When I built my 486DX2 in 92, with huge help, my guru said to get 5x7 spiral-bound recipe card set to act as notes that he'd mention, as we go. It worked great!
I had the reference, and writing things down, acted like the only cheat sheet I ever made. Completed, I didn't need it. Writing it down after mentally condensing it forged the memory. Never repeated that, sadly, as it created my best grade ever.
New blood sees things with an unjaundiced eye. Making your own note-set, helps. It's a lil laborious, but almost a one-off.
BillSF9c
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Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Dave,
Slight gaffe on my part... the 100dBuVemf is to calibrate the 60dB over 9 S meter full scale on all Kenwood Transceivers..
The dBuVemf is the kirchoff voltage source for sig generators with 50 ohm output impedances connected to a 50ohm load. It's a painful unit to deal on all but the professional sig generators, ie snapshot of my E4438C Amplitude setting screen..
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Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Just lurking here, but does anyone actually look at an S meter while operating? Just kind of wondering. I'll admit I mostly do contests, so I'm way too busy to worry about the actual S meter reading. I would like it if they removed the S meter and put the front panel real estate to better use. Just me I guess. I used to work for HP/Agilent Microwave, and in that case we worried about 0.01dB in measurements. But on HF if someone actually asks how loud they are I just kinda take a WAG at it. If you are louder than the noise I can hear you, so no problem. I guess we all have our different interests! Oh and yes, I do own a Nano-VNA. Real early one, works great for antenna projects and filters. I did have three HP VNAs before our big fire here, but they went up in smoke with everything else. But the Nano is way easier to move around. Plenty good enough for HF stuff. Ken K6MR ________________________________ From: [email protected] < [email protected]> on behalf of Max via groups.io <kg4pid@...> Sent: Wednesday, February 9, 2022 6:05 PM To: [email protected] < [email protected]> Subject: Re: [nanovna-users] Using NanoVNA to measure receive antenna port impedance #measurement I believe it. My very old (now) Icom 2100 single band VHF radio is even worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase in power from the other end! Just asking, is it really that hard to measure signal strength with even the least bit of accuracy in a radio? Or it they just didn't try? Max KG4PID On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <davearea51a@...> wrote: Input regarding Kenwood S-Meters. I have and have rigorously measured the S-Meter input power vs. S-meter indication. It's off the wall for that radio, if there were a wall!! At some points below S-9, as little as 1 dBm difference produces an additional S-Unit increase/decrease. S-9 is no where near -73 dBm. However, above S-9, it's not bad for every 10 dB increase in input power. If it's not a modern SDR, the S-Meter doesn't mean squat - even the Collins S-Line!!!!!! With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm system. 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV. To be rigorous, the given value of 100 eBuV is incorrect to be rigorous. What's more, what does Kenwood mean by "dBuVEMF"??? What the dickens does the added "EMF" refer to???? Dave - W?LEV On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Yea I kept looking at the data sheet thinking, those dimensions can't be right! As much as wanted to order some to protect my equipment, I quickly realized that it would take a pick-n-place machine to mount those tiny parts in most cases. That tiny part is only .62 mm long or?0.02440945 in inches. Four of them will fit between the pins of the older chips!?
My hat is off to anyone that can do it manually. Don't sneeze or you WILL loose that part!
Max KG4PID
toggle quoted message
Show quoted text
On Wednesday, February 9, 2022, 04:26:40 PM CST, DOUGLAS WYMAN via groups.io <dkwyman@...> wrote: As a reality check for those whose soldering skills might not have kept up to this task (mine for example): The Infineon two terminal part is about the size of Thomas Jefferson¡¯s eyeball on a 2020 nickel. On Feb 4, 2022, at 9:59 AM, N2MS <mstangelo@...> wrote:
I checked this Infineon diode on Mouser and it shows "Not recommended for new design:
<>
Has anyone used this Bourns part:
<>
It has low capacitance the the 0603 size with solderable ends may be easier to solder to the connector.
Mike N2MS
On 02/04/2022 8:38 AM Reinier Gerritsen <r.gerritsen@...> wrote:
Solved this problem a few years ago. I protected my nanovna V2.2 with a
TVS diode: ESD101B102ELE6327XTMA1, a 5.5V TVS bi-directional diode from
Infineon, 0.1 pF capacitance.
Soldered directly at the input on the pcb. I did not see any difference
in return loss matching. You could introduce a series capacitor to
prevent DC connection related failures. I think (not for sure) that the
TX port does not have one, but the RX port does.
Had to replaced the input switches in 3 different nanovnaV2.2? units
failing in a timespan a few days. All units back to life now.
Reinier
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
I believe it. My very old (now) Icom 2100 single band VHF radio is even worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase in power from the other end! Just asking, is it really that hard to measure signal strength with even the least bit of accuracy in a radio? Or it they just didn't try?
Max KG4PID
toggle quoted message
Show quoted text
On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <davearea51a@...> wrote: Input regarding Kenwood S-Meters.? I have and have rigorously measured the S-Meter input power vs. S-meter indication.? It's off the wall for that radio, if there were a wall!!? At some points below S-9, as little as 1 dBm difference produces an additional S-Unit increase/decrease.? S-9 is no where near -73 dBm.? However, above S-9, it's not bad for every 10 dB increase in input power.? If it's not a modern SDR, the S-Meter doesn't mean squat - even the Collins S-Line!!!!!! With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm system.? 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV.? To be rigorous, the given value of 100 eBuV is incorrect to be rigorous.? What's more, what does Kenwood mean by "dBuVEMF"???? What the dickens does the added "EMF" refer to???? Dave - W?LEV On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker.? This equates to -1dBm.? As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily.? Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Input regarding Kenwood S-Meters. I have and have rigorously measured the
S-Meter input power vs. S-meter indication. It's off the wall for that
radio, if there were a wall!! At some points below S-9, as little as 1 dBm
difference produces an additional S-Unit increase/decrease. S-9 is no
where near -73 dBm. However, above S-9, it's not bad for every 10 dB
increase in input power. If it's not a modern SDR, the S-Meter doesn't
mean squat - even the Collins S-Line!!!!!!
With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm
system. 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV. To be
rigorous, the given value of 100 eBuV is incorrect to be rigorous. What's
more, what does Kenwood mean by "dBuVEMF"??? What the dickens does the
added "EMF" refer to????
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
As a reality check for those whose soldering skills might not have kept up to this task (mine for example):
The Infineon two terminal part is about the size of Thomas Jefferson¡¯s eyeball on a 2020 nickel.
toggle quoted message
Show quoted text
On Feb 4, 2022, at 9:59 AM, N2MS <mstangelo@...> wrote:
I checked this Infineon diode on Mouser and it shows "Not recommended for new design:
<>
Has anyone used this Bourns part:
<>
It has low capacitance the the 0603 size with solderable ends may be easier to solder to the connector.
Mike N2MS
On 02/04/2022 8:38 AM Reinier Gerritsen <r.gerritsen@...> wrote:
Solved this problem a few years ago. I protected my nanovna V2.2 with a
TVS diode: ESD101B102ELE6327XTMA1, a 5.5V TVS bi-directional diode from
Infineon, 0.1 pF capacitance.
Soldered directly at the input on the pcb. I did not see any difference
in return loss matching. You could introduce a series capacitor to
prevent DC connection related failures. I think (not for sure) that the
TX port does not have one, but the RX port does.
Had to replaced the input switches in 3 different nanovnaV2.2 units
failing in a timespan a few days. All units back to life now.
Reinier
|
Re: Proper way to measure cable length
OK guys, here's a quick shot I found on the web. don't remember where but hopefully it'll answer your questions.
Mike C.
toggle quoted message
Show quoted text
On 2/7/2022 1:10 PM, Joe wrote: For an example, it is extremely helpful when troubleshooting a transmission line fault. I have an Anritsu Sitemaster that I use to do DTF (Distance to Fault) tests. I can locate a problem, usually within a few feet, and save lots of time taking things apart that are not the problem.
I sometimes test a spool of hardline that we suspect has been shipped improperly on it's side and dropped. This can cause the cable to deform and cause an impedance bump in the line. It's hard for a supplier to deny that the cable is bad when it's still on the spool and never unreeled.
Joe
On 2/7/2022 12:45 PM, Toad Laurence via groups.io wrote:
Dear all,
Could someone answer this:-
???????? Why is there this obsession to electrically measure the physical length of an arbitrary length of coax?
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The wiki page Home
has been updated
by Larry Rothman <nlroth@...>.
Reason: Added Menu Structure Map links
Compare Revisions
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Re: Ver 1.1.01 Menu structure Map
Yep. Printed out a menu map and embellished it with some handwritten notes. For just about every device I have, I also create a "Notes" document, where I add things I find/figure out along the way, like the many things I learn in these and other forums. I do that for each significant piece of radio and lab equipment, my automobiles, etc...
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Re: Wikipedia erases nanovna
I am with Dragan - I found an article that lacked a complete history and what was there was incorrect. I tried to get it corrected and expanded, but I guess the original author had more clout so all my enhancements were rejected.
I worked on a military system in the late 1960s which is and has always been incorrectly described on WikiPedia and I have stopped trying to rectify the fiction.
Bob R - N7WY
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Re: Proper way to measure cable length
Asuming you can physically measure the length of the cable or you can cut a smaller length of the cable. This is my way to find the velocity factor using Dislords fw:
Measure the length of the cable. Connect the cable to CH0 (other end open or closed), and use Messue Cable. Now observe the reported cable length. I the reported length is not the same as the measured physical length then change the velocity factor until it is. The ¡±needed" velocity factor to get the same length is the vf of the cable.
73/SM6AYM
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Show quoted text
8 feb. 2022 kl. 15:10 skrev William Smith <w_smith@...>:
Well, yes, but the OP didn¡¯t specify exactly what he wanted to do, so we¡¯re left guessing. Does he want to measure the physical length of a cable that¡¯s already installed, so he can order a replacement? Does he want to know how much is left on a partial spool? Does he want to make phasing lines? How accurate does he want to be? Various people are answering all the above questions and more, but we don¡¯t know, for instance, if he can cut a few feet off and measure the known length. [And as a consequence, most of the answers will be wrong, because they are answering the wrong question, but we don¡¯t know what the right question is.]
That said, there¡¯s a lot of knowledge in the answers that _have_ been given, so the entire discussion is worthwhile, and very educational.
73, Willie N1JBJ
On Feb 8, 2022, at 5:16 AM, Arie Kleingeld PA3A <pa3a@...> wrote:
Measuring the cable length comes down to measuring the Velocity Factor (VF) first.
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Ver 1.1.01 Menu structure Map
I bought a NanoVNA H-4 and found it good (for my own use).
I drew the MENUmap soft.ver. 1.1.01, when the right kind was not found on the Internet (at least for now).
The MAP can be found in the Photos folder.
73 de Markku oh2blv/oh2oa
|
Sorry about my late entry.. just joined. The ripples on the original 70cm VSWR image are the sort of thing regularly seen in microwave waveguide return loss measurements. These RL/VSWR ripples indicate an impedance mismatch or bump which (as suggested) a TDR can find. The other really interesting behavior which we used in the waveguide world, was the 'frequency difference' of one cycle of that sinusoidal pattern.. in your case I counted 3.5 cycles over the (453.9-436.5Mhz interval), giving 4.971Mhz per cycle (a 60.3m wavelength). With a half wavelength of 30.2m, that would be the free space distance to the mismatch bump point.. However, in coax with say a 0.66 VF (like LMR400), the real distance would be about 19.9m.. which I'd have it a guess is about the length of your coax..
If possible, try and substitute a different length coax, and repeat the measurement.. Just an idea...
David Burger
Chartered PE, Sydney.
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Re: Using NanoVNA to measure receive antenna port impedance
#measurement
During Kenwood transceiver bench alignments, they specify 100dBuVEMF as the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a contest with multi-transmitters, we saw around 3Volts of RF at one receiver (tuned to a different band of course), and it survived quite happily. Best I can make out, the NanoVNA only outputs like -10dBm.. ??
|
Re: Wikipedia erases nanovna
If Wikipedia does not want the NanoVNA entry, please consider using the IEEE sponsored www.ethw.org history wiki. It's the perfect repository for articles, photos, sound and vision..
Being an IEEE Member gains you automatic access, (non-members can request access thru the web master in Piscataway), and naturally, no advertising, promotions, games. It's a great resource I facilitated back in 2014.. It's intended as a history wiki, and contains a lot of ham content... and of course, if its more than a day old - it's history ! Please consider.
David Burger
IEEE History Committee, Past Chair.
|
Early on firmware developers made "Menu Structure Maps" available. Is this,
what is now missing with all the latest firmware?
Is this what Chris is looking for?
Richard K8CYK
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Show quoted text
On Tue, Feb 8, 2022, 3:44 PM Eric KD7CAO <kd7cao@...> wrote: Perhaps the team over at Nifty-Guides could create one. They do a ton of
ham radios and other products.
Eric Gildersleeve
On Tue, Feb 8, 2022, 15:01 Larry Rothman <nlroth@...> wrote:
Chris,
As simple as the NanoVNA looks, there is really no quick reference on how
to use it - it is a full VNA in the real sense.
That is like asking for a QR card for an HP or Anritsu VNA.
However, with that said, there are a few menu structure maps available
either in the Wiki, files section or in various forum messages.
The menu maps are dependent on the version of firmware you have
Of course, since all of the available docs have been written by the
NanoVNA users and submitted to the user group - feel free to distill a QR
card for everyone, by going through the various user guides and messages.
This is not a dig - others before you as well as myself, have done that to
create the current docs you can grab on the user group.
...Larry
On Tuesday, February 8, 2022, 03:27:49 p.m. EST, Chris Edwards via
groups.io <chris_b_edwards@...> wrote:
A ¡°Quick Reference Card¡± that I could print and learn with like in the
field or bench. No app or PC. The Wiki How to (at the end), YouTube,
tells you how but not a ¡°Quick Reference Card¡±.
|
Perhaps the team over at Nifty-Guides could create one. They do a ton of
ham radios and other products.
Eric Gildersleeve
toggle quoted message
Show quoted text
On Tue, Feb 8, 2022, 15:01 Larry Rothman <nlroth@...> wrote: Chris,
As simple as the NanoVNA looks, there is really no quick reference on how
to use it - it is a full VNA in the real sense.
That is like asking for a QR card for an HP or Anritsu VNA.
However, with that said, there are a few menu structure maps available
either in the Wiki, files section or in various forum messages.
The menu maps are dependent on the version of firmware you have
Of course, since all of the available docs have been written by the
NanoVNA users and submitted to the user group - feel free to distill a QR
card for everyone, by going through the various user guides and messages.
This is not a dig - others before you as well as myself, have done that to
create the current docs you can grab on the user group.
...Larry
On Tuesday, February 8, 2022, 03:27:49 p.m. EST, Chris Edwards via
groups.io <chris_b_edwards@...> wrote:
A ¡°Quick Reference Card¡± that I could print and learn with like in the
field or bench. No app or PC. The Wiki How to (at the end), YouTube,
tells you how but not a ¡°Quick Reference Card¡±.
|
Chris,
As simple as the NanoVNA looks, there is really no quick reference on how to use it - it is a full VNA in the real sense.
That is like asking for a QR card for an HP or Anritsu VNA.
However, with that said, there are a few menu structure maps available either in the Wiki, files section or in various forum messages.
The menu maps are dependent on the version of firmware you have
Of course, since all of the available docs have been written by the NanoVNA users and submitted to the user group - feel free to distill a QR card for everyone, by going through the various user guides and messages. This is not a dig - others before you as well as myself, have done that to create the current docs you can grab on the user group.
...Larry
toggle quoted message
Show quoted text
On Tuesday, February 8, 2022, 03:27:49 p.m. EST, Chris Edwards via groups.io <chris_b_edwards@...> wrote:
A ¡°Quick Reference Card¡± that I could print and learn with like in the field or bench.? No app or PC.? The Wiki How to (at the end), YouTube, tells you how but not a ¡°Quick Reference Card¡±.
|
A ¡°Quick Reference Card¡± that I could print and learn with like in the field or bench. No app or PC. The Wiki How to (at the end), YouTube, tells you how but not a ¡°Quick Reference Card¡±.
|
DOUGLAS WYMAN
Mike C.
Lou W7HV
n7wy
Eric KD7CAO