Thanks for the info. I am only interested in frequencies up to 60 mHz (typical ham radio stuff on HF bands). I¡¯ll have to order those 805 surface mount resistors. I have some old-school metal film leaded 100 ohm resistors¡ª maybe I could use those if I trim the leads very short?
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Re: #buying NanoVNA models with MAX2870/MAX2871 PLL
#buying
sure the board may be different ... (its a new design)
i was asking if theoretically that could be done
happy coding and have a nice day
dg9bfc sigi
Am 22.03.2023 um 18:55 schrieb DiSlord:
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No, LiteVNA use different board
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Re: #buying NanoVNA models with MAX2870/MAX2871 PLL
#buying
No, LiteVNA use different board
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Re: #buying NanoVNA models with MAX2870/MAX2871 PLL
#buying
can one use a v2 hw and replace the pll chip (and use lite fw)?? are they pin compatible??
just thinking if i could replace that pll chip only (bridge performace and channel isolation is a different beast)
dg9bfc sigi
Am 21.03.2023 um 19:00 schrieb DiSlord:
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Compared to the attached diagram, I always calculate the amplification as
Amplificateion = Vs/E
is this the case for S21 or is the result of : Vs/Ve
I don't think it gives the same value
--
F1AMM
Fran?ois
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-----Message d'origine----- De la part de Jim Lux Envoy¨¦ : mercredi 22 mars 2023 18:08
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On 3/22/23 9:33 AM, Fran?ois wrote: S21 is typically given in dB magnitude plus phase, so gain would be 10^(mag/20).. If you have S21 as a linear complex value, then the gain is just the magnitude sqrt(a^2 + b^2). Phase is atan(b/a) Thank you but I want to start from the values in the .s2p file
Starting from a .s2p file coming out of nanovana-saver, I have for example
211618 -0.6282719521724260 0.48020111742544200 0.48752110556607600 0.50280646366029200 0 0 0 0
I would assume that S21 is the pair starting with 0.487.. and 0.5028... one thing that is important is to check the header of the .s2p and see whether it is giving you data in dB and degrees, or as complex linear. It seems to me that A priori, S21 is what is in yellow The image isn't readable (.wmz and .mso files?) - the png is just the equation for S11 in terms of impedance. The marker for this frequency tells me
S21 Polar 0.72 v 44.62¡ã That must be linear magnitude and phase, not dB. I calculate the magnitude as around 0.7 (see below) and that would be -3dB if converted to dB. sqrt(0.485^2 + 0.5028^2) is about 0.70 atan2 (0.485, 0.5028) is about 45.9 So that's pretty close (is it possible that the cursor is pointing at the point "next" to the one in the .s2p, or is it currently sweeping, so you're seeing the sweep to sweep variation). (the angle is close to 45 degrees, if x and y were swapped you get 44.1 degrees, but since the imaginary part is bigger than the real part, the angle must be >45) How to recalculate this value from the S21 (and S11 ?)
I know how to recalculate Z=A+jB from -0.6282719521724260 0.48020111742544200
We start from the fact that
I want to do the same for gain
Gain is 0.70
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NanoVNA s2p file contain:
frequency S11 S21 S12 S22
211618 -0.6282719521724260 0.48020111742544200 0.48752110556607600 0.50280646366029200 0 0 0 0
But this depend from snp file format see specification:
Also see this formulas used by NanoVNA in calculations
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S21 is typically given in dB magnitude plus phase, so gain would be 10^(mag/20).. If you have S21 as a linear complex value, then the gain is just the magnitude sqrt(a^2 + b^2). Phase is atan(b/a) Thank you but I want to start from the values in the .s2p file Starting from a .s2p file coming out of nanovana-saver, I have for example 211618 -0.6282719521724260 0.48020111742544200 0.48752110556607600 0.50280646366029200 0 0 0 0 It seems to me that A priori, S21 is what is in yellow The marker for this frequency tells me S21 Polar 0.72 v 44.62¡ã How to recalculate this value from the S21 (and S11 ?) I know how to recalculate Z=A+jB from -0.6282719521724260 0.48020111742544200 We start from the fact that I want to do the same for gain -- Fran?ois -----Message d'origine----- De la part de Jim Lux Envoy¨¦ : mercredi 22 mars 2023 17:12
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On 3/22/23 8:37 AM, Fran?ois wrote: Hello
I succeeded in establishing the formulas to pass from the parameter S11 (a+jb) to the true impedance (not reduced) Z=A+jB
I would like to find the gain (linear, not in dB) from the S21 parameter (a+jB).
Can you help me S21 is typically given in dB magnitude plus phase, so gain would be 10^(mag/20).. If you have S21 as a linear complex value, then the gain is just the magnitude sqrt(a^2 + b^2). Phase is atan(b/a)
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Hello
I succeeded in establishing the formulas to pass from the parameter S11 (a+jb) to the true impedance (not reduced) Z=A+jB
I would like to find the gain (linear, not in dB) from the S21 parameter (a+jB).
Can you help me
--
Fran?ois
F1AMM
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I use this calibration setup:
and for measuring the DUT:
Op wo 22 mrt 2023 om 15:50 schreef Doug <jdkearney@...>:
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One picture would be worth a thousand words.
Thanks, Doug, VA3DKA
On 22/03/2023 08:06, Donald S Brant Jr wrote:
On Tue, Mar 21, 2023 at 07:40 PM, Steve Johnson wrote:
@Donald, I don't understand this 180 degree positioning. Would that be
end-to-end? How much spacing (in mm) between them?
Yes, end to end at the end of your transmission line, the free ends going to a ground plane surrounding the end of the line.
Think of a baseball diamond, the transmission line runs from home base to the pitcher's mound; the resistors point from there to first and third
base, the grass is your ground.
I build them into the connector; I put them directly across the
connector with the resistors going from center conductor to ground. Make a
short by soldering a piece of shim stock across the connector, with a hole
to solder the center conductor. Use an open connector with the center
conductor cut flush for the open circuit.
73, Don N2VGU
--
*/If you forward this email, please delete the forwarding history which
also includes my email address. When sending emails, please BCC so as to
hide all addresses. Thanks for helping to prevent Scammers and Spammers
from mining addresses and spreading viruses./
73
Doug Kearney, VA3DKA
*
*Ottawa, ON *
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One picture would be worth a thousand words.
Thanks,? Doug, VA3DKA
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On 22/03/2023 08:06, Donald S Brant Jr wrote: On Tue, Mar 21, 2023 at 07:40 PM, Steve Johnson wrote:
@Donald, I don't understand this 180 degree positioning. Would that be
end-to-end? How much spacing (in mm) between them?
Yes, end to end at the end of your transmission line, the free ends going to a ground plane surrounding the end of the line.
Think of a baseball diamond, the transmission line runs from home base to the pitcher's mound; the resistors point from there to first and third base, the grass is your ground.
I build them into the connector; I put them directly across the connector with the resistors going from center conductor to ground. Make a short by soldering a piece of shim stock across the connector, with a hole to solder the center conductor. Use an open connector with the center conductor cut flush for the open circuit.
73, Don N2VGU
-- */If you forward this email, please delete the forwarding history which also includes my email address. When sending emails, please BCC so as to hide all addresses. Thanks for helping to prevent Scammers and Spammers from mining addresses and spreading viruses./ 73 Doug Kearney, VA3DKA * *Ottawa, ON *
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Whooops...installed TinySA firmware on NanoVNA
#firmware
I was meaning to update firmware on my TinySA. Thought I had TinySA plugged in, when it was actually the NanoVNA. The firmware update did work, but not sure I have two working TinySA's...lol.
I shutdown ST32Programmer and started DfuSE Demo. I placed the NANOVNA in DFU mode, and while Windows does see it in Device Manager, DfuSE does not see it as an Available device.
I went to the firmware site and see both a DFU file as well as a BIN file are available. What the heck, I'll try it. I used ST32Programmer and loaded the NanoVNA BIN file and it seems to be back to normal.
Is there anything I need to check other than calibration? So if this worked, I can use ST32Programmer across both devices and stop using DfuSE Demo?
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On Tue, Mar 21, 2023 at 07:40 PM, Steve Johnson wrote:
@Donald, I don't understand this 180 degree positioning. Would that be
end-to-end? How much spacing (in mm) between them?
Yes, end to end at the end of your transmission line, the free ends going to a ground plane surrounding the end of the line. Think of a baseball diamond, the transmission line runs from home base to the pitcher's mound; the resistors point from there to first and third base, the grass is your ground. I build them into the connector; I put them directly across the connector with the resistors going from center conductor to ground. Make a short by soldering a piece of shim stock across the connector, with a hole to solder the center conductor. Use an open connector with the center conductor cut flush for the open circuit. 73, Don N2VGU
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On Tue, Mar 21, 2023 at 04:40 PM, Steve Johnson wrote:
1. @Roger do you have a photo of your S21 jig? (By the way, I initially
thought your S11 jig was copper sheet with a non-conductive backing board to
attach the copper sheet to -- instead you clarified it is copper-clad PCB.
Same idea I guess, but on a different scale.)
I do not have a photo of my S21 jig. Basically it is a 50 ohm strip line with SMA connectors on both ends. The stripline has a break in the middle. Pin jacks near the center are used to accept the S11 cal loads and for the S21 through and isolation. It works well into the hundreds of MHz. A better design will use multiple identical boards with soldered on resistors. 2. @Roger - how will you make the > < V's you mentioned? I assume the points
of the V's won't touch, but will be close to each other. Does the point need
to be centered vertically or could one surface just be cut down with the
corner of a file to a sort-of V shape? I will use a PCB layout. Easy to do and much nicer to work with. The purpose of the V arrangement is to reduce the capacitance between the two sides. Right now it is a little less than 1 pF. Attached is a poor mockup of what the improved board will look like. The layout for the Short, Open and Load is the same on both sides. What is not shown is multiple vias from one side to the other to connect the two sides together. SMD resistors are installed on Load board. Short board will use a couple of 0 ohm resistors or a shorting bridge. Note that this jig is only useful up to 60 MHz. or so from my previous tests. There is quite an impedance bump due to the BNC to binding posts that has an effect at higher frequencies. I only use this for testing bigger components. For SMD parts I use another pin jack jig which works at much higher frequencies. 3. @Donald, I don't understand this 180 degree positioning. Would that be
end-to-end? How much spacing (in mm) between them?
The position and spacing of the resistors is not critical at the frequencies used by this simple jig. The inductance of the 0805 resistors is only a fraction of a nH and there is already considerable inductance on the copper board connecting the binding posts anyway. Attached are a couple of plots made with this jig. One is a resistor they measured 557 ohms @ DC and the other is a ceramic cap marked 68 pF. Roger
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Comments relating to recent posts:
1. @Roger do you have a photo of your S21 jig? (By the way, I initially thought your S11 jig was copper sheet with a non-conductive backing board to attach the copper sheet to -- instead you clarified it is copper-clad PCB. Same idea I guess, but on a different scale.)
2. @Roger - how will you make the > < V's you mentioned? I assume the points of the V's won't touch, but will be close to each other. Does the point need to be centered vertically or could one surface just be cut down with the corner of a file to a sort-of V shape?
3. @Donald, I don't understand this 180 degree positioning. Would that be end-to-end? How much spacing (in mm) between them?
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On Tue, Mar 21, 2023 at 09:56 AM, Jim Lux wrote:
I think you meant 90 degrees apart...Either way, we're talking nanohenries.
No, I meant 180. 1nanoHenry at 450MHz is 2.83¦¸, which is fairly significant. 0.19¦¸ at 3.0MHz. It all depends on your frequency and your application. 73, Don N2VGU
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See the Absolute Beginners Guide in the Files section of this group.
Roger
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Hi again. Can you help me with this:
I have set stimulus for resonance, between a set of frequencies, and it works ok, but, I am getting confused how to save it, after switching of !
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Donald S Brant Jr
Roger Need
