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This is the original nanovna I purchased (after which I started [email protected]) in May 2019. The firmware is as was shipped/delivered, never updated (although I started the group and have enjoyed the many discussions since then, I've had little time to use the device.

Question is this - after SOLT calibration at the female device port (no jumper except for the thru test, using the O S L parts that were delivered with this nanovna device in mid 2019), reflection loss S11 with open port does not match expectation.

Frequency limits set to 1 and 100 MHz, followed by OSLT calibration at the device ports. Repeated this to reduce chance of operator error. The standards are those that were shipped with the nanovna in 2019. Device is running with it's internal (original) battery, fully charged.

With port open, S11 shows 7.5 dB (not ~0 dB; starts at 7.50 dB ends at 7.53 dB) across the frequency range (visible both with logmag and smith chart formats.)

With port shorted, S11 is ~0 dB across the frequency range.

With port terminated, S11 is ~-80 dB across the frequency range.

Transmission loss (S21) is < 0.5 dB across the frequency range (0.2 to 0.5 dB).

I do not recall seeing S11 with open port of this nature in the past, although again I've made little use of the unit since new.

Am I doing something wrong? Does this seem like a device issue?

Thanks,

Dave

Hi Dave,

Did you execute the RESET command prior to any cal?

I have the same antique and a one port only device and to date, zero issues.

Alan

Hi Alan,

I'm afraid I've never connected the device to a PC (!), and there is no Reset command in the device's menu tree.

Dave

Hi David,

See message # 896, the pdf and then go to page # 6 in that document. A sample of the document below. Please note the RESET command, item 18. Your RESET command as part of a soft key function should be there. No PC etc... required. Source is original firmware from 2019.


Tap the screen again and continue.
13. STIMULUS
14. START 50 kHz.
15. STOP 900 MHz.
16. BACK
17. CAL
18. RESET
Note 10:
Invoking the RESET command at this point is key to a proper calibration sequence. The RESET
button will highlight and stay highlighted. Invoking the RESET function will destroy all the
previously saved calibration data. It is now imperative that this procedure run to completion to
generate new data. Now continue.
19. CALIBRATE

Alan, thank you - that fixed the issue!

Dave