Hi Barry,
I don't know that you would need to do the whole copy around thing. I
haven't tried it, but I think it would work fine selecting a calibration
slot, slot 1 for example, and then using NanoVNA-Saver with the device with
that calibration active in the calibrated range.
*However*: My personal preference is to have Cal 0 be full span, and then
making a calibration within NanoVNA-Saver, using the calibration assistant,
with the "Segments" count set to perhaps 10 or even 20 - which gives you
1010 or 2020 data points for the calibration. This calibration can be full
span, or for the range you are interested in. You can then save this, or
any other calibration you make, as files which you can name more
intuitively than "cal 0", "cal 1" etc. ;-)
It's worth noting, that any calibration in NanoVNA-Saver is in reference to
the particular calibration done on the NanoVNA: So if you re-calibrate your
NanoVNA, your NanoVNA-Saver calibration ceases to be valid, and may give
incorrect readings.
--
Rune / 5Q5R
On Tue, 12 Nov 2019 at 01:26, Barry Jackson via Groups.Io <G4MKT=
[email protected]> wrote:
On 08/11/2019 15:18, Nick wrote:
> Thanks Rune. I did not understand the relationship between device
cals and nvna-s cals.
>
> Please allow me to check my understanding.
>
> Let's say I want to measure a ferrite choke from 1 to 50MHz. I set
up the cables and do a device cal over that frequency range using an
appropriate cal kit. I save that cal to say C0.
>
> With C0 selected on the device, I repeat the cal on nvna-s using the
same frequency range, same cables, same cal kit and save it to cal_0.cal.
>
> I can then measure my choke over the same frequency range using
nvna-s with as many data points as I like using multiple segments.
>
Yes
> Let's say I then want to measure a UHF filter over the range 100MHz
to 900MHz. Obviously I cannot use C0 and cal_0.cal. So I set up with
different cables and a different cal kit. I do a device cal over that
frequency range and save it to C1.
>
No. According to my understanding from Rune. On connection nvna-s reads
cal data from Memory 0 only, so unless your calibration originally
covered the whole of the frequency range and was saved to C0 then as far
as I understand that would not work.
> With C1 selected on the device, I repeat the cal on nvna-s using the
same frequency range, same cables, same cal kit and save it to cal_1.cal..
>
> I can then measure my filter over the same frequency range using
nvna-s with as many data points as I like using multiple segments and
save the results to s*p files.
>
> What if I then want to measure the filter over a restricted frequency
range, say 400 to 500MHz?
>
> Or a VHF filter with the same the cables and connectors from 100MHz
to 200MHz?
>
> Do I need a new pair of cals in either of these cases? (I would say
not.)
I would say that unless you make a full span course cal and use that
from C0 then you would need to save manual cals for the other ranges and
store them in C1..C3 and copy them to C0 before disconnecting from the
nvna and reconnecting to pick up each new cal from C0.
Maybe Rune can clarify whether or not I have misunderstood his comments
in
Barry
G4MKT
