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Dislord NanoVNA v1.0.39

Is there a rundown of the new menu features added in firmware version 1.0.39? Ive listed what and where they are in the menu. Interested in what they are used for. Also my Nano VNA H4 does not have a serial connection or memory card slot. Are these modifications I can make?

-Display
-Transform
-More
-Q Factor
-Bandwidth
-4000Hz
-2000Hz
-1000Hz
-300Hz
-100Hz
-30Hz

-Marker
-Select Marker
-Marker 1
-Marker 2
-Marker 3
-Marker 4
-All Off
-Delta
-Search
-Maximum
-Minimum
-Search Left
-Search Right
-Tracking
-Operations
-Start
-Stop
-Center
-Span
-EDelay
-Smith Value
-Displays various smith values

-Stimulus
-Start
-Stop
-Center
-Span
-CW Freq
-Pause Sweep

-Calibrate
-Power
-Auto
-2 mA
-4 mA
-6 mA

The serial connection is for serial over Bluetooth using a Bluetooth module
like the HC-05. If you look at the schematic (
)
you will see P3 which is where you would connect a Bluetooth module. I
don’t know the process for modifying it for an micro sd card slot but you
should be able to find out by search the groups.io

On Sun, Nov 15, 2020 at 2:09 PM <markb.6180@...> wrote:

Dislord NanoVNA v1.0.39

Is there a rundown of the new menu features added in firmware version
1.0.39? Ive listed what and where they are in the menu. Interested in what
they are used for. Also my Nano VNA H4 does not have a serial connection or
memory card slot. Are these modifications I can make?

-Display
-Transform
-More
-Q Factor
-Bandwidth
-4000Hz
-2000Hz
-1000Hz
-300Hz
-100Hz
-30Hz

-Marker
-Select Marker
-Marker 1
-Marker 2
-Marker 3
-Marker 4
-All Off
-Delta
-Search
-Maximum
-Minimum
-Search Left
-Search Right
-Tracking
-Operations
-Start
-Stop
-Center
-Span
-EDelay
-Smith Value
-Displays various smith values

-Stimulus
-Start
-Stop
-Center
-Span
-CW Freq
-Pause Sweep

-Calibrate
-Power
-Auto
-2 mA
-4 mA
-6 mA





--

73,
Tripp Sanders
K5TRP

-bandwidth
Allow get less noise measure (but need more time) less value - less noise but longer

Power
Allow set output signal power (high power - more dynamic range, but can overload input)

SD card
NanoVNA allow SD card connection (some PCB on H have unsoldered, all H4 also have it)
It allow save screenshots (tap on bandwidth text at bottm for this) and tothstone (s1p and s2p) files to card

Connection
You can connect any serial module (Bluetooth to TTL / WiFi to TTL / USB to TTL) for control NanoVNA, this allow wireless get results on CPU (WiFi connection can reduce dynamoc range by increase noise floor)

About SD card read this post
/g/nanovna-users/message/14447

Is there a difference between:






*-Marker -Operations -Start -Stop
-Center -Span*
-EDelay

And





*-Stimulus -Start -Stop -Center -Span*
-CW Freq
-Pause Sweep


Does the Stimulus/Bandwidth and Calibrate/Power also affect the CW signal
bandwidth generated?

Stimulus - allow set sweep frequency range my set this values manually

Marker-Operations allow also set it, but from current marker data, example you have range 100M to 200M and current marker stay on 120M, if select Marker-Operations->Start you set Start frequency as 120M (current marker position) an so on.

Calibrate/Power also affect the CW signal?
Yes, more power setting, more output power in all modes.

Baindwidth - this measure signal setting, NanoVNAcan measure for example only 48 samples and calculate result, but can 480 samples, and get less noise result but need x10 time. More samples - allow measuere IF in less bandwidth range - get less noise at result.

May I ask a possibly stupid question?

I understand high-end professional vnas have a real bandwidth filter.

Our nanovnas have a bandwdth setting (on some firmwares -not V2 though), but is this by fft, or just the equivalent of averaging, which also has its own setting.

What is the effective difference between bandwidth and averaging? Both seem to reduce noise floor by a small amount, and slow down the sweep?

In what situations should you use one setting rather than the other (or both)?

Steve L. G7PSZ

Stephen,

I've always assumed that the filtering out of the fundamental or desired harmonic response was performed using a "classic" tapped delay-line digital filter. Assuming that noise is white noise (aka stochastic), then a reduction of bandwidth by ? reduces noise by 3dB, or if 2 sample are averaged, rather than considering a single sample, noise is again reduced by 3dB. In either case, the sweep speed is halved.

Reducing the bandwidth by half, with the same shape factor, would increase the filter's rejection of unwanted mixer products. It's not quite that simple, though, which is why it takes time and cunning to develop new versions of firmware.

So, yes, the nanoVNA has a "real" bandwidth filter in the firmware's signal processing.

HTH, 73, Stay Safe,

Robin, G8DQX

On 11/16/20 2:04 AM, Stephen Laurence wrote:

May I ask a possibly stupid question?
I understand high-end professional vnas have a real bandwidth filter.
Our nanovnas have a bandwdth setting (on some firmwares -not V2 though), but is this by fft, or just the equivalent of averaging, which also has its own setting.

A bunch of samples are acquired and then multiplied by sin/cos at a single frequency, and then summed. Essentially it's the same as a single bin of a Discrete Fourier Transform. Since there's no window, the effective filter shape is that for a rectangular pulse, i.e. sin(x)/x

What is the effective difference between bandwidth and averaging? Both seem to reduce noise floor by a small amount, and slow down the sweep?

Not a huge difference. Bandwidth affects a single measurement, averaging does multiple measurements over time. The latter should reduce noise by sqrt(N)

In what situations should you use one setting rather than the other (or both)?
Steve L. G7PSZ

On 11/16/20 6:22 AM, G8DQX list wrote:

Stephen,
I've always assumed that the filtering out of the fundamental or desired harmonic response was performed using a "classic" tapped delay-line digital filter. Assuming that noise is white noise (aka stochastic), then a reduction of bandwidth by ? reduces noise by 3dB, or if 2 sample are averaged, rather than considering a single sample, noise is again reduced by 3dB. In either case, the sweep speed is halved.
Reducing the bandwidth by half, with the same shape factor, would increase the filter's rejection of unwanted mixer products. It's not quite that simple, though, which is why it takes time and cunning to develop new versions of firmware.
So, yes, the nanoVNA has a "real" bandwidth filter in the firmware's signal processing.
HTH, 73, Stay Safe,
Robin, G8DQX
On 16/11/2020 10:04, Stephen Laurence wrote:

May I ask a possibly stupid question?

I understand high-end professional vnas have a real bandwidth filter.

Our nanovnas have a bandwdth setting (on some firmwares -not V2 though), but is this by fft, or just the equivalent of averaging, which also has its own setting.

What is the effective difference between bandwidth and averaging? Both seem to reduce noise floor by a small amount, and slow down the sweep?

In what situations should you use one setting rather than the other (or both)?

Steve L. G7PSZ

The actual filter code is this (from dsp.c). The table is 48 points with 4 or 5 cycles

static const int16_t sincos_tbl[48][2] = {
{ 10533, 31029 }, { 27246, 18205 }, { 32698, -2143 }, { 24636, -21605 },
{ 6393, -32138 }, {-14493, -29389 }, {-29389, -14493 }, {-32138, 6393 },
{-21605, 24636 }, { -2143, 32698 }, { 18205, 27246 }, { 31029, 10533 },
{ 31029, -10533 }, { 18205, -27246 }, { -2143, -32698 }, {-21605, -24636 },
{-32138, -6393 }, {-29389, 14493 }, {-14493, 29389 }, { 6393, 32138 },
{ 24636, 21605 }, { 32698, 2143 }, { 27246, -18205 }, { 10533, -31029 },
{-10533, -31029 }, {-27246, -18205 }, {-32698, 2143 }, {-24636, 21605 },
{ -6393, 32138 }, { 14493, 29389 }, { 29389, 14493 }, { 32138, -6393 },
{ 21605, -24636 }, { 2143, -32698 }, {-18205, -27246 }, {-31029, -10533 },
{-31029, 10533 }, {-18205, 27246 }, { 2143, 32698 }, { 21605, 24636 },
{ 32138, 6393 }, { 29389, -14493 }, { 14493, -29389 }, { -6393, -32138 },
{-24636, -21605 }, {-32698, -2143 }, {-27246, 18205 }, {-10533, 31029 }
};

static int32_t acc_samp_s;
static int32_t acc_samp_c;
static int32_t acc_ref_s;
static int32_t acc_ref_c;

void dsp_process(int16_t *capture, size_t length)
{
uint32_t *p = (uint32_t*)capture;
uint32_t len = length / 2;
uint32_t i;
int32_t samp_s = 0;
int32_t samp_c = 0;
int32_t ref_s = 0;
int32_t ref_c = 0;

for (i = 0; i < len; i++) {
uint32_t sr = *p++;
int16_t ref = sr & 0xffff;
int16_t smp = (sr>>16) & 0xffff;

int32_t s = sincos_tbl[i][0];
int32_t c = sincos_tbl[i][1];
samp_s += smp * s / 16;
samp_c += smp * c / 16;
ref_s += ref * s / 16;
ref_c += ref * c / 16;

}
acc_samp_s = samp_s;
acc_samp_c = samp_c;
acc_ref_s = ref_s;
acc_ref_c = ref_c;
}

Can anyone explain to me how to interpret all the figures displayed when the "L/C MATCH" tick-box is ticked under Display/Marker/Smith Value - and how it can be used?

On Wed, Dec 9, 2020 at 03:11 AM, Jacques - ZS1PL wrote:

Can anyone explain to me how to interpret all the figures displayed when the
"L/C MATCH" tick-box is ticked under Display/Marker/Smith Value - and how it
can be used?

This alalog of this calculator:


Allow compencate current impedance to 50Om

Thanks DiSlord!
It is a very nice FW version.