powering an SWR meter from transceiver output
Hello.
I am working on an ATtiny power / SWR meter, basically a smarter
replacement of the famous Tayloe SWR bridge. It will be a 1W to 5W (maybe a
bit higher, up to 10W) QRP resistive bridge with 6 LEDs analog-like
baragraph, with the intensity being interpolated between two successive
LEDs enhancing the baragraph resolution to at least 4x6 levels (I can
easily recognize 1 LED illuminated from 2 LEDs equally illuminated and 1
LED illuminated significantly stronger than the other). I have the
baragraph electronics and code prototyped, it works quite nicely.
The electronics (ATtiny13A driving the 6 LEDs) will be powered from a 3V
low drop low low quiescent current 16V max input linear regulator, and the
linear regulator will be powered with a 1:2 or 1:3 transformer from the
radio RF power, rectified by a single 1n5711 shottky diode (the diodes will
be used in the bridge anyway, so to reduce the BOM complexity). Look ma, no
batteries.
There will be a larger capacitor at the input side of the regulator, so the
microprocessor will have couple of seconds to perform additional tasks
after key up, that is to show the input power with quite a high accuracy.
So there will be no button: SWR will be shown during key down, and power
will be shown after a second or so after key up.
I feel quite confident with digital design and programming, but I am not
quite sure about the RF
side. Namely, what transformer should I use to feed the linear regulator?
These are my back of the envelope calculations:
On the transceiver output, when loaded with an open resistive bridge (all
three resistors 50 Ohm), the SWR is 2:1 and the voltage at the transceiver
output is 1.3333 * of Vpeak (assuming 50 Ohm output impedance of the
transceiver). Likely the maximum voltage will be lower as the output
impedance of the transceiver PA is not resistive. These are the maxima:
10W -> 42.16V Vpeak at SWR 2:1
7W -> 35.28V Vpeak at SWR 2:1
6W -> 32.65V Vpeak at SWR 2:1
5W -> 29.81V Vpeak at SWR 2:1
The minimum Vpeak at 1W transceiver output with the resistive bridge
shorted (again producing SWR 2:1 at the transceiver) will be minimum 8V
assuming the transceiver PA output is resistive. If not, the output voltage
will be closer to 10V peak.
Now the digital circuit requires a minimum 3.1V at 1.5mA DC before the
linear stabilizer, and the power will be rectified with a single diode, but
the micro will likely work happily down to 2V even if the linear regulator
just passes the voltage unregulated, as the micro may use its internal 1.1V
voltage reference for measurements. Operating the micro unregulated sounds
unusual, but it may be a viable option if tested, especially if the input
voltage will be stable enough due to the large capacitor before the
regulator.
Now my question is:
1) Should I use a 1:2 or 1:3 transformer? Using the 1:2 transformer may
require additional zener diode and likely a resistor before the linear
stabilizer if the input voltage could exceed 16V peak.
2) What will be the tiniest / cheapest ferrite and how many widings will be
optimal? I suppose this decision will be strongly dependent on the bands
supported. My personal goal is a 40m-20m EFHW tuner.
And also:
Will there be an interest for a kit?
Through hole or SMD? It may be a nice "introduction to SMD" kit as the
number of parts will be pretty low.
What bands?
What power range?
Should it contain an EFHW tuner? My personal preference would be a "NJQRP
Rainbow Tuner" like setup covering 40m-20m with a T50-6 transformer, mica
compression capacitor trimmer, jumpers to select the primary winding with
another jumper to add a capacitance for 40m coverage.
Thanks and 73,
Vojtech OK1IAK (former AB2ZA)
|
It is up to US$168 now and includes the Rutledge book with it. Needless to say, the book goes for US$60 or so on Amazon so it's a decent price overall.
--
William, K6WHP
"Cheer up, things could get worse..so I cheered up and, sure enough, things got worse!"
|
Re: K7QO Legacy Projects and Files [OT and Long]
Chuck:
I, too, have benefited from your postings and videos, especially on Muppet construction and the 1W-5W assembly manuals. It's too bad that every kit doesn't use the build-and-test paradigm. I also think most people know how I feel about copying/downloading material without permission, so we share that sentiment.
I'm in Jasper, AL, Canada, now so don't have the resources to download your posts/videos. I hope you'll leave them up until after the 21st!
Tnx again, Chuck.
72,?Jack, W8TEE
toggle quoted message
Show quoted text
On Monday, September 9, 2019, 10:49:13 PM MDT, chuck adams <chuck.adams.k7qo@...> wrote:
Gang,
I lost my 1TB SSD drive this last week and I have been hunkered down
trying to restore everything to its original state as best I can.
Because of the Raspberry Pi 4 project I had not been doing the usual
due diligence in backups and for that I am hoping that I have not lost
too much.? You know the drill.? I wrote a program for a computer company
a long time ago to erase disks before they were drilled, compressed and
shreaded to micro-particle sizes and then incinerated at solar
temperatures for final state for disposal.? I also wrote a recovery
routine and that I am thankful for as I can recover most, if not all, of
my files.? It is just time consuming.
The good news that I am going through 40GB of backups in the process to
hopefully save some time.? I found some stuff that I had forgotten about
or thought I had deleted.
Before I give the list so far, please read the fine print on my web
page.? It is important for my mental state of mind.
1.? The CW books.? I will put some of the old CW books on my web page.
I have the title and the speed listed.? You should know who the author
is, so please don't ask me.? The speeds are for the whole disk.? Do not
ask me if I can do another speed.? You adjust.? These books should help
you practice 'copy in your head', which isn't a big deal as people make
it out to be.? I prefer to know how you do at hard copy.? I think I can
keep them out there for some time, but you had better download them
today.? No guarantees.? I think I have unlimited space, but I'll do
them until the web provider sends me a bill.
People ask me why I quit doing the project.? I was standing at a
hamfest talking to someone that I knew.? He had a buddy with him.
He introduced me to his buddy and then said.? "Chuck used to do the
books in Morse code.? Like the one I bought and gave you a copy of."
And he was wondering why I quit???? Duh.
I am putting the code in ISO format for each book and this includes
the text files.? So they are large.? They will remain the same size.
I am not going to redo them for you.? AND, after I upload the ISO
file it is deleted from my drives and will not ever return.? Also.
You do not have the right(s) to copy to another site and provide
them now or EVER.? Please.? And people wonder why I have an attitude.
Now you know.
2.? The PDF documents for build projects I will post as soon as I
can find them and get time to put them online.? I got an email yesterday
from someone that was wondering where the hx108.pdf document went.? I
had the thing up there for almost a year.? He should have downloaded.
I am not a library and I get tired of my work and I do reserve the right
to take it down.? Either get the project done or download the material.
So.? As a final parting shot.? Do not cross post this to any other site.
Do not copy the material for purposes other than your own private use.
Do not put the files on your site or other sites.? I will not be a happy
camper.
I will not list nor will I allow anyone to create a list of my material
and post it.? Let them go to and do the work
themselves.? If they aren't interested, then so be it.
So, keep monitoring my web page.? I need the hits.? I am not going to
advertise here or anywhere else as to the material placed online.? And
I do reserve the right to discontinue if I feel that I am being used or
if some one pushes me in the wrong direction.? No guarantees and the
sale is final..
enjoy while you can,
chuck, k7qo
|
Unique chance to grab unassembled genuine kit on eBay:
(I am not the seller)
Petr, OK1RP
|
Re: K7QO Legacy Projects and Files [OT and Long]
Hi Chuck,
Thanks for the heads-up. I bookmarked your site and then downloaded several things of interest to me. I will look in from time to time to see what you have on there.
There is a Swedish ham with a lot of interesting, useful, and even inspirational content on his site. One day I went there to review something and his site was *gone*. It soon reappeared on a new service. I have my own copies now. I am dealing with yours the same way.
I understand how you feel about some violations. I took a lot of flak for refusing to use illegal copies of commercial or shareware software. -shrug- but I do sleep well:)
73,
Bill KU8H
toggle quoted message
Show quoted text
On 9/10/19 3:43 AM, chuck adams wrote: The problem was not with the code course.? It was with the Morse
code books....
thanks,
On 9/10/19 12:21 AM, Mike Carden - VK1MC wrote:
I'm not sure you ought to be so quick to condemn that guy. In the Manual
for the Code course, you say:
"Also make a backup copy of
the CD if you have a CD burner on a
computer. Make copies and give them to
kids, relatives, friends, and even your
enemies (drive them insane)."
--
bark less - wag more
|
|
|
Re: Raspberry Pi 4 Course
Thank you Alan!
73
Dave, NI9M
Silvis, IL
toggle quoted message
Show quoted text
------ Original Message ------ From: "Alan Jones" <oalanjones@...> To: [email protected]Sent: 9/10/2019 10:42:10 AM Subject: Re: [qrp-tech] Raspberry Pi 4 Course Dave,
Go to youtube and search for k7qo or try this link:
Alan, N8WQ
On Tue, 10 Sep 2019 11:34:11 -0400, Dave Belville <davebelville@...> wrote:
Alan/Chuck,
I would be interested in following a Rasp Pi Course. Can someone tell me how?
Thanks
73
Dave, NI9M
------ Original Message ------
From: "Alan Jones" <oalanjones@...>
To: [email protected]
Sent: 9/10/2019 10:08:01 AM
Subject: [qrp-tech] Raspberry Pi 4 Course
Chuck,
Just wanted to let you know how much I enjoy following along with your Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C, Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am having fun learning how to use it. Today I took the plunge and ordered a Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to use it for amateur radio projects. I am afraid that I am slowly moving towards the darkside and except for CW will probably be going totally digital here, lol. The first program I will install after getting my Pi 4 will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Re: Raspberry Pi 4 Course
Dave,
Go to youtube and search for k7qo or try this link:
Alan, N8WQ
toggle quoted message
Show quoted text
On Tue, 10 Sep 2019 11:34:11 -0400, Dave Belville <davebelville@...> wrote: Alan/Chuck,
I would be interested in following a Rasp Pi Course. Can someone tell me how?
Thanks
73
Dave, NI9M
------ Original Message ------
From: "Alan Jones" <oalanjones@...>
To: [email protected]
Sent: 9/10/2019 10:08:01 AM
Subject: [qrp-tech] Raspberry Pi 4 Course
Chuck,
Just wanted to let you know how much I enjoy following along with your Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C, Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am having fun learning how to use it. Today I took the plunge and ordered a Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to use it for amateur radio projects. I am afraid that I am slowly moving towards the darkside and except for CW will probably be going totally digital here, lol. The first program I will install after getting my Pi 4 will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Re: Raspberry Pi 4 Course
Raspberry Pi 4 Course by K7QO:
Start here:
Regards,
Ken, KM4NFQ "Not Fully Qualified"
toggle quoted message
Show quoted text
On Tue, Sep 10, 2019 at 11:34 AM Dave Belville <davebelville@...> wrote:
Alan/Chuck,
I would be interested in following a Rasp Pi Course. Can someone tell me
how?
Thanks
73
Dave, NI9M
------ Original Message ------
From: "Alan Jones" <oalanjones@...>
To: [email protected]
Sent: 9/10/2019 10:08:01 AM
Subject: [qrp-tech] Raspberry Pi 4 Course
Chuck,
Just wanted to let you know how much I enjoy following along with your Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C, Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am having fun learning how to use it. Today I took the plunge and ordered a Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to use it for amateur radio projects. I am afraid that I am slowly moving towards the darkside and except for CW will probably be going totally digital here, lol. The first program I will install after getting my Pi 4 will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Re: Raspberry Pi 4 Course
Greetings,
I would like to point out two CW Ham Radio packages that can be
installed on a Raspberry Pi:
ebook2cw
and
morse.
Source:
Regards,
Ken, KM4NFQ "Not Fully Qualified"
toggle quoted message
Show quoted text
On Tue, Sep 10, 2019 at 11:08 AM Alan Jones <oalanjones@...> wrote:
Chuck,
Just wanted to let you know how much I enjoy following along with your
Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C,
Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am
having fun learning how to use it. Today I took the plunge and ordered a
Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to
use it for amateur radio projects. I am afraid that I am slowly moving
towards the darkside and except for CW will probably be going totally
digital here, lol. The first program I will install after getting my Pi 4
will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Re: Raspberry Pi 4 Course
Alan/Chuck,
I would be interested in following a Rasp Pi Course. Can someone tell me how?
Thanks
73
Dave, NI9M
toggle quoted message
Show quoted text
------ Original Message ------ From: "Alan Jones" <oalanjones@...> To: [email protected]Sent: 9/10/2019 10:08:01 AM Subject: [qrp-tech] Raspberry Pi 4 Course Chuck,
Just wanted to let you know how much I enjoy following along with your Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C, Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am having fun learning how to use it. Today I took the plunge and ordered a Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to use it for amateur radio projects. I am afraid that I am slowly moving towards the darkside and except for CW will probably be going totally digital here, lol. The first program I will install after getting my Pi 4 will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Chuck,
Just wanted to let you know how much I enjoy following along with your Raspberry Pi 4 Course.
I especially like your pieces of history you are throwing in about C, Fortran, VAX computer, etc. It is very interesting.
I ordered a Raspberry Pi Zero W kit with camera about 2 weeks ago and I am having fun learning how to use it. Today I took the plunge and ordered a Raspberry Pi 4 kit with 4G of RAM. I am looking forward to learning how to use it for amateur radio projects. I am afraid that I am slowly moving towards the darkside and except for CW will probably be going totally digital here, lol. The first program I will install after getting my Pi 4 will be fldigi.
Hope you are having a great day Chuck!
Alan, N8WQ
|
Re: K7QO Legacy Projects and Files [OT and Long]
On Tue, Sep 10, 2019 at 12:49 AM chuck adams <chuck.adams.k7qo@...> wrote:
I lost my 1TB SSD drive this last week and I have been hunkered down
trying to restore everything to its original state as best I can.
I have heard that those large (1TB+) Solid State drives don't last very long? That is why I make backups on DVDs. I wrote a small shell script that tells me how big the current working directory is, and when that gets to 4.5GB, I rename it to yyyymmdd-backup/ then make an ISO image of it, and burn it to a DVD. Then I start a new current working directory and keep on trucking. Last week my DVD drive broke as I was getting ready to burn a backup. A quick trip to the local computer store with $25 got me up and going again with a new DVD drive. The funny thing is, I rarely look back. I have stacks of backups, but I only look for something when I cannot find it on the Internet anymore. Go figure. With the Internet, the only constant is change. Thank you for everything you do for the CW community, Chuck. I for one appreciate it tremendously. Regards, Ken, KM4NFQ "Not Fully Qualified" Because of the Raspberry Pi 4 project I had not been doing the usual
due diligence in backups and for that I am hoping that I have not lost
too much. You know the drill. I wrote a program for a computer company
a long time ago to erase disks before they were drilled, compressed and
shreaded to micro-particle sizes and then incinerated at solar
temperatures for final state for disposal. I also wrote a recovery
routine and that I am thankful for as I can recover most, if not all, of
my files. It is just time consuming.
The good news that I am going through 40GB of backups in the process to
hopefully save some time. I found some stuff that I had forgotten about
or thought I had deleted.
Before I give the list so far, please read the fine print on my web
page. It is important for my mental state of mind.
1. The CW books. I will put some of the old CW books on my web page.
I have the title and the speed listed. You should know who the author
is, so please don't ask me. The speeds are for the whole disk. Do not
ask me if I can do another speed. You adjust. These books should help
you practice 'copy in your head', which isn't a big deal as people make
it out to be. I prefer to know how you do at hard copy. I think I can
keep them out there for some time, but you had better download them
today. No guarantees. I think I have unlimited space, but I'll do
them until the web provider sends me a bill.
People ask me why I quit doing the project. I was standing at a
hamfest talking to someone that I knew. He had a buddy with him.
He introduced me to his buddy and then said. "Chuck used to do the
books in Morse code. Like the one I bought and gave you a copy of."
And he was wondering why I quit??? Duh.
I am putting the code in ISO format for each book and this includes
the text files. So they are large. They will remain the same size.
I am not going to redo them for you. AND, after I upload the ISO
file it is deleted from my drives and will not ever return. Also.
You do not have the right(s) to copy to another site and provide
them now or EVER. Please. And people wonder why I have an attitude.
Now you know.
2. The PDF documents for build projects I will post as soon as I
can find them and get time to put them online. I got an email yesterday
from someone that was wondering where the hx108.pdf document went. I
had the thing up there for almost a year. He should have downloaded.
I am not a library and I get tired of my work and I do reserve the right
to take it down. Either get the project done or download the material.
So. As a final parting shot. Do not cross post this to any other site.
Do not copy the material for purposes other than your own private use.
Do not put the files on your site or other sites. I will not be a happy
camper.
I will not list nor will I allow anyone to create a list of my material
and post it. Let them go to and do the work
themselves. If they aren't interested, then so be it.
So, keep monitoring my web page. I need the hits. I am not going to
advertise here or anywhere else as to the material placed online. And
I do reserve the right to discontinue if I feel that I am being used or
if some one pushes me in the wrong direction. No guarantees and the
sale is final..
enjoy while you can,
chuck, k7qo
|
Re: K7QO Legacy Projects and Files [OT and Long]
The problem was not with the code course. It was with the Morse
code books....
thanks,
toggle quoted message
Show quoted text
On 9/10/19 12:21 AM, Mike Carden - VK1MC wrote: I'm not sure you ought to be so quick to condemn that guy. In the Manual
for the Code course, you say:
"Also make a backup copy of
the CD if you have a CD burner on a
computer. Make copies and give them to
kids, relatives, friends, and even your
enemies (drive them insane)."
|
Re: K7QO Legacy Projects and Files [OT and Long]
Thanks Chuck. I think you know that the Amateur community greatly appreciates your lifetime of excellent contributions to our collective knowledge. I am personally grateful for the learning assets that you have worked so hard to create and share. People ask me why I quit doing the project. I was standing at a
hamfest talking to someone that I knew. He had a buddy with him.
He introduced me to his buddy and then said. "Chuck used to do the
books in Morse code. Like the one I bought and gave you a copy of."
And he was wondering why I quit??? Duh.
I'm not sure you ought to be so quick to condemn that guy. In the Manual for the Code course, you say: "Also make a backup copy of the CD if you have a CD burner on a computer. Make copies and give them to kids, relatives, friends, and even your enemies (drive them insane)." Seems like he possibly thought sharing was okay. Anyway, if you are concerned about the cost of making available all of the wonderful content you have created, may I suggest reaching out right here, to the people who care. Many zero-cost (to you) mechanisms exist for keeping information available to all. -- MC VK1MC
|
Re: K7QO Legacy Projects and Files [OT and Long]
Hi Chuck, There are a couple of backups? of your site on the "wayback machine" from this year that might help you as well as 20 other copies going back to 2012. Cheers, Will ZL1TAO On 10/09/19 4:49 PM, chuck adams wrote: Gang,
I lost my 1TB SSD drive this last week and I have been hunkered down
trying to restore everything to its original state as best I can.
Because of the Raspberry Pi 4 project I had not been doing the usual
due diligence in backups and for that I am hoping that I have not lost
too much.? You know the drill.? I wrote a program for a computer company
a long time ago to erase disks before they were drilled, compressed and
shreaded to micro-particle sizes and then incinerated at solar
temperatures for final state for disposal.? I also wrote a recovery
routine and that I am thankful for as I can recover most, if not all, of
my files.? It is just time consuming.
The good news that I am going through 40GB of backups in the process to
hopefully save some time.? I found some stuff that I had forgotten about
or thought I had deleted.
<Snip>
|
K7QO Legacy Projects and Files [OT and Long]
Gang,
I lost my 1TB SSD drive this last week and I have been hunkered down
trying to restore everything to its original state as best I can.
Because of the Raspberry Pi 4 project I had not been doing the usual
due diligence in backups and for that I am hoping that I have not lost
too much. You know the drill. I wrote a program for a computer company
a long time ago to erase disks before they were drilled, compressed and
shreaded to micro-particle sizes and then incinerated at solar temperatures for final state for disposal. I also wrote a recovery routine and that I am thankful for as I can recover most, if not all, of
my files. It is just time consuming.
The good news that I am going through 40GB of backups in the process to
hopefully save some time. I found some stuff that I had forgotten about
or thought I had deleted.
Before I give the list so far, please read the fine print on my web page. It is important for my mental state of mind.
1. The CW books. I will put some of the old CW books on my web page.
I have the title and the speed listed. You should know who the author
is, so please don't ask me. The speeds are for the whole disk. Do not
ask me if I can do another speed. You adjust. These books should help you practice 'copy in your head', which isn't a big deal as people make it out to be. I prefer to know how you do at hard copy. I think I can keep them out there for some time, but you had better download them today. No guarantees. I think I have unlimited space, but I'll do
them until the web provider sends me a bill.
People ask me why I quit doing the project. I was standing at a
hamfest talking to someone that I knew. He had a buddy with him.
He introduced me to his buddy and then said. "Chuck used to do the
books in Morse code. Like the one I bought and gave you a copy of."
And he was wondering why I quit??? Duh.
I am putting the code in ISO format for each book and this includes
the text files. So they are large. They will remain the same size.
I am not going to redo them for you. AND, after I upload the ISO
file it is deleted from my drives and will not ever return. Also.
You do not have the right(s) to copy to another site and provide
them now or EVER. Please. And people wonder why I have an attitude.
Now you know.
2. The PDF documents for build projects I will post as soon as I
can find them and get time to put them online. I got an email yesterday
from someone that was wondering where the hx108.pdf document went. I
had the thing up there for almost a year. He should have downloaded.
I am not a library and I get tired of my work and I do reserve the right
to take it down. Either get the project done or download the material.
So. As a final parting shot. Do not cross post this to any other site.
Do not copy the material for purposes other than your own private use.
Do not put the files on your site or other sites. I will not be a happy
camper.
I will not list nor will I allow anyone to create a list of my material
and post it. Let them go to and do the work
themselves. If they aren't interested, then so be it.
So, keep monitoring my web page. I need the hits. I am not going to
advertise here or anywhere else as to the material placed online. And
I do reserve the right to discontinue if I feel that I am being used or
if some one pushes me in the wrong direction. No guarantees and the
sale is final..
enjoy while you can,
chuck, k7qo
|
Looking for more gain for use with SA612/LM386 receivers, I found this version by JF1OZL. *
Emacs!
Bread-boarded it and did some basic measurements with the feedback resistor Rf at 10 Ohms
With a bench supply voltage of 9V and at a frequency of 1 kHz, got the following results.
Input: 0.00275 Vpp** output voltage was 7 Vpp across a 7.5 Ohm 5W resistor, about 800 mW.
That calculated to ~69 dB (Data sheet is 43 dB)
The output looked clean with no apparent spurious stuff.
* Also another version from LA3ZA which used a few more parts.
** At 9V supply, the output starts clipping above this value from the function generator
|
Re: "The Electronics of Radio" Problem
Yes, both measurements are peak-to-peak voltages.
Thank you very much Nick for the great explanation. It's the internal 50 ohm resistance from the power source (function generator) that I was missing.
Next step is to measure this calculated number. Of course DC measurements are pointless. But I thought the antenna analyzer should be able to do it. Changed the antenna analyzer's frequency until reactance (X) was zero which append at 7.192MHz and got a resistance (R) of 14.1 Ohm. If you do a reverse calculation, the voltage across the LC at resonance would be 220mV. Knowing how hard it was to adjust the variable capacitor it's quite in the tolerance of my ability to adjust the capacitor for resonance.
Lab work successful. I learned a lot. Thank again Nick. Also thanks to Steve and Chuck for the great additional questions.
Claus
|
Re: "The Electronics of Radio" Problem
Well, it can be in any units if kept consistent. I think it said pp in one
instance and didn¡¯t specify in the other. So I figured we were staying with
p-p.
I do normally think though, that when someone just says ¡®volts¡¯ that RMS
should be assumed.
73
Nick
toggle quoted message
Show quoted text
On Sun, Sep 8, 2019 at 11:55 AM Chuck Carpenter <w5usj@...> wrote: Nick,
The voltage is 1 Vpp. Should that be converted to RMS (0.707)?
Chuck, W5USJ (ex K2OFN)
ARCI 5422, SKCC 19956
EM22cv, Rains Co., Texas
|
Jack
Alan N8WQ
Ken KM4NFQ
Nick Kennedy