开云体育

I'm trying to add an on-demand scan command and I'm using cmd_scan (already present in the firmware) as a template.
However cmd_scan causes the firmware to hang.
If I add a lot of printf statements it will scan but very slow
Someone aware why?

An interesting read. Yet another approach.

I agree on saving calibrations! The current development branch now has full
SOLT(I) calibration, and I'll try to get saving/loading in before releasing
0.0.5

--
Rune

Hi Rune --

Yes, I had done a sweep before the "short" calibration, but not the other two.

It would be really nice if one could save a calibration to a file, so that he could recall the
file on later invocations of nanovnasaver instad of having to recalibrate for similar
runs every invocation.

73 --
Harry, W5PNY

On Wed, 4 Sep 2019 at 13:58, kb3cs <kb3cs@...> wrote:

the damage is caused by the power level, not the output impedance of the
HD1. it is just that simple.

- 3g (base 19) -

The marketing hype specifically says its the impedance, not the power
level.

I somewhat doubt any walkie talkie antenna would be damaged by 10 W of
power. Certainly, the ones I have seen are just basically a coil of wire,
with no matching components.

I would also be a bit concerned about 10 W of RF close to my eyes - the
part of the body most likely to be damaged by high levels of RF.

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892

Tel 01621-680100 / +44 1621-680100

i believe Google Translate is part of this conversation loop.

progress! your transceiver is a Retevis Ailunce HD1 VHF/UHF DMR handheld.

you report 3rd party antennas being damaged when used with this handheld.

you must first realize the typical handheld output power is 5W. the Ailunce HD1 output power is 1W or 10W (selectable).
it is no surprise to me 3rd party antennas are being damaged when the Ailunce HD1 is set to 10W out.

the damage is caused by the power level, not the output impedance of the HD1. it is just that simple.

- 3g (base 19) -

Gentlemen, many thanks for your help.

Python is now successfully installed and I can launch Rune's python code.

The issue was that Python wasn't on the path (as several suggested). Fixed by checking the appropriate box when installing Python 3.7.4.

I'm looking forward to playing with Rune's script when I return home.

Best,

- Jeff, k6jca

On Tue, 3 Sep 2019 at 19:18, Reginald Beardsley via Groups.Io
<pulaskite@...> wrote:

Please add the console RS-232 parameters:
9600 8N1 XON/XOFF
to the information above.

At least on Windows the console works at much higher rates than 9600.
I've been using it at 115200.
I also put much of this information in this thread in the wiki, which
may be a better place to keep track of the changes/current info than
an email thread.
Anyone can edit this page.

/g/nanovna-users/wiki/shellcommands

--buck

Attached is a comparison of Return Loss measurements for four different loads, at three different frequencies. Devices testing were two NanoVNAs, a Rigol Spectrum Analyzer/RF bridge, and an AAI Vector Impedance Analyzer. Tests were done at 50 MHz, 450 MHz, and 720 MHz. Data space is reserved for the third NanoVNA expected in a week or so.

WA8TOD

On Tue, 3 Sep 2019 at 09:36, -- <gpdxdveil@...> wrote:

I have 10W U/V transceiver.
Some of same transceiver users reports burnt after change 3rd party
antenna.
-'Don't use 50 Ohm matched aftermarket antenna. This transceiver not
matched 50 Ohm'
-'Burnt after even genuine Nagoya/Diamond antenna'

This sounds a combination of

1) Marketing rubbish to get you to use their antennas.

2) Poor engineering

The output impedance of this transmitter is likely to be considerably less
than 50 ohms. If the output impedance was 50 ohms and it connected to a 50
ohm antenna you would get maximum power transferred, but an efficiency of
only 50%.

The impedance of any antenna on a handheld transceiver will vary
*considerably* depending upon the position one holds it. So any handheld
device that is properly engineered will tolerate any degree of mismatch.

You would not be able to measure the output impedance of the transceiver
without a system called “load pull” If you connect the NanoVNA to the
output of the transceiver, would very quickly destroy the NanoVNA.

Depending on how much the transceiver cost, I think you should either

1) Throw it in the bin
2) Seek a refund.

Dave

-

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales.
Company number 08914892.
Registered office:
Stokes Hall Lodge,
Burnham Rd,
Althorne,
Chelmsford,
Essex,
CM3 6DT,
United Kingdom

Does changing optimisation level
(-O, -O2 etc) change the size of the code?

Yes; I suggest reading this:


It is generally easier to find latest versions of gcc cross-compile
toolkits pre-built
for e.g. Linux, and Solaris 10 x86 is no longer supported by recent GCC:

On Wed, 4 Sep 2019 at 02:19, Vince Rooney <vince@...> wrote:

I'm doing a little research on this issue with not having enough space
on the chip. From what I can make out in this thread, the firmware is
using ChibiStudio which uses gcc as it's base compiler. The thing is,
gcc does not optimize the code for the ARM fully compared to ADS (Arm
Development Studio). The problem is their programs are expensive. I've
written to them to see if there is a free community version.

Just a couple of thoughts about gcc. Is debugging information saved with
-g? That will make the executable larger. Does changing optimisation level
(-O, -O2 etc) change the size of the code? Would building with gcc work
any better on another platform? I have here gcc on Solaris x86. I have a
Soarsris 10 SPARC - I think I installed gcc on that, but if not it could be
done. I will check later today.

I don’t run Windows here. I hope that it not going to cause any problems
updating the code.

Dave
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales.
Company number 08914892.
Registered office:
Stokes Hall Lodge,
Burnham Rd,
Althorne,
Chelmsford,
Essex,
CM3 6DT,
United Kingdom

As a matter of interest, should one get a power failure during the
“download” does that render the device useless or can one just restart the
process when power is restored?

My understanding is that STM32 DFU bootloader
is NOT overwritten by download process,
so that failures may be restarted/recovered.

There is a rather simple method
for measurement of an active device source impedance

Measuring nonlinear devices
(e.g. ferrite cores, diodes and active devices) can be problematic
with non-sinusoidal stimulation e.g. nanoVNA.
While nanoVNA DSP can sort harmonics,
DUT "sees" full stimulation.
Nonlinear DUT response at harmonic of interest
is confounded by amplitude of others,
unlike e.g. ideal transmission lines, capacitors, resistors and inductors.

Thanks for the insight...
Not good news as based on earlier messages I have ordered from TomTop and awaiting delivery :-(

TomTop does offer a refund if item(s) not received or not as ordered / damaged... Will be interesting to see if I take delivery and which version supplied.

In the meantime I continue to enjoy the discussions on this forum!

73 Nigel ZS6RN ex G8DEV

Right-clicking on the icon revealed the path, which, interestingly, is not visible if I do a search for python items on my c: drive.
The directory pointed to is: C:\Users\Jeff\AppData\Local\Programs\Python\Python37-32
If I look under C:\Users\Jeff, I do not see the AppData directory. Weird (at least, weird to a hw guy).

Windows filesystems have an attribute for hiding content, which some
malware exploits.
Yes weird, AKA "security by obscurity".
Here are procedures to "unhide" from file Explorer:

The reason for having in-app calibration rather than using the calibration
on the device is to avoid these problems. The in-app calibration supports
pretty much however many calibration points you're willing to wait for, and
it works by frequency, so you can change your span and still get reasonable
results.

I'm not a big fan of limiting users in what they do, so I'm certainly not
keen on implementing a limit on sweep count. But if it can be shown that
accuracy suffers with some settings, it might be prudent to add a warning.

Thanks for your input!
--
Rune / 5Q5R

On Wed, 4 Sep 2019 at 07:42, <erik@...> wrote:

A word of warning when using DfuSEDemo.exe
Uploading means downloading from the device into your computer
Upgrade/Verify is for loading new software into your device

So ALWAYS first do a "Upload" (e.g. a download) from your device into your
computer to create a backup of the firmware in a safe place
Then you can test new SW and restore to the old if needed.
I tested and the restore works!!!!

As a matter of interest, should one get a power failure during the
“download” does that render the device useless or can one just restart the
process when power is restored?

Dave
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales.
Company number 08914892.
Registered office:
Stokes Hall Lodge,
Burnham Rd,
Althorne,
Chelmsford,
Essex,
CM3 6DT,
United Kingdom

Currently NanoVNA has 4 calibration slots.
How about limit sweep count up to 4?
*User must calibrate done every 1/4 bandwidth then save 0 to 3 calibration slot.
*nanovna-saver loads every 1/4 bandwidth calibration slots prior to sweeps every 1/4 bandwidth.
It would be more static(?) results we get - Just I my 2 cent

Does not have NanoVNA or professional lab gears. Also I'm not RF expert too. But...
If lots of sweep count, calibrated data still acceptable/trustworthy?
ie) 1-800MHz /w 10x => sweep every 1/10 bandwidth. but calibrated full range(1-800MHz)