
10. Everything working.
Maybe when I uploaded the "CLEAR_MEMORY_DFU" firmware, the default state of correction being turned on was wiped and loading the new firmware did not restore it. In any event, hope this saves someone else some head scratching. I initially didn't perform a touchscreen calibration and the touchscreen was fine. After I was sure the unit was working, I went back and did a touchscreen calibration to be on the safe side.
Herb
