开云体育

On Aug 27, 2019, at 4:11 PM, Roger Henderson <hendorog@...> wrote:

Great tip Vince, thanks!

I probably need to do one of those courses, as I don't know python either,
I just figure it out as I go.
The libraries are so comprehensive now that it is very easy to get a result
with a couple of lines of code.

Here is an example of a gated time domain transform on a measurement, I
copied it from an scikit-rf example and just substituted one of my data
files to see if it would work:


So the point is, its not hard to dive in and get something working quickly
- and then tinker with it to understand it properly.

Also Jeff uses Matlab, but some might not be aware of GNU Octave. That is a
free, compatible Matlab alternative - as Matlab is very expensive unless
you are in an education environment.

Roger

On Wed, 28 Aug 2019 at 03:36, Vince Rooney <vince@...> wrote:

For anyone interested in brushing up on their Python skills, there are
many "free" courses available on Udemy if you know where to look. When
new courses are offered to the service, a percentage of them are offered
for free as "marketing". Normally this information was only available to
students of those instructors or services. There is a website called
"discudemy.com" that curates these courses by language. You will need to
first create an Udemy account if you don't already have one so they can
be saved to your account. Note the courses are available for a limited
time or until they run out. You want to locate the courses that have a
price associated to them and are they marked down to $0. These are
usually the full course. Courses without a price are usually "intros"
with little content but worth a look as it may be a new instructor. Also
look at the reviews.

Steps:

Create an Udemy account

Goto discudemy.com and choose your language then search for a topic

There are normally several pages. The front page is current, back pages
may be "expired" offerings.

Happy Hunting!

73, Vince

On 8/27/19 10:18 AM, Jeff Anderson wrote:
Jerry, thank you very much for the link to the paper by Thomas Baier.

I'm glad to see that Dick's and Thomas Baier's results are the same.
Always a good test!

Some years ago I took a short MOOC (massive open on-line course) on

Python, but I haven't used it since, and thus much of what I picked up as
leaked out since then.

I use Matlab a bit more often, so I've retained more of its

idiosyncrasies -- it can be very useful for these sorts of calculations,
and handles complex numbers easily.

Best,

Jeff, k6jca

Hi all,

I've been lurking for a long time, but have now received *my* NanoVNA and
it looks a little different to most I have seen, so I thought I would show
it here. It's black and has the more traditional formed tinplate shielding
rather than no shielding or brass sheet shielding that I've seen.
Purchased from Guangyi0016 on Aliexpress.com on 5 August. I put the
little "feet" on the back to protect the surface. Now I just have to learn
how to use it!

Ross AC3DN

It appears that edy555 has added a TDR function to a Python script in the
ttrftech/NanoVNA repository about 11 hour ago.
Thanks!

Roger, excellent detective work!

I just verified your results -- my NanoVNA results match my 8753C results
if, when calibrating via NanoVNASharp, I do the SHORT calibration first,
rather than the OPEN calibration first.

Regarding the proposed fix of adding a button to reset calibration (a
solution I like the best), another possibility would be to send the Cal
Reset command when the Calibrate button is clicked.

NOTE TOO: I sometimes got weird results after performing a cal, and I'm
not sure what is going on. Attached is a capture showing the correct
results (in Red), along with the incorrect results after my first two
attempts to perform a "short first" cal. Does anyone know what might be
happening?

I have no idea what I did wrong, but the procedure I now follow (which
seems to work, but probably has more steps than it needs to) is:

1. Reset CAL using the NanoVNA's LCD cal menu.
2. Invoke CAL on the NanoVNASharp app.
3. Perform the cal routine, starting with SHORT.
4. When Cal is finished, Save to 0 (still via the NanoVNASharp).

Also, a couple of times my LCD went WHITE while performing CALs via the
NanoVNASharp app, and it required a power-cycle to bring back.

- Jeff, k6jca

For anyone interested in brushing up on their Python skills, there are
many "free" courses available on Udemy if you know where to look. When
new courses are offered to the service, a percentage of them are offered
for free as "marketing". Normally this information was only available to
students of those instructors or services. There is a website called
"discudemy.com" that curates these courses by language. You will need to
first create an Udemy account if you don't already have one so they can
be saved to your account. Note the courses are available for a limited
time or until they run out. You want to locate the courses that have a
price associated to them and are they marked down to $0. These are
usually the full course. Courses without a price are usually "intros"
with little content but worth a look as it may be a new instructor. Also
look at the reviews.

Steps:

Create an Udemy account

Goto discudemy.com and choose your language then search for a topic

There are normally several pages. The front page is current, back pages
may be "expired" offerings.

Happy Hunting!

73, Vince

On 8/27/19 10:18 AM, Jeff Anderson wrote:

Jerry, thank you very much for the link to the paper by Thomas Baier.

I'm glad to see that Dick's and Thomas Baier's results are the same.
Always a good test!

Some years ago I took a short MOOC (massive open on-line course) on

Python, but I haven't used it since, and thus much of what I picked up as
leaked out since then.

I use Matlab a bit more often, so I've retained more of its

idiosyncrasies -- it can be very useful for these sorts of calculations,
and handles complex numbers easily.

Best,

Jeff, k6jca