Can I put an attenuator into CH0 port for amplifier testing. I think 20-30dB is enough now.

Sure..

Do the cal with the attenuator in place

You won’t get as much dynamic range, but it will work.




> On Nov 20, 2023, at 2:32 AM, Leif M <leif.michaelsson@gmail.com> wrote:
>
>

> Can I put an attenuator into CH0 port for amplifier testing. I think
20-30dB is enough now.

_._,_._,_

* * *

You can lower the level of CH0 with the software. You can also put an
attenuator on CH0 but you should do the calibration with the attenuator.

> **envoy e :** 20 novembre 2023 a 09:33
> **de :** Leif M <leif.michaelsson@gmail.com>
> **a :** NanoVNAV2@groups.io
> **objet :** [nanovnav2] Lower output from S11 or CH0 port?

>

>
> Can I put an attenuator into CH0 port for amplifier testing. I think 20-30dB
is enough now.

_._,_._,_

* * *

"You can lower the level of CH0 with the software."
Interesting. Where is that setting? I have NanoVNA V2 Plus4, is it in  firmware or in  computer software. What is the range of adjustment?
"You can also put an attenuator on CH0 but you should do the calibration with the attenuator."
Sure.
But as Jim Lux says it will  work. Do I see a difference in S11 impedance readings that is, is there only two accurate numbers in results instead of three  or more? I  am  measuring amplifiers, and everything
is +-10%

you can put an attenuator on input of amp not to overload its input plus
attenuator on ch1 (s21) not to overload the vna

dg9bfc sigi

Am 20.11.2023 um 09:33 schrieb Leif M:

> Can I put an attenuator into CH0 port for amplifier testing. I think
> 20-30dB is enough now.
>

With the computer software... I never used this but I remember it is possible.
The range goes from -30 dBm to +10 dBm. The default value is -15 dBm. I have a
nanovna V2. Now, I don't modify the firmware because I loaded some firmwares
that didn't work well.

If the calibration is done with the attenuator, S11 is normally good but the
dynamic range is shorter.

I'm sorry but I don't understand "is there only two accurate numbers in
results instead of three or more?".

> **envoy e :** 20 novembre 2023 a 19:21
> **de :** Leif M <leif.michaelsson@gmail.com>
> **a :** NanoVNAV2@groups.io
> **objet :** Re: [nanovnav2] Lower output from S11 or CH0 port?

>

>
> "You can lower the level of CH0 with the software."
> Interesting. Where is that setting? I have NanoVNA V2 Plus4, is it in
firmware or in computer software. What is the range of adjustment?
> "You can also put an attenuator on CH0 but you should do the calibration
with the attenuator."
> Sure.
> But as Jim Lux says it will work. Do I see a difference in S11 impedance
readings that is, is there only two accurate numbers in results instead of
three or more? I am measuring amplifiers, and everything
> is +-10%

_._,_._,_

* * *

About the range from -30 dBm to +10 dBm, it is what is written on the computer
software but I have not checked. I can check it but I have not done yet...

> **envoy e :** 20 novembre 2023 a 19:21
> **de :** Leif M <leif.michaelsson@gmail.com>
> **a :** NanoVNAV2@groups.io
> **objet :** Re: [nanovnav2] Lower output from S11 or CH0 port?

>

>
> "You can lower the level of CH0 with the software."
> Interesting. Where is that setting? I have NanoVNA V2 Plus4, is it in
firmware or in computer software. What is the range of adjustment?
> "You can also put an attenuator on CH0 but you should do the calibration
with the attenuator."
> Sure.
> But as Jim Lux says it will work. Do I see a difference in S11 impedance
readings that is, is there only two accurate numbers in results instead of
three or more? I am measuring amplifiers, and everything
> is +-10%

_._,_._,_

* * *

"I'm sorry but I don't understand "is there only two accurate numbers in results instead of three or more?".I  wonder what is meant when people say that dynamic range is less. Are results less accurate, for example if resistance is 5.12345 ohms, only first (5) digit is correct. I wonder if high and low impedances are less accurate with attenuator on CH0 channel.

"With the computer software... I never used this but I remember it is possible. The range goes from -30 dBm to +10 dBm. The default value is -15 dBm. I have a nanovna V2. Now, I don't modify the firmware because I loaded some firmwares that didn't work well." I  have to check that.

When the measurement dynamic range is reduced (by inserting an
attenuator), the signals being measured are lower, closer to the
instrument's own noise. As the desired signal gets closer to the noise,
the measurements will include more noise, and thus have a larger random
component. If you measure many times you'll see different values,
distributed about an average. So, yes, while many digits may be
displayed, the number of significant figures in the result decreases.
Instead of having a result 5.123, plus or minus 0.002, you might have
5.1, plus or minus 0.3. VNAs do not do a propagation of errors
calculation, but you could create a spreadsheet to do this.

Decreasing the measurement bandwidth or averaging many measurements can
help reduce the amount of randomness in the measurements.

On 2023-11-21 21:59, Leif M wrote:

> "I'm sorry but I don't understand "is there only two accurate numbers in results instead of three or more?".I wonder what is meant when people say that dynamic range is less. Are results less accurate, for example if resistance is 5.12345 ohms, only first (5) digit is correct. I wonder if high and low impedances are less accurate with attenuator on CH0 channel.
>
> "With the computer software... I never used this but I remember it is possible. The range goes from -30 dBm to +10 dBm. The default value is -15 dBm. I have a nanovna V2. Now, I don't modify the firmware because I loaded some firmwares that didn't work well." I have to check that.
>
>


Links:
------
[1] https://groups.io/g/NanoVNAV2/message/4471
[2] https://groups.io/mt/102704965/389967
[3] https://groups.io/g/NanoVNAV2/post
[4] https://groups.io/g/NanoVNAV2/editsub/389967
[5] https://groups.io/g/NanoVNAV2/leave/10834803/389967/1541401465/xyzzy

I'll address the dynamic range question. Take visible light. Place
yourself in a small room with no windows and the door closed. It's dark.
You can't see much if anything. Now turn on a small flashlight you just
happen to have in your pocket. Now you can see the room, the walls, the
ceiling and floor and anything that happen to be in the room. This might
represent no attenuator case. You have gone from absolutely dark without
being able to see anything to being able to see the room, although dimly.

Now open the door or window. The room becomes bright, but the little
flashlight has absolutely no effect. You may not even be able to see the
flashlight is on. This might represent a weak "signal" with an attenuator
attached. You have lost dynamic range between dark and light. All you're
left with the the brightly lit room.

Dave - WØLEV

On Wed, Nov 22, 2023 at 1:30 PM Leif M <leif.michaelsson@gmail.com> wrote:

> "I'm sorry but I don't understand "is there only two accurate numbers in
> results instead of three or more?".I wonder what is meant when people say
> that dynamic range is less. Are results less accurate, for example if
> resistance is 5.12345 ohms, only first (5) digit is correct. I wonder if
> high and low impedances are less accurate with attenuator on CH0 channel.
>
> "With the computer software... I never used this but I remember it is
> possible. The range goes from -30 dBm to +10 dBm. The default value is -15
> dBm. I have a nanovna V2. Now, I don't modify the firmware because I loaded
> some firmwares that didn't work well." I have to check that.
>
>
>

--

*Dave - WØLEV*

SIGNIFICANT FIGURES in a MEASUREMENT:

Suppose you measure the diameter of a circle at 2.75-feet. That is 2 and
3/4 feet in diameter. Then to calculate the circumference of that circle,
one must multiply by pi (basic remedial geometry) . Grab your handy-dandy
HP (yes, RPN) calculator. The HP calculator stores constants like pi to 14
decimal places but displays a maximum of eleven decimal places if you set
that option (ALL on my 35S): 3.14159265359. Now multiply that by your
measurement of the diameter of your circle: 2.75-feet. Answer: The
circumference of your circle is 8.63937979737-feet. Glory be! We now have
the circumference of the circle to 11, yes, eleven decimal places! Better
contact NIST in Boulder for precision length measuements. Can you measure
the diameter that accurately with your ruler? Why, we have gone from two,
2, significant decimals to eleven, 11 places. Why, we have generated such
impeccable accuracy from only two original significant decimals! Better
patent that operation, and quickly!!! Don't forget NIST.....

You started with only two decimal places. You don't have any more accuracy
than two, 2, significant decimals! You can't generate more accuracy than
you started with!

With RF measurements in dB, I seriously doubt the average amateur, even
using the wonderful NANOVNAs and TinySAs, can do better than two decimal
places in any measurement. Even measuring resistance with a good DMM, five
or greater decimal places? I seriously doubt it!!

Further: Since most of us just ate the traditional turkey dinner for
Thanksgiving, I'll offer another analogy. It's like placing one stuffed
turkey in the oven and when it's done, you now have ten, 10, turkeys to
remove from the oven. We just violated one of the very basic rules of hard
science: generating something from nothing. Can't be done.

Dave - WØLEV



On Fri, Nov 24, 2023 at 3:29 AM W0LEV via groups.io <davearea51a=
gmail.com@groups.io> wrote:

> I'll address the dynamic range question. Take visible light. Place
> yourself in a small room with no windows and the door closed. It's dark.
> You can't see much if anything. Now turn on a small flashlight you just
> happen to have in your pocket. Now you can see the room, the walls, the
> ceiling and floor and anything that happen to be in the room. This might
> represent no attenuator case. You have gone from absolutely dark without
> being able to see anything to being able to see the room, although dimly.
>
> Now open the door or window. The room becomes bright, but the little
> flashlight has absolutely no effect. You may not even be able to see the
> flashlight is on. This might represent a weak "signal" with an attenuator
> attached. You have lost dynamic range between dark and light. All you're
> left with the the brightly lit room.
>
> Dave - WØLEV
>
> On Wed, Nov 22, 2023 at 1:30 PM Leif M <leif.michaelsson@gmail.com> wrote:
>
>> "I'm sorry but I don't understand "is there only two accurate numbers in
>> results instead of three or more?".I wonder what is meant when people say
>> that dynamic range is less. Are results less accurate, for example if
>> resistance is 5.12345 ohms, only first (5) digit is correct. I wonder if
>> high and low impedances are less accurate with attenuator on CH0 channel.
>>
>> "With the computer software... I never used this but I remember it is
>> possible. The range goes from -30 dBm to +10 dBm. The default value is -15
>> dBm. I have a nanovna V2. Now, I don't modify the firmware because I loaded
>> some firmwares that didn't work well." I have to check that.
>>
>>
>
> --
>
> *Dave - WØLEV*
>
>
>
>
>

--

*Dave - WØLEV*

Dave.
Thank you for the wonderful and humerous way you replied. It brought a smile to my face, and a very very BIG one.  I double love the way you suggested patenting this great new invention.  It truly can be described as getting more for less ??? <Smile>.
Keep up the good work Dave.
Albert
EI7II.

Hmmm... What if i measure those 2,75 feet... Not with a ruler but more precise

2,75000000000 feet?!? Hmm??

Dg9bfc sigi



Am 24.11.2023 17:47 schrieb W0LEV <davearea51a@gmail.com>:

> SIGNIFICANT FIGURES in a MEASUREMENT:

>

>
>

>

> Suppose you measure the diameter of a circle at 2.75-feet. That is 2 and 3/4
feet in diameter. Then to calculate the circumference of that circle, one must
multiply by pi (basic remedial geometry) . Grab your handy-dandy HP (yes, RPN)
calculator. The HP calculator stores constants like pi to 14 decimal places
but displays a maximum of eleven decimal places if you set that option (ALL on
my 35S): 3.14159265359. Now multiply that by your measurement of the diameter
of your circle: 2.75-feet. Answer: The circumference of your circle is
8.63937979737-feet. Glory be! We now have the circumference of the circle to
11, yes, eleven decimal places! Better contact NIST in Boulder for precision
length measuements. Can you measure the diameter that accurately with your
ruler? Why, we have gone from two, 2, significant decimals to eleven, 11
places. Why, we have generated such impeccable accuracy from only two original
significant decimals! Better patent that operation, and quickly!!! Don't
forget NIST.....
>

>

>
>

>

> You started with only two decimal places. You don't have any more accuracy
than two, 2, significant decimals! You can't generate more accuracy than you
started with!

>

>
>

>

> With RF measurements in dB, I seriously doubt the average amateur, even
using the wonderful NANOVNAs and TinySAs, can do better than two decimal
places in any measurement. Even measuring resistance with a good DMM, five or
greater decimal places? I seriously doubt it!!

>

>
>

>

> Further: Since most of us just ate the traditional turkey dinner for
Thanksgiving, I'll offer another analogy. It's like placing one stuffed turkey
in the oven and when it's done, you now have ten, 10, turkeys to remove from
the oven. We just violated one of the very basic rules of hard science:
generating something from nothing. Can't be done.
>

>

>
>

>

> Dave - WØLEV
>

>

>
>

>

>
>

>

>
>

>

> On Fri, Nov 24, 2023 at 3:29 AM W0LEV via [groups.io](http://groups.io)
<davearea51a=[gmail.com@groups.io](mailto:gmail.com@groups.io)> wrote:
>

>

>> I'll address the dynamic range question. Take visible light. Place yourself
in a small room with no windows and the door closed. It's dark. You can't see
much if anything. Now turn on a small flashlight you just happen to have in
your pocket. Now you can see the room, the walls, the ceiling and floor and
anything that happen to be in the room. This might represent no attenuator
case. You have gone from absolutely dark without being able to see anything to
being able to see the room, although dimly.
>

>>

>>
>

>>

>> Now open the door or window. The room becomes bright, but the little
flashlight has absolutely no effect. You may not even be able to see the
flashlight is on. This might represent a weak "signal" with an attenuator
attached. You have lost dynamic range between dark and light. All you're left
with the the brightly lit room.

>>

>>
>

>>

>> Dave - WØLEV
>

>>

>>
>

>>

>> On Wed, Nov 22, 2023 at 1:30 PM Leif M
<[leif.michaelsson@gmail.com](mailto:leif.michaelsson@gmail.com)> wrote:
>

>>

>>> "I'm sorry but I don't understand "is there only two accurate numbers in
results instead of three or more?".I wonder what is meant when people say that
dynamic range is less. Are results less accurate, for example if resistance is
5.12345 ohms, only first (5) digit is correct. I wonder if high and low
impedances are less accurate with attenuator on CH0 channel.
>
> "With the computer software... I never used this but I remember it is
possible. The range goes from -30 dBm to +10 dBm. The default value is -15
dBm. I have a nanovna V2. Now, I don't modify the firmware because I loaded
some firmwares that didn't work well." I have to check that.

>>

>>
>
> \--
>

>>

>> **Dave - WØLEV
> **

>>

>>
>

>>

>>
>

>

>
>
> \--
>

>

> **Dave - WØLEV
> **

>

>
>

>

>
>



_._,_._,_

* * *