Re: Proper way to measure length of _Window_Line_?
Maybe after 78 years.
I think it¡¯s happening to me.
Ed McCann
AG6CX
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Zahi
Not sure why no one gave you the direct, easy answer. Chose the log mag display on your vna. That is return loss.
Ron
N4XD
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Re: Nano VNA-H won't start after battery died
Tnx Larry...
Em qui., 17 de fev. de 2022 14:28, Larry Rothman <nlroth@...>
escreveu:
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Your battery is defective - get a new one or have a look at some of my
early posts where I used a cellphone battery.
/g/nanovna-users/attachment/223/0/Battery-PCB-MiscShields.jpg
On Thursday, February 17, 2022, 11:50:19 a.m. EST, ARY SANTOS <
py2ary@...> wrote:
my nano vna Hugen v4 shows full battery but after about 10 seconds turn
off.... connected to USB port works fine
On Thu, Feb 17, 2022 at 10:35 AM Brady Nelson <tbradynelson@...>
wrote:
Hi All,
My Nano VNA-H will not turn on after charging. It had been sitting for a
while, so I assumed it was the dead battery, but after charging, the
battery is at a good voltage but the screen will not turn on. Doesn't want
to turn on via USB either. Any ideas what could be causing this?
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Re: Proper way to measure length of _Window_Line_?
I just threw out some 300 Ohm twin lead that was in a box of wire because it had deteriorated so much that the insulation cracked and pieces of it came off. That¡¯s what happens to it after probably 50 years.
Gary
W9TD
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Re: Proper way to measure length of _Window_Line_?
I have found 300 ohm twin lead at garage sales or hamfests, etc. after I used the remaining length I had. In 2006 I made about a dozen J antennas for the Empire State Games (NY state). They were used at the various venues all over the county.
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Re: Proper way to measure length of _Window_Line_?
On 2/20/22 4:27 PM, Dex W4DEX wrote: On Sun, Feb 20, 2022 at 5:12 PM WB2UAQ <pschuch@...> wrote:
Good luck finding 300 ohm twin lead in this day and age. Wireman has 300 ohm twin lead. I bought some about a year ago.
Maybe I'll just build some balanced line, or try some 100-120 ohm twisted pair.
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Re: Proper way to measure length of _Window_Line_?
On Sun, Feb 20, 2022 at 5:12 PM WB2UAQ <pschuch@...> wrote: Good luck finding 300 ohm twin lead in this day and age. Wireman has 300 ohm twin lead. I bought some about a year ago.
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Re: Proper way to measure length of _Window_Line_?
On Sun, Feb 20, 2022 at 02:11 PM, WB2UAQ wrote: Good luck finding 300 ohm twin lead in this day and age. I needed some for a project about a year ago, and wound up buying a roll of "vintage" Radio Shack twin lead on Ebay. Wasn't expecting that.
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Re: Proper way to measure length of _Window_Line_?
Good luck finding 300 ohm twin lead in this day and age. When I go to Lowe's and Home Depot or other stores that sold TV hardware, I don't see it any longer. There's plenty of RG-6 and OTA TV antenna hardware.
To measure the characteristics of balanced line I first find the freq where the line under test is a quarter wave long. I do this by connecting the line under test, with its far end shorted, across a 50 ohm load at the output of the balun (the terminals that were calibrated). I then sweep from the lowest frequency looking for the freq where the return loss is the highest. The return loss is often higher than 20 dB at this freq. The return loss is the highest at this freq because the shorted transmission line under test looks like a high impedance (parallel resonance) leaving the 50 ohm load hardly disturbed and having a pretty high RL. Next I remove the 50 ohm load from the test terminals and attach it to the far end of the transmission line under test. The impedance measured (Zin) by the Nano at the freq where the line is a quarter wave long should be resistive. Using the old Q section formula where Zo = (Zin x Zload)^0.5. Zload is the resistance placed at the far end of the transmission line under test.
For 300 ohm line, with Zload being a 50 ohm resistance, Zin should be a resistance of about 1800 ohms. Check: 300 = (50 x 1800)^0.5. Note that everything is a resistance which makes the math pretty easy not requiring complex algebra. ( on the Smith chart the resistances are 9 o'clock and 3 o'clock centered on Zo)
I have JSC twin lead myself. It is not the part number mentioned above. I think it is JSC 1018, spec'd to be 300 ohms. It looks like TV twin lead but it has 18 gauge stranded conductors. Years ago (like 15 to 18 yrs), using the above Q section formula the Z is not the nominal 300 ohms and came in at about 230 ohms. I wondered why this could be so I asked the mfr and never received a reply. I believe the usual TV 300 ohm line uses 22 gauge wire instead of 18 so the JSC 1018, made with the 18 didn't get its spacing adjusted wider to get Zo to be 300 ohms.
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Thanks, Roger. On Sun., 20 Feb. 2022 at 1:27 p.m., Roger Need via groups.io<sailtamarack@...> wrote: On Sun, Feb 20, 2022 at 07:55 AM, Larry Rothman wrote: The version 2 and newer Nanovnas use a binary command structure. I do not
think there is a document for them yet so you will have to go through the
open-source firmware to see those.?
? Larry - The SAA2 binary protocol is described in this document.... Roger
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Thanks Dave!
Joe WB9SBD /W9ET
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On 2/20/2022 2:05 PM, W0LEV wrote: You don't "need" the bottom of the chart which is -j50. Read your value
midband on the measured curve at 3.750 MHz (not critical).
Extreme right on the Smith Chart is an open while the extreme left is a
short - both on the horizontal line.
Dave - W?LEV
On Sun, Feb 20, 2022 at 7:48 PM Joe WB9SBD<nss@...> wrote:
oK,
UST TRIED WITH A STIMULUS SPAN OF 3.5 TO 4 MEG.
Oops cap lock, anyway.
The smith chart curve starts at the far right, short? or open? UG memory
again,,,
anyway the curve starts at the far right, but only curves down to say
the 4 to 5 o clock position it doesn't get to the bottom of the display.
so Now what?
Joe WB9SBD / W9ET
On 2/20/2022 12:20 PM, W0LEV wrote:
It's best to measure the capacitor at the frequency of interest, especially
as that frequency increases. For a "sticker value", use a low frequency -
1 MHz or less. As the frequency increases, parasitic inductance becomes
more and more evident which cancels some of the effective capacitance.
Dave - W?LEV
On Sun, Feb 20, 2022 at 2:52 PM Joe WB9SBD<nss@...> wrote:
What is a typical stimulus range for measuring a Cap?
If it makes any difference it is a 500pf cap, and is used between 3.5
and 4 Mhz.
Should I set the stimulus rage for those values?
And the measurement should be taken when the smith chart tracer thing is
right at the bottom like 6 O'clock position correct?
Joe WB9SBD / W9ET
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You don't "need" the bottom of the chart which is -j50. Read your value
midband on the measured curve at 3.750 MHz (not critical).
Extreme right on the Smith Chart is an open while the extreme left is a
short - both on the horizontal line.
Dave - W?LEV
toggle quoted message
Show quoted text
On Sun, Feb 20, 2022 at 7:48 PM Joe WB9SBD <nss@...> wrote: oK,
UST TRIED WITH A STIMULUS SPAN OF 3.5 TO 4 MEG.
Oops cap lock, anyway.
The smith chart curve starts at the far right, short? or open? UG memory
again,,,
anyway the curve starts at the far right, but only curves down to say
the 4 to 5 o clock position it doesn't get to the bottom of the display.
so Now what?
Joe WB9SBD / W9ET
On 2/20/2022 12:20 PM, W0LEV wrote:
It's best to measure the capacitor at the frequency of interest, especially
as that frequency increases. For a "sticker value", use a low frequency -
1 MHz or less. As the frequency increases, parasitic inductance becomes
more and more evident which cancels some of the effective capacitance.
Dave - W?LEV
On Sun, Feb 20, 2022 at 2:52 PM Joe WB9SBD<nss@...> wrote:
What is a typical stimulus range for measuring a Cap?
If it makes any difference it is a 500pf cap, and is used between 3.5
and 4 Mhz.
Should I set the stimulus rage for those values?
And the measurement should be taken when the smith chart tracer thing is
right at the bottom like 6 O'clock position correct?
Joe WB9SBD / W9ET
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Re: NanoSaver on ubuntu- mint
No, if I plug the USB cable from the NanoVNA to the PC and push the icon to open the NanoSaver software, NOT open up. If I unplug the USB cable the NanoSaver open up, I select SCAN Refresh and NOT see the NanoVNA serial port. *Sent:* Sunday, February 20, 2022 at 6:16 PM *From:* "Dragan Milivojevic" <d.milivojevic@...> *To:* [email protected]*Subject:* Re: [nanovna-users] NanoSaver on ubuntu- mint I'm sorry, I do not understand what you are trying to say. You expect for NanoVNASaver to start on its own when you plug in the NanoVNA?
On Sun, 20 Feb 2022 at 11:37, Francesco <realfran@...> wrote: Yes, I install libreVNA with is on software and work, I cheek on
Mint/Ubuntu and give me the list of usb ports, I plug the NanoVNA and give
me the Cypress USB driver is installed, *I give more detall* : when I plug
the USB cable from the NanoVNA the Saver software not open, when I unplug
the cable open up, the problem is NanoSaver software don't open the USB
port.
I tray to put this information on the terminal but not result.
One other information I never use software terminal on my life.
Thank you for the help the only think I doing is "copy and past on the
terminal".
Best regards.
Francesco.
*Sent:* Sunday, February 20, 2022 at 3:39 AM
*From:* "Dragan Milivojevic" <d.milivojevic@...>
*To:* [email protected]
*Subject:* Re: [nanovna-users] NanoSaver on ubuntu- mint
AFAIK Saver does not support LibreVNA
On Sat, 19 Feb 2022 at 10:24, Francesco <realfran@...> wrote:
Hello, I install LibreVNA and work, I use the USB port for different
device and work, the only problem is NanoVNA-Saver is installed but not
find the the serial/usb device.
*Sent:* Saturday, February 19, 2022 at 4:36 AM
*From:* "Dragan Milivojevic" <d.milivojevic@...>
*To:* [email protected]
*Subject:* Re: [nanovna-users] NanoSaver on ubuntu- mint
On Sat, 19 Feb 2022 at 01:22, Francesco <realfran@...> wrote:
Hello, I set up one laptop with Mint Linux "cinnamon" I install NanoVNA
Saver I don't find the "device port" get a problem with the LiteVNA and the
NanoVNA V2 plus4.
Please some help, I'm computer illiterate and this is the first time I use
Linux (I'm lost) I install a lot of Python libraries and I get confused
with the " CONSOLE "
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Even easier, there's a command line way to get to any of the NanoVNA flavors, using NanoVNA-Saver. See this post from the nanovnav2 list: /g/NanoVNAV2/message/3001Many thanks Jim This is precisely what I was looking for. Additionally I found a purpose built Python script by Kevin O'Brien which offers a command line interface --- works when placed in the NanoVNA directory. Thanks again. Dylan.
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oK,
UST TRIED WITH A STIMULUS SPAN OF 3.5 TO 4 MEG.
Oops cap lock, anyway.
The smith chart curve starts at the far right, short? or open? UG memory again,,,
anyway the curve starts at the far right, but only curves down to say the 4 to 5 o clock position it doesn't get to the bottom of the display.
so Now what?
Joe WB9SBD / W9ET
toggle quoted message
Show quoted text
On 2/20/2022 12:20 PM, W0LEV wrote: It's best to measure the capacitor at the frequency of interest, especially
as that frequency increases. For a "sticker value", use a low frequency -
1 MHz or less. As the frequency increases, parasitic inductance becomes
more and more evident which cancels some of the effective capacitance.
Dave - W?LEV
On Sun, Feb 20, 2022 at 2:52 PM Joe WB9SBD<nss@...> wrote:
What is a typical stimulus range for measuring a Cap?
If it makes any difference it is a 500pf cap, and is used between 3.5
and 4 Mhz.
Should I set the stimulus rage for those values?
And the measurement should be taken when the smith chart tracer thing is
right at the bottom like 6 O'clock position correct?
Joe WB9SBD / W9ET
|
Re: Proper way to measure length of _Window_Line_?
On 2/20/22 10:20 AM, Roger Need via groups.io wrote: On Sun, Feb 20, 2022 at 07:01 AM, Jim Lux wrote:
- Or, you can mathematically transform measurements made assuming 50
ohms into measurements using some other impedance. The NanoVNA won't do
this, but other software can.
Jim - DiSlord has added the capability to change the system impedance for measurements in his recent firmware. It is under the Display menu..
Roger Then hook that twinlead up directly and go for it. That's pretty cool. I thought I had some 300 ohm twinlead in the garage, and I was going to do some tests with transformer and not, etc.? But I didn't, so it will have to wait for the next trip the to store.
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You're not the only one. Oh wait, what were we talking about?
Max
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On Sunday, February 20, 2022, 01:13:22 PM CST, Joe WB9SBD <nss@...> wrote:
I am sorry that I asked that question again.
I'm Old, The Brain is failing.
I am lucky when i go to the basement to get a tool, to be able to remember what tool I went down there to get.
Sorry,
Joe WB9SBD / W9ET
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I am sorry that I asked that question again.
I'm Old, The Brain is failing.
I am lucky when i go to the basement to get a tool, to be able to remember what tool I went down there to get.
Sorry,
Joe WB9SBD / W9ET
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On Sun, Feb 20, 2022 at 06:52 AM, Joe WB9SBD wrote:
What is a typical stimulus range for measuring a Cap?
If it makes any difference it is a 500pf cap, and is used between 3.5
and 4 Mhz.
Here is a previous post where I show how to measure a 365 pF cap in this frequency range.... /g/nanovna-users/message/25725This post was a response to this post >> /g/nanovna-users/topic/87236912#25714Roger
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On Sun, Feb 20, 2022 at 07:55 AM, Larry Rothman wrote: The version 2 and newer Nanovnas use a binary command structure. I do not
think there is a document for them yet so you will have to go through the
open-source firmware to see those.?
Larry - The SAA2 binary protocol is described in this document.... Roger
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ARY SANTOS
Gary W9TD
Dex W4DEX
Jim Allyn - N7JA
Francesco
Roger Need