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I have the circuit below, I built to remove Common mode signal from a 225ft CAT6 Feed LINE.
It works extremely well. So now I want to know what loss I have put just before my radio.
(The 225ft feed line is connected to a Beverage on the ground.) Feel free to ignore the antenna.
Per the drawing, CH0 is feeding the 100 ohm input thru a short piece of CAT6 (1ft).
CH1 is connected to the 50 ohm output through a BNC connector with a short piece of coax (1ft).
I ran a scan 550 to 4MHz, I only care about the broadcast band, but it still looks good at 4MHz. (I think)
The display reads,
CH0 10db/ -8.63
CH0 1.0FS 105 ohms 4.07uh This is at 1MHz.
The ohms are pretty flat, the Reactance goes capacitive at 4.2MHz.

CH1 Logmag 10db/ -0.99db
CH1 Phase 90*/ -0.637

What line above is the pass through loss?
How do I account for the 100ohm in to 50ohm out? Or how do I back that out of the numbers.
The only line I understand is "CH0 1.0FS 105 ohms 4.07uh" If it was perfect it would say
"CH0 1.0FS 100 ohms 0.00uh"
Can you describe what the other lines mean?
Thank you Mikek

Great, tnx for the lead. With the saver sw working fine, I should be good to go, makes sense
rich

On Fri, Jun 5, 2020 at 01:53 PM, David Eckhardt wrote:

No, it isn't "you just gotta know". Those of us who actually spend the
time and make the effort to find an engineering sound reference online
which everyone can access to answer the question(s), simply mean to help
and give you a sound answer without your invoking any number of search
engines and avoiding snake oil so prevalent on the www. Chances are we've
"been there, done that" in our training/careers. There are sources online
that put things much clearer and more succinctly than our own wording.
Chances are, we know where to look for clear and concise and engineering
sound answers which all can access and learn if they choose to pursue the
URL's.

I agree with much of what you have said. In the days before the Internet it was a real struggle to find a textbook or magazine article which covered a subject of interest. Nowadays there is a plethora of material available including videos and online courses which can answer most questions with a little effort.

As a bench engineer and electronics/computer science teacher I found that one can only acquire and retain a solid technical understanding by hands-on experimentation, personal study and investigation. Just receiving the answers to a question does not result in good retention of technical material. As they say "no gain without a little pain".

This does not mean that folks like me and other knowledgeable members of this group do not want to help. On the contrary most of us here to share and learn from each other. But I hope that most with a question will at least Google a bit and try and read some of the excellent material available on the Internet before asking basic questions.

Roger Need

Thanks...

No, it isn't "you just gotta know". Those of us who actually spend the
time and make the effort to find an engineering sound reference online
which everyone can access to answer the question(s), simply mean to help
and give you a sound answer without your invoking any number of search
engines and avoiding snake oil so prevalent on the www. Chances are we've
"been there, done that" in our training/careers. There are sources online
that put things much clearer and more succinctly than our own wording.
Chances are, we know where to look for clear and concise and engineering
sound answers which all can access and learn if they choose to pursue the
URL's.

I take the effort of helping others by emailing out sound, correct, no
snake oil references to properly answer question(s) very seriously. If you
don't want to pursue those links, I can't help you. Please don't put them
in the "you just gotta know' category.....please.....

Yes, I'm just a bit offended.

*Example:* Just this week I had to put out yet another "take" on the 101
points allocated to any set frequency span. I just hope others read it and
internalized it and are willing to pass it on to other newbies of the
NANOVNA community. Nothing but VERY SIMPLE algebra, no "higher" math!!!

Distance between points for a given frequency range = (Frequency
Range) / 101.

Of course, if you use SAVER, you can set any number of bins to
greatlyincrease this frequency resolution.

EXAMPLE: Frequency Range defined as 1 through 30 MHz.

Point spacing (resolution: = (30 MHz - 1
MHz) / 101 = 29 MHz / 101 = 0.29 MHz

If I then look specifically at 75/80
meters which spans 3.5 to 4.0 MHz, a total span of 0.5 MHz, I will have
1.74 (at best, 2) points in the whole
band. This is not too terribly useful for looking at tuning a multiband
antenna.

EVERYONE: PLEASE,......P L E A S E,.............., take the above and
pass the 101 point "gotcha" on to other new members of the NANOVNA
community. PLEASE??

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Yes, I think I'll order from Mouser, Newark or Digikey - they have them for around $10ea (I tried to save $$ but....)

The traces on the LCD flex circuit can crack if the flex is bent at a right angle.
Also, a few other forum members have seen this issue - they carefully removed the LCD (just release it from the metal frame around the edges) tilted it up and re-touched the soldering. Then, snap the LCD back into the frame.

Good luck!

Its the activity LED that's flashing, always.
Just tried the usb path and yes that's ok, so a display issue does appear to be the issue, just ran a few sweeps and ok except for screen still white. Will check that, tnx Larry

On Fri, Jun 5, 2020 at 07:26 PM, Larry Rothman wrote:

STM32F303

I’m just asking in parentheses why don’t you buy from a reputable seller? With us, farnell is a good name.

--
*** If you are not part of the solution, then you are the problem. ( ) ***

I guess I am just the opposite. I'm a smart guy and good at figuring things out. I will spend literally hours searching high and low for information before I break down and ask someone. I almost consider it a personal failing if I can't figure it out myself (with the help of those things called "search engines"). Maybe it's partly because I cut my teeth on dialup BBSes run by university professors and students back in the 80s. If you didn't come prepared and not having done your "homework" they would eat you alive.

Keep up the good work guys!

73

-Jim
NU0C

On Fri, 5 Jun 2020 18:07:38 +0000 (UTC)
"Larry Rothman" <nlroth@...> wrote:

Hi Bruce,
This forum is run by Amateurs for Amateurs and the Wiki and Files sections have been put together over time (the forum is 1 year old now!) from questions that were asked and answers that were offered - by forum members.
When one joins this forum, there is a big red arrow on the homepage that says - Look in the WIKI and FILES sections - lots of info there! ...And don't forget the links at the bottom of EVERY emailed post.

And there IS lots of info there - and it is the fact that many of the original members keep seeing the SAME QUESTIONS over and over again that we've just taken to say: Look in the Wiki.
I don't know how much more we could hit these people over the head with the information - but they would rather ask first and look later.
Sorry if that gets your shorts in a knot.

If someone says - "Hey, I looked in the Wiki and didn't find the info, can someone help?" a pile of members will chime in to help.

Please remember - anyone can add/edit Wiki info. If you have what you believe is relevant information for forum members, feel free to add an entry yourself - just keep it to the point and use any web links as needed.
Cheers,
Larry

On Friday, June 5, 2020, 1:52:15 p.m. EDT, BruceN <k4tql@...> wrote:

Gary,

This is something that I have issues with, too.? It reminds me of the day, way back in the day, when I asked someone where I could find documentation regarding the Unix operating system.? This was before the Internet (over 50 years ago).? The answer was "you just gotta know".

When the answers to your questions are "read this wiki" or "read that wiki", the answer is just the same as: "you just gotta know where to look".? It would be just as easy for a response to be furnishing a link to "where" to look.? And, as in your case, maybe you looked there and missed it.? Happens to me all the time.? And maybe there is a better place to look as one responder provided.

I've run into many instance of this smug attitude of "I know and you don't.? Go find it yourself".? I'll bet a lot of them wouldn't know how to solder two wires together without burning themselves for all their "knowledge".? I knew professors of electrical engineering in college who couldn't change their car battery.? That wasn't an electrical task, it was a mechanical task.

And, no I can't answer your questions either.? If you find a good place to find them, let me know.? I need the answers, too.? You might also point out where you have looked unsuccessfully.

BruceN / K4TQL

Which LED is flashing - the charge or the other activity LED?

The activity LED flashes as a sweep is occurring. If you're only getting a white screen, check that a solder connection under the LCD has not cracked.

Can you still access the device via the console over a USB connection? If YES, then it sounds like an LCD issue.

Good luck

Hi Bruce,
This forum is run by Amateurs for Amateurs and the Wiki and Files sections have been put together over time (the forum is 1 year old now!) from questions that were asked and answers that were offered - by forum members.
When one joins this forum, there is a big red arrow on the homepage that says - Look in the WIKI and FILES sections - lots of info there! ...And don't forget the links at the bottom of EVERY emailed post.

And there IS lots of info there - and it is the fact that many of the original members keep seeing the SAME QUESTIONS over and over again that we've just taken to say: Look in the Wiki.
I don't know how much more we could hit these people over the head with the information - but they would rather ask first and look later.
Sorry if that gets your shorts in a knot.

If someone says - "Hey, I looked in the Wiki and didn't find the info, can someone help?" a pile of members will chime in to help.

Please remember - anyone can add/edit Wiki info. If you have what you believe is relevant information for forum members, feel free to add an entry yourself - just keep it to the point and use any web links as needed.
Cheers,
Larry

hi Gyula,
tnx for the info on your site on different models. Was there something there related to the problem I posted that maybe I missed?

Gary,

This is something that I have issues with, too. It reminds me of the day, way back in the day, when I asked someone where I could find documentation regarding the Unix operating system. This was before the Internet (over 50 years ago). The answer was "you just gotta know".

When the answers to your questions are "read this wiki" or "read that wiki", the answer is just the same as: "you just gotta know where to look". It would be just as easy for a response to be furnishing a link to "where" to look. And, as in your case, maybe you looked there and missed it. Happens to me all the time. And maybe there is a better place to look as one responder provided.

I've run into many instance of this smug attitude of "I know and you don't. Go find it yourself". I'll bet a lot of them wouldn't know how to solder two wires together without burning themselves for all their "knowledge". I knew professors of electrical engineering in college who couldn't change their car battery. That wasn't an electrical task, it was a mechanical task.

And, no I can't answer your questions either. If you find a good place to find them, let me know. I need the answers, too. You might also point out where you have looked unsuccessfully.

BruceN / K4TQL

--
*"To invent, you need a good imagination and a pile of junk"* -- Thomas Alva Edison (1847-1931)

Well, unfortunately it appears I was sent a defective STM32F303.
I removed it and put the original F072 back and my Nano is working again.
I thought I might have a problem when I saw that the seller had wrapped shipping tape around the chip carrier to hold the F303 in place. So much for no antistatic precautions.

I'll have to see if the seller will send me a replacement, wrapped in aluminum foil.

Hello,
What I have not seen up to now is a *permission* problem fix with the access to the USB serial port (nanoVNA).

What to do:
# Add user to group dialout, for USB-Serial access.
$ sudo usermod -a -G dialout <user name>
# Reboot
$ groups
rudi adm dialout cdrom sudo dip plugdev lpadmin lxd sambashare vboxsf
# "dialout" must show up in the list.

73, Rudi DL5FA

Finger mistake
20Log(10)(1/67) = –36dB

Weird! I tried get it working on my Windows PC, and everything seemed to be going fine. However, while using the calibration assistant built-in to NanoVNASaver, I had a similar crash due to pyserial. This was also with Python 3.7 instead of 3.8 that I have on my Linux box. Now I'm starting to suspect the firmware that I flashed last year, ttrftech version 0.5.0-1. Further experimentation needed.

Although I got my NanoVNA back in ?February? I have not taken time to work with it much. I did purchase a bag with ?10? PCB edge mount SMA connectors and after yesterday’s traffic about “NanoVna Test fixture” decided it was time to get some PCB copper clad and a Dremmel and make up my “Fixture In A Hurry”. See attached.

I though what might be fun to test and the transformer I use in a HV power supply came to mind.
It is a CoilCraft part number: FL2015-2LB
I drove the secondary and measure the primary. Both primary and secondary I loaded with 50ohms shunt to ground. (Was the shunt a good idea?)

Turns ratio 1:67 so, if I am operating the calculator correctly this should be 10Log(10)(1/67) = –36dB




I measured S11 and S21 with NanoVNA Saver.


The S21 measurement way down at 50KHz. is about the –36 predicted.
Note the S21 measurement gets the saw tooths (sawteeth?) soon after 50KHz.

+++++++++++++++
Lee Erickson
Spectrum Techniques LLC.
lee@...

Lee,
When accessing web links, if you find a dead link, go up one level to see if anything has changed.
If you look at
You will see there is a German and English folder.
Have a look in those folders and you will find the updated filename info.
I will update the forum wiki.
Cheers,
Larry