开云体育

When you finally receive your new toy/tool/instrument,? try calibrating it a few times to get the hang of it. When calibrating, don't forget to hit the Reset key on the display before the Calibrate key.
Also, check the version of firmware it came with. You may want?to flash the last version of DiSlord's firmware into your Nanovna. Note that you cannot brick the device, if the flash failed, you just try again.?
Please read the various user guides mentioned in the forum's Wiki and watch some of the YouTube videos. There is a learning curve if you've never used a VNA before.?
Cheers,?
Larry. VE3LRI


On Thu, 3 Dec 2020 at 8:11 PM, Ken Sejkora<kjsejkora@...> wrote: Thanks Larry.? I’ll give it a shot.? I figured it was possible, but haven’t yet received my nanovna to run any experiments.

Thanks again --? Ken


From: Larry Rothman
Sent: Thursday, December 3, 2020 08:09 PM
To: [email protected]
Subject: Re: [nanovna-users] TDR measurements of twisted-pair cable

H

Thanks Larry. I’ll give it a shot. I figured it was possible, but haven’t yet received my nanovna to run any experiments.

Thanks again -- Ken


From: Larry Rothman
Sent: Thursday, December 3, 2020 08:09 PM
To: [email protected]
Subject: Re: [nanovna-users] TDR measurements of twisted-pair cable

H

Hi Ken,
Yes, you can use the Nanovna to do TDR on just about any piece of wire/cable. I used it on a power cord just to see if it worked (yup).
You will have to experiment with the velocity correction factor though using a known length of cable.?
... Larry


On Thu, 3 Dec 2020 at 8:02 PM, Ken Sejkora<kjsejkora@...> wrote: Sorry my earlier question went out attached as a reply to a different discussion thread.? I thought I had started a new thread.

Has anyone in the group used a nanovna to run TDR tests on twisted-pair cables to measure length of cable or distance to a fault? Although not a coaxial cable, most references list a characteristic impedance of about 100 ohms and velocity factor at about 0.65.? Does anyone have tips for using a nanovna calibrated for 50 ohms to measure such twisted pair cable?
Thanks and 73.
Ken, WB?OCV

Sorry my earlier question went out attached as a reply to a different discussion thread. I thought I had started a new thread.

Has anyone in the group used a nanovna to run TDR tests on twisted-pair cables to measure length of cable or distance to a fault? Although not a coaxial cable, most references list a characteristic impedance of about 100 ohms and velocity factor at about 0.65.? Does anyone have tips for using a nanovna calibrated for 50 ohms to measure such twisted pair cable?
Thanks and 73.
Ken, WB?OCV

Has anyone in the group used a nanovna to run TDR tests on twisted-pair cables to measure length of cable or distance to a fault? Although not a coaxial cable, most references list a characteristic impedance of about 100 ohms and velocity factor at about 0.65.? Does anyone have tips for using a nanovna calibrated for 50 ohms to measure such twisted pair cable?
Thanks and 73.
Ken, WB?OCV

It is VERY well done, both from an eye-candy point of view and content. One
does not have to be an RF Engineer to follow it, yet it certainly is better
than most 'beginner's guides'.

Congrats! Very nice job.
73, N0AN
Hasan


On Thu, Dec 3, 2020 at 3:38 PM Jim Brown via groups.io <w5zit=
[email protected]> wrote:

Barry gave his presentation to our club (OroValley ARC) and it was very
well received. I think we had 50 or 60 attendees in our Zoom meeting, so
it was very worthwhile. And Barry had to wait until very late to give the
presentation as we are in Arizona.

Get in touch with him if you have a group large enough to make a
presentation worth his time.

73 - Jim W5ZIT

Barry gave his presentation to our club (OroValley ARC) and it was very well received. I think we had 50 or 60 attendees in our Zoom meeting, so it was very worthwhile. And Barry had to wait until very late to give the presentation as we are in Arizona.

Get in touch with him if you have a group large enough to make a presentation worth his time.

73 - Jim W5ZIT

Oh,.....yes....... The PDP11: a slide rule with a cord!

I forgot about the Sinclair. But, thanks for reminding me of those
days......

Dave - W?LEV

On Thu, Dec 3, 2020 at 6:27 PM Stephen Laurence <Gaslaurence@...>
wrote:

Very interesting.

Although a retired doctor, my main hobby from the age of 10 was radio and
electronics. I had jars of components salvaged from old 1960s televisions,
drawers full of WW2 valves and a small handful of precious germaneum
transistors.

I have actually polished disc heads- I got into vintage computers in the
1970s (long story from university onwards). It was an antique RK05 for a
pdp8. I knew the emergency power fail head retract batteries were bad and I
had just tripped over the mains cable to the cabinet. A loud bang of
shorted mains, then the sound of the drive slowing down, then the screech
as the heads touched the disc surface- there was no way to prevent it. I
was using a 6ft tall rack of pdp8 stuff to act as a serial to parallel
converter, between a Sinclair QL which was sending serial data printing out
my thesis to parallel daisywheel printer !! This was in 1985. I still have
the pdp8 (and some other antique computer stuff).

I saved the heads, but had to scrap the disc platter. I polished them
still attached as I had no means of re-aligning them if I took them off.

As a lesson on esd protection (see other threads), the live mains wire had
contacted the earth in the mains plug. One buffer chip was damaged on the
pdp8 serial interface card from Sinclair QL. The interface card to the
printer and the printer were ok. The rest of the pdp8 apart from the
crashed disc drive head was ok. The Sinclair Ql was trashed (they cost ?400
in 1985) along with the converted portable television I was using as the
monitor.

It delayed the printup of my MD thesis for some time as the main word
processor (QL) was blown.

Steve L

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

Yes, I think it would. I am considering venturing in myself, (repars/mods, rather than construction).

It would make a change from the hot air sometimes emanating from ‘er indoors.

Steve L

Very interesting.

Although a retired doctor, my main hobby from the age of 10 was radio and electronics. I had jars of components salvaged from old 1960s televisions, drawers full of WW2 valves and a small handful of precious germaneum transistors.

I have actually polished disc heads- I got into vintage computers in the 1970s (long story from university onwards). It was an antique RK05 for a pdp8. I knew the emergency power fail head retract batteries were bad and I had just tripped over the mains cable to the cabinet. A loud bang of shorted mains, then the sound of the drive slowing down, then the screech as the heads touched the disc surface- there was no way to prevent it. I was using a 6ft tall rack of pdp8 stuff to act as a serial to parallel converter, between a Sinclair QL which was sending serial data printing out my thesis to parallel daisywheel printer !! This was in 1985. I still have the pdp8 (and some other antique computer stuff).

I saved the heads, but had to scrap the disc platter. I polished them still attached as I had no means of re-aligning them if I took them off.

As a lesson on esd protection (see other threads), the live mains wire had contacted the earth in the mains plug. One buffer chip was damaged on the pdp8 serial interface card from Sinclair QL. The interface card to the printer and the printer were ok. The rest of the pdp8 apart from the crashed disc drive head was ok. The Sinclair Ql was trashed (they cost ?400 in 1985) along with the converted portable television I was using as the monitor.

It delayed the printup of my MD thesis for some time as the main word processor (QL) was blown.

Steve L

I was once on a project and the local shop sent me a tech to help me out. I
had to replace some resistors on a board. Unsolder the old and then insert
and solder the new. The tech did not have any idea how to solder or even
how to use a soldering iorn.

On Thu, Dec 3, 2020, 11:57 AM Larry Macionski via groups.io <am_fm_radio=
[email protected]> wrote:

Hate to say it guys-
Our generation really rocked in the Electronics department. Ken Burns
where are you??? (Ken is the mastery behind the PBS series, "Empire of the
Air", "Baseball" and "The Civil war")

Remember the days of getting on a plane with a Tektronics 465 scope - you
did not leave it for baggage to handle, as God forbid you land and the
scope is on a trip to the Bahamas.. We did component level repair.. Even on
disk drives. Someone mentioned the CDC drives with "Cake-Box" removable
platters. I had a head alignment pack and the $3,000 repair simulator, you
could completely service that 80 or 300Mb disk drive. with The repair
simulator and it was as big as your Tektronics 465 scope. Then you had
17-18 heads to align. You tightened them down with a inch-ounce torque
wrench. I had one site with about 25 of those CDC 300Mb drives.. The
operator loaded a platter, it didn't work, so he went down the line loading
that bad platter in perfectly good disk drives faulting At least 5-8 before
calling the boss, as it was a Saturday; he was alone. The boss,
immediately stopped him from loading it in yet another disk drive, They
called me in, I grabbed everything I had.. But I never had a complete set
of heads.. There was an upper, a lower and a servo.. I had about 10-12. I
spent 20-30 hours on site.. Removing heads, polishing them on IBM punch
cards with toluene, to remove the iron oxide, then inspecting them as the
heads flew only microns above the platters. Re installing them, changing
absolute filters and I think I got better than 1/2 of the damaged drives
back up, that weekend. Then ordering parts... Kids today have no idea,
about how a disk drive works. What a low level format is, or bad block
lists are. They replace sub assemblies. Do they even carry a soldering
iron, or even a wire wrap tool?. They don' t carry scopes.

So here's to us old farts.. the guys that knew if a 200 ohm resistor was
bad and you didn;t have one in your resistor box, what resistors you could
connect together to replace that 200 ohm resistor...

I once flew into Syracuse NY, and rented a car -off to the hospital in Old
Forge, NY. hours away.. I was working on a Gamma Camera.. Found a shorted
0.01uf It was taking down a power supply. Who has a 0.01uf cap go bad?
Well, I Found that a ham worked at the hospital and we went with him to his
hamshack and he had a baby food jar full of disk ceramics. We fixed the
gamma camera. Had I had to go back to Syracuse to find an electronic parts
store, It would of downed the equipment for another day plus doubled or
tripled the bill..

Kids today do not have the where with all to be able to provide the
customer satisfaction we did on a daily basis. Today's throw away society.

So I raise my beer to those who worked past midnight, and were back at
other calls by 8am the next morning. And fixed things, didn't replace them.

PS: I also remember those huge magnetic disks and the machines in which
they operated. About half the size of today's refrigerator/freezers which
stood about waist high. Heaven forbid, should anyone jar the floor on
which they stood resulting in a crashed head. The bearings were air, yes,
microns above the valued disk. How about the HP-9845 "computers"? Those
were the cat's meow in their day. And I started my career using slide
rules. Oh my,........now I'm going back to the Precambrian era........
And the first use of the PET PC in our design group - we had only one for
12 engineers? It was barely powerful enough to determine if all the piece
parts in a given functional circuit design could fit on the real estate
challenged board. Not even powerful enough for any simple circuit
simulations.........

Again, thank you for taking me back to my "fossil-in-the-making" days ! ! !
! Good memories!!!!! ????

Dave - W?LEV



On Thu, Dec 3, 2020 at 5:46 PM David Eckhardt via groups.io <davearea51a=
[email protected]> wrote:

Larry, you sure bring back memories!!!! While I was on the R&D, design,
and prototype end of things, we went through very similar 'exercises'. And
I venture a theory, time will tell if it hasn't already done so, that we
worked during the best of times in the electronic and technical
industries. Yes, troubleshooting to the part level sure taught us about
everything we needed to know about any circuit in existance or could be
imagined! In home brewing at present, if I don't have the required value
of something, the first thing I consider before hitting the Digikey site is
what do I have that can be seriesed or paralleled to yield the value I
need. Good tools to cultivate! In my experience over the last decade of
working, I found the newbies can't even tackle Ohm's Law, DC, don't even
mention complex sources or loads....... True: the
newbies have no clue, what-so-ever.

Thank you for taking me back to my 'fossil-in-the-making' days. Now
retired at 74 and value everything I learned in the process.

Dave - W?LEV

On Thu, Dec 3, 2020 at 4:57 PM Larry Macionski via groups.io <am_fm_radio=
[email protected]> wrote:

Hate to say it guys-
Our generation really rocked in the Electronics department. Ken Burns
where are you??? (Ken is the mastery behind the PBS series, "Empire of

the

Air", "Baseball" and "The Civil war")

Remember the days of getting on a plane with a Tektronics 465 scope - you
did not leave it for baggage to handle, as God forbid you land and the
scope is on a trip to the Bahamas.. We did component level repair.. Even

on

disk drives. Someone mentioned the CDC drives with "Cake-Box" removable
platters. I had a head alignment pack and the $3,000 repair simulator,

you

could completely service that 80 or 300Mb disk drive. with The repair
simulator and it was as big as your Tektronics 465 scope. Then you had
17-18 heads to align. You tightened them down with a inch-ounce torque
wrench. I had one site with about 25 of those CDC 300Mb drives.. The
operator loaded a platter, it didn't work, so he went down the line

loading

that bad platter in perfectly good disk drives faulting At least 5-8

before

calling the boss, as it was a Saturday; he was alone. The boss,
immediately stopped him from loading it in yet another disk drive, They
called me in, I grabbed everything I had.. But I never had a complete set
of heads.. There was an upper, a lower and a servo.. I had about 10-12. I
spent 20-30 hours on site.. Removing heads, polishing them on IBM punch
cards with toluene, to remove the iron oxide, then inspecting them as the
heads flew only microns above the platters. Re installing them, changing
absolute filters and I think I got better than 1/2 of the damaged drives
back up, that weekend. Then ordering parts... Kids today have no idea,
about how a disk drive works. What a low level format is, or bad block
lists are. They replace sub assemblies. Do they even carry a soldering
iron, or even a wire wrap tool?. They don' t carry scopes.

So here's to us old farts.. the guys that knew if a 200 ohm resistor was
bad and you didn;t have one in your resistor box, what resistors you

could

connect together to replace that 200 ohm resistor...

I once flew into Syracuse NY, and rented a car -off to the hospital in

Old

Forge, NY. hours away.. I was working on a Gamma Camera.. Found a shorted
0.01uf It was taking down a power supply. Who has a 0.01uf cap go bad?
Well, I Found that a ham worked at the hospital and we went with him to

his

hamshack and he had a baby food jar full of disk ceramics. We fixed the
gamma camera. Had I had to go back to Syracuse to find an electronic

parts

store, It would of downed the equipment for another day plus doubled or
tripled the bill..

Kids today do not have the where with all to be able to provide the
customer satisfaction we did on a daily basis. Today's throw away

society.

So I raise my beer to those who worked past midnight, and were back at
other calls by 8am the next morning. And fixed things, didn't replace

them.

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

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

Larry, you sure bring back memories!!!! While I was on the R&D, design,
and prototype end of things, we went through very similar 'exercises'. And
I venture a theory, time will tell if it hasn't already done so, that we
worked during the best of times in the electronic and technical
industries. Yes, troubleshooting to the part level sure taught us about
everything we needed to know about any circuit in existance or could be
imagined! In home brewing at present, if I don't have the required value
of something, the first thing I consider before hitting the Digikey site is
what do I have that can be seriesed or paralleled to yield the value I
need. Good tools to cultivate! In my experience over the last decade of
working, I found the newbies can't even tackle Ohm's Law, DC, don't even
mention complex sources or loads....... True: the
newbies have no clue, what-so-ever.

Thank you for taking me back to my 'fossil-in-the-making' days. Now
retired at 74 and value everything I learned in the process.

Dave - W?LEV

On Thu, Dec 3, 2020 at 4:57 PM Larry Macionski via groups.io <am_fm_radio=
[email protected]> wrote:

Hate to say it guys-
Our generation really rocked in the Electronics department. Ken Burns
where are you??? (Ken is the mastery behind the PBS series, "Empire of the
Air", "Baseball" and "The Civil war")

Remember the days of getting on a plane with a Tektronics 465 scope - you
did not leave it for baggage to handle, as God forbid you land and the
scope is on a trip to the Bahamas.. We did component level repair.. Even on
disk drives. Someone mentioned the CDC drives with "Cake-Box" removable
platters. I had a head alignment pack and the $3,000 repair simulator, you
could completely service that 80 or 300Mb disk drive. with The repair
simulator and it was as big as your Tektronics 465 scope. Then you had
17-18 heads to align. You tightened them down with a inch-ounce torque
wrench. I had one site with about 25 of those CDC 300Mb drives.. The
operator loaded a platter, it didn't work, so he went down the line loading
that bad platter in perfectly good disk drives faulting At least 5-8 before
calling the boss, as it was a Saturday; he was alone. The boss,
immediately stopped him from loading it in yet another disk drive, They
called me in, I grabbed everything I had.. But I never had a complete set
of heads.. There was an upper, a lower and a servo.. I had about 10-12. I
spent 20-30 hours on site.. Removing heads, polishing them on IBM punch
cards with toluene, to remove the iron oxide, then inspecting them as the
heads flew only microns above the platters. Re installing them, changing
absolute filters and I think I got better than 1/2 of the damaged drives
back up, that weekend. Then ordering parts... Kids today have no idea,
about how a disk drive works. What a low level format is, or bad block
lists are. They replace sub assemblies. Do they even carry a soldering
iron, or even a wire wrap tool?. They don' t carry scopes.

So here's to us old farts.. the guys that knew if a 200 ohm resistor was
bad and you didn;t have one in your resistor box, what resistors you could
connect together to replace that 200 ohm resistor...

I once flew into Syracuse NY, and rented a car -off to the hospital in Old
Forge, NY. hours away.. I was working on a Gamma Camera.. Found a shorted
0.01uf It was taking down a power supply. Who has a 0.01uf cap go bad?
Well, I Found that a ham worked at the hospital and we went with him to his
hamshack and he had a baby food jar full of disk ceramics. We fixed the
gamma camera. Had I had to go back to Syracuse to find an electronic parts
store, It would of downed the equipment for another day plus doubled or
tripled the bill..

Kids today do not have the where with all to be able to provide the
customer satisfaction we did on a daily basis. Today's throw away society.

So I raise my beer to those who worked past midnight, and were back at
other calls by 8am the next morning. And fixed things, didn't replace them.

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

Hi Larry,

I agree with you completely. I'm an "old iron" too, and my job is to educate
young students in (power)electronics, digital technology, and something
more. Also I'm a trainer for people, which want to get their HAM-licence.
These people are very interesting in electronics and HAM-stuff.
Not so my students.
I have a lot of electronic and measurement equipment in my shack and I know,
how to handle with it.
Most of the young people have only 4 interests:
1. Is there WiFi available?
2. Is the cellphone battery fully charged?
3. Where is the next party?
4. Are there enough girls to "screw them up".

Working in their job, get a good education for their profession and get the
knowledge to repair things instead of put them in the waste... NOTHING!
Cellphone battery is damaged? Exchange the battery? No, throw it away and
ask granny for a amount of bucks to get a new one.
This is our future?! Awful...
Too much money, to less interestings.

I guess, the chinese citizens will "overun" our economics with high speed in
the next future.

Mr. Spock says: "According to my calculations... you are an idiot". This is
our youth...

So, off-topic mode ends here.

Have a great day


vy 73, DL1UPK

-----Ursprüngliche Nachricht-----
Von: [email protected] [mailto:[email protected]] Im Auftrag von
Larry Macionski via groups.io
Gesendet: Donnerstag, 3. Dezember 2020 17:58
An: [email protected]
Betreff: Re: [nanovna-users] My $165,000 VNA

Hate to say it guys-
Our generation really rocked in the Electronics department. Ken Burns where
are you??? (Ken is the mastery behind the PBS series, "Empire of the Air",
"Baseball" and "The Civil war")

Remember the days of getting on a plane with a Tektronics 465 scope - you
did not leave it for baggage to handle, as God forbid you land and the scope
is on a trip to the Bahamas.. We did component level repair.. Even on disk
drives. Someone mentioned the CDC drives with "Cake-Box" removable platters.
I had a head alignment pack and the $3,000 repair simulator, you could
completely service that 80 or 300Mb disk drive. with The repair simulator
and it was as big as your Tektronics 465 scope. Then you had 17-18 heads to
align. You tightened them down with a inch-ounce torque wrench. I had one
site with about 25 of those CDC 300Mb drives.. The operator loaded a
platter, it didn't work, so he went down the line loading that bad platter
in perfectly good disk drives faulting At least 5-8 before calling the boss,
as it was a Saturday; he was alone. The boss, immediately stopped him from
loading it in yet another disk drive, They called me in, I grabbed
everything I had.. But I never had a complete set of heads.. There was an
upper, a lower and a servo.. I had about 10-12. I spent 20-30 hours on
site.. Removing heads, polishing them on IBM punch cards with toluene, to
remove the iron oxide, then inspecting them as the heads flew only microns
above the platters. Re installing them, changing absolute filters and I
think I got better than 1/2 of the damaged drives back up, that weekend.
Then ordering parts... Kids today have no idea, about how a disk drive
works. What a low level format is, or bad block lists are. They replace sub
assemblies. Do they even carry a soldering iron, or even a wire wrap tool?.
They don' t carry scopes.

So here's to us old farts.. the guys that knew if a 200 ohm resistor was bad
and you didn;t have one in your resistor box, what resistors you could
connect together to replace that 200 ohm resistor...

I once flew into Syracuse NY, and rented a car -off to the hospital in Old
Forge, NY. hours away.. I was working on a Gamma Camera.. Found a shorted
0.01uf It was taking down a power supply. Who has a 0.01uf cap go bad?
Well, I Found that a ham worked at the hospital and we went with him to his
hamshack and he had a baby food jar full of disk ceramics. We fixed the
gamma camera. Had I had to go back to Syracuse to find an electronic parts
store, It would of downed the equipment for another day plus doubled or
tripled the bill..

Kids today do not have the where with all to be able to provide the customer
satisfaction we did on a daily basis. Today's throw away society.

So I raise my beer to those who worked past midnight, and were back at other
calls by 8am the next morning. And fixed things, didn't replace them.

I drink to that and your story hit me perfectly.
I was a MEOREX Telex engineer back in the old days. The story about the computer operator takes one faulty disk-pack (200MB). Mount it on one drive, only for the heads to crash, move the pack to next drive, same thing and again and again, until he reach the end of the disk-sting (8 drives) He then realised there must be something else going on here... Yeah the good-ole 465 and 475. What a universal fault finding tool. I still have one, I bought one at a ham-fest for meagre ?50. I could not resist. Such a good old friend and it serves me great in my ham shack.
Sorry the topic is off nanoVNA but I couldn't resist joining in on stories like this and I'm not going to open up the subject of fault finding down to chip level on Sperry Univac mainframes, series 90 and 1100. GOSH!!! That’s another story, talking about working under pressure when a mainframe went down. Ugh!

And back then if you needed a component it was probably a 30-60 minute trip to the local Radio Shack, even in rural areas.

Hate to say it guys-
Our generation really rocked in the Electronics department. Ken Burns where are you??? (Ken is the mastery behind the PBS series, "Empire of the Air", "Baseball" and "The Civil war")

Remember the days of getting on a plane with a Tektronics 465 scope - you did not leave it for baggage to handle, as God forbid you land and the scope is on a trip to the Bahamas.. We did component level repair.. Even on disk drives. Someone mentioned the CDC drives with "Cake-Box" removable platters. I had a head alignment pack and the $3,000 repair simulator, you could completely service that 80 or 300Mb disk drive. with The repair simulator and it was as big as your Tektronics 465 scope. Then you had 17-18 heads to align. You tightened them down with a inch-ounce torque wrench. I had one site with about 25 of those CDC 300Mb drives.. The operator loaded a platter, it didn't work, so he went down the line loading that bad platter in perfectly good disk drives faulting At least 5-8 before calling the boss, as it was a Saturday; he was alone. The boss, immediately stopped him from loading it in yet another disk drive, They called me in, I grabbed everything I had.. But I never had a complete set of heads.. There was an upper, a lower and a servo.. I had about 10-12. I spent 20-30 hours on site.. Removing heads, polishing them on IBM punch cards with toluene, to remove the iron oxide, then inspecting them as the heads flew only microns above the platters. Re installing them, changing absolute filters and I think I got better than 1/2 of the damaged drives back up, that weekend. Then ordering parts... Kids today have no idea, about how a disk drive works. What a low level format is, or bad block lists are. They replace sub assemblies. Do they even carry a soldering iron, or even a wire wrap tool?. They don' t carry scopes.

So here's to us old farts.. the guys that knew if a 200 ohm resistor was bad and you didn;t have one in your resistor box, what resistors you could connect together to replace that 200 ohm resistor...

I once flew into Syracuse NY, and rented a car -off to the hospital in Old Forge, NY. hours away.. I was working on a Gamma Camera.. Found a shorted 0.01uf It was taking down a power supply. Who has a 0.01uf cap go bad? Well, I Found that a ham worked at the hospital and we went with him to his hamshack and he had a baby food jar full of disk ceramics. We fixed the gamma camera. Had I had to go back to Syracuse to find an electronic parts store, It would of downed the equipment for another day plus doubled or tripled the bill..

Kids today do not have the where with all to be able to provide the customer satisfaction we did on a daily basis. Today's throw away society.

So I raise my beer to those who worked past midnight, and were back at other calls by 8am the next morning. And fixed things, didn't replace them.

Bob
Great suggestion ... will change.
As a physics teacher, I know electrons themselves do not move very far.

I liked the mechanical analogy of "grampy pushing grandchild on a swing"
It works best if Grampy pushes at JUST the right time - PHASE is the key.
Think of grandchild on swing as the RF signal traveling back/forth along the dipole.
Think of grampy as the "push" from the feed line.
I guess this is more like an "END-FED half-wave dipole" isn't it.
So much for analogies.

Agn, TU
Barry k3eui

Ross
What are "presentation notes"?
I put these slides together over a period of about a month.
I think there are something like 12 versions or drafts now.

There are no "notes".... or the notes are all in my head, not on paper.
Maybe that's just the way I think.

In a "live" Zoom however, I would comment on each of these slides and not just read them.
My background is teaching high school physics for four decades.

De k3eui Barry

Barry - I like the presentation very much!
One small suggestion: on slide 45 it says "electrons must travel the length of twice the dipole length in one RF cycle". Instead of "electrons" it should probably say "electromagnetic wave". Electrons can't travel at the speed of light, and mostly they don't really travel anywhere - just jiggle around near their initial location. The EM field surrounding the conductor is what carries the RF energy, and it does travel at speed of light.
(similar suggestions for slide 46, e.g., "current speed" should be electromagnetic wave speed)
regards
Bob n7cii