LOL LOOK AT THE SCOPE. Especially when he says it looks good

[kopcicle]

Admiral Hopper was the one who found an actual bug in a computer program. In a computer that filled a gymnasium she did find a moth caught in a relay, hence the term BUG in a programs was born.

Mostly correct , it was a "partial bug" wing of a moth to be exact. Although it gets popularized as the first bug it is not.
Something she is to be credited with is the first "compiler" (that is even a bit of a stretch) and the first "patch"

A common misconception is that a software bug is called a bug because of an actual bug – a moth – that got stuck in Harvard University’s Mark II calculator in 1947. The story goes that Grace Hopper found it, taped it inside a logbook with the words “First actual case of bug being found”.
In reality Grace herself didn’t find the bug – somebody else from the team did – nor did they coin the term bug because of that event.

American engineers have been calling small flaws in machines “bugs” for over a century. Thomas Edison talked about bugs in electrical circuits in the 1870s. When the first computers were built during the early 1940s, people working on them found bugs in both the hardware of the machines and in the programs that ran them.

Lastly COBOL "common business-oriented language". COBOL was a programming language implemented as the first phase of a beginning , middle and end solution. Grace Hopper was a significant part of the committee that created COBOL but not the sole inventor.
Only the first phase of COBOL was ever written having never progressed as far as the middle and advanced stages. So an interim solution that has spanned 70+ years ...

Built on previous research were projects that were all Grace Hopper that deserve all due credit.
The A-0 , A-1, A-2 compiler
built on
Flow-matic (a Grace Hopper project that progressed to "Business Language version 0" then COBOL

OKAY
Done splitting hairs here. The point is we now stand on the shoulders of giants. Grace Murry Hopper was one of them .

 

[543_Dallas]

so ...

13.8 X 4A = 55.2W / 60% (being generous even for a FET)= 33.12~

Yup , unbelievable. *

Now it is possible to get much better efficiency ...
http://www.classeradio.com/
but this is a very specific exception.

Let's go back to school for just a bit .

Voltage multiplied by current equal watts.
A BJT in a tuned, single ended circuit can approach 60% efficiency.
There are other current drains on a transceiver so approximately 50% efficiency is an acceptable rule of thumb.
Although a MosFET may have slightly better efficiency the above still holds reasonably true.

Bird, Dosey, MFJ, it doesn't really matter. The above is what you get.

*I wonder what the thermal load is on the surface area of that TO220 mounting

I'm not defending the 70 watt cobra 29. Its a turd. I see the same math used over and over again online when the output of a cb radio or cb amplifier is brought into question. Almost every time they are comparing DC input voltage and amperage to peak envelope power. The math is good if you were comparing it to average power out of the transmitter but it doesn't work with pep, especially on AM.

If the radio is transmitting a 100% modulated sine wave the average reading watt meter and the current meter on the power supply will not change much at all from 0% to 100% modulation. The pep power will increase 4 times but the current draw does not. Remember this is AM and the negative peaks are going down to the baseline as the positive peaks rise. 70 watt cobra 29 was producing a 7 watt carrier and slamming the 20 watt scale in average mode. Your math says this is possible.


Post was edited to change "pep power" to "peak envelope power". Thanks to all that would have pointed that out.

 

[kopcicle]

...never fucking mind

 

[loosecannon]

"One accurate measurement is worth a thousand expert opinions" - Adm Grace Murray Hopper

did you used to use this as a signature?
LC

 

[543_Dallas]

...never fucking mind

Why are you being this way? The last time I brought this up was when someone questioned the output of an 8877 cb amp. I was ignored. I asked the guy to do a simple test with his HF rig in AM mode and try his math with his own equipment. He ignored me then and you're pissed now. If you're going to elmer the cbers please do it correctly or explain to me why I'm wrong. It's an open forum after all.

 

[Tallman]

Mostly correct , it was a "partial bug" wing of a moth to be exact. Although it gets popularized as the first bug it is not.
Something she is to be credited with is the first.........

Whatever.

 

[OldTech03]

so ...

13.8 X 4A = 55.2W / 60% (being generous even for a FET)= 33.12~

Yup , unbelievable. *

Now it is possible to get much better efficiency ...
http://www.classeradio.com/
but this is a very specific exception.

Let's go back to school for just a bit .

Voltage multiplied by current equal watts.
A BJT in a tuned, single ended circuit can approach 60% efficiency.
There are other current drains on a transceiver so approximately 50% efficiency is an acceptable rule of thumb.
Although a MosFET may have slightly better efficiency the above still holds reasonably true.

Bird, Dosey, MFJ, it doesn't really matter. The above is what you get.

*I wonder what the thermal load is on the surface area of that TO220 mounting

In response to the overwhelming number of videos showing crazy forward power coming from radios that barely develope enough power to get out of there own way I thought it would be fun for some of the newbies to see what affect audio has on wattmeter readings. So below I hooked my 6060 up to a small average reading meter that I modified to be sensitive enough to display the output of the generator essentially full scale is less than 1 watt. The real teaching moment here is to show that 99% of the time what you seeing in these videos is nothing more than rectified audio and NOT RF!. As you can see over 60% of the forward power is the result of the audio component, Again NOT RF.

OldTech

 

[Onelasttime]

Man you could see the boxcars clearly!

On top of that, it is a 20Mhz scope working on a 27Mhz radio?!?!?!

First time that see's an SWR higher than 1.5:1 maybe less it is going to go "pop"!

 

[Onelasttime]

Mostly correct , it was a "partial bug" wing of a moth to be exact. Although it gets popularized as the first bug it is not.
Something she is to be credited with is the first "compiler" (that is even a bit of a stretch) and the first "patch"

A common misconception is that a software bug is called a bug because of an actual bug – a moth – that got stuck in Harvard University’s Mark II calculator in 1947. The story goes that Grace Hopper found it, taped it inside a logbook with the words “First actual case of bug being found”.
In reality Grace herself didn’t find the bug – somebody else from the team did – nor did they coin the term bug because of that event.

American engineers have been calling small flaws in machines “bugs” for over a century. Thomas Edison talked about bugs in electrical circuits in the 1870s. When the first computers were built during the early 1940s, people working on them found bugs in both the hardware of the machines and in the programs that ran them.

Lastly COBOL "common business-oriented language". COBOL was a programming language implemented as the first phase of a beginning , middle and end solution. Grace Hopper was a significant part of the committee that created COBOL but not the sole inventor.
Only the first phase of COBOL was ever written having never progressed as far as the middle and advanced stages. So an interim solution that has spanned 70+ years ...

Built on previous research were projects that were all Grace Hopper that deserves all due credit.
The A-0 , A-1, A-2 compiler
built on
Flow-matic (a Grace Hopper project that progressed to "Business Language version 0" then COBOL

OKAY
Done splitting hairs here. The point is we now stand on the shoulders of giants. Grace Murry Hopper was one of them .

The first langes I learned growing up around 1982 was COBOL, BASIC, QW-Basic, ASL-400, Fortran and MS-DOS. By High School 1988 I got interested in girls and computers went by-by until college for me. I keep telling myself I am going to learn to code again but always find a way to not get around to it.

 

[Onelasttime]

"Y'know, I can understand this type of radio workmanship forty years ago. With no information highway or a consensus of proper convention or protocols. But for this ignorance to continue despite the overwhelming information available to the contrary, these ignorant`concepts and delusions still continue.

He seems to be concerned with only the total power output and disregards everything else. Wonder if he understands different harmonics and how they occur? Or the life expectancy of the MOSFET? Did anyone else notice that he had spread the 54mhz trap coil? He spent - how much - on the two Bird meters? What - ~$1200? Yet he isn't aware of a little knowledge that is free that would turn his quality of workmanship around 180 degrees. How does he remain this clueless and still have customers? Boggling - isn't it?

It isn't stupidity; just ignorance.
Now if he learns better and continues with his present methods; then it is stupidity."

Love it!!! I let myself get a bit too upset at times because of either ignorance or half truths take your pick. I remeber how hard it was to learn about cutting edge stuff. I had to write letters to Doctors and Scientist. You had to find some obsecure group of guys and either meet up or fax things back and forth because one guy knew a guy that knew a guy that had a copy of a book you wanted to read but could not find. You might call a guy up and if you sounded like someone that was a peer or at least on the same path they might fax you the material or mail you a book with the idea you would mail it back after you read it.

Clipping articles out of electronic magazines and such and making your own 3 ring binder with electronic projects, coding fixes, gunsmithing or reloading info etc.....

 

[Handy Andy]

"

Y'know, I can understand this type of radio workmanship forty years ago.

....if you sounded like someone that was a peer or at least on the same path they might fax you the material or mail you a book with the idea you would mail it back after you read it.

Clipping articles out of electronic magazines and such and making your own 3 ring binder with electronic projects, coding fixes, gunsmithing or reloading info etc.....

So you're the one that took all my RADIO Electronics, Popular Electronics and my 1975-1984 Radio Shack Catalog Collection!

 

[Robb]

I think what I said pretty much summed up what we see.
Of course, you can feel free to embellish further if you see more than I did.

There it is, an O'scope looking right at you, me, and that tech(?!?); and we all saw different things. Thing is, that scope isn't opinionated. It is a gauge, a meter, a means to define electrical activity in a very strict form for us to evaluate. It has done its part; now it is our turn to interpret.

Apparently. that tech(?!?) saw the fruit of his labors and was pleased.
I think that the majority of us saw a 27mhz square wave generator with as yet undisclosed harmonic content that used to be a CB radio.

Think more than any point presented, is his own apparent disregard of what he is ultimately trying to accomplish. I think that I am trying to get inside his head here a bit. Please correct me if I am wrong. But if 'big modulation and large swing' was his only goal; then he reached it. My gripe is that he did that in total disregard of any other first order factors that should have been considered.

The ONLY thing he proved to me is that he needs to go back, and do it again, and get it right.

 

[Tallman]

Once again a 20 Mhz scope will work just fine on 27 Mhz and higher frequencies.
The 20 Mhz refers to BANDWIDTH not the maximum usable frequency.
It is more akin to a low resolution camera VS a high definition 4D Video camera.
What you would not see is something you would need a spectrum analyzer to identify.
You just end up spending more money for bandwidth and not really getting the benefit.
Mine is the OS-2 version of this scope and it is even older than the one pictured.

 

[rabbiporkchop]

Once again a 20 Mhz scope will work just fine on 27 Mhz and higher frequencies.
The 20 Mhz refers to BANDWIDTH not the maximum usable frequency.
It is more akin to a low resolution camera VS a high definition 4D Video camera.
What you would not see is something you would need a spectrum analyzer to identify.
You just end up spending more money for bandwidth and not really getting the benefit.
Mine is the OS-2 version of this scope and it is even older than the one pictured.

Will work to a point, but how accurately?

 

[Tallman]

Will work to a point, but how accurately?

Just about accurate as any other and dependent upon the skill of the operator and calibration. You should use a Frequency Counter for frequency readings. I will guarantee you any body that does alignments using scope frequency reading for setting the local oscillator will hand you back a useless door stop.
The Oscilloscope is best used for observation of wave forms condition and phase angles in relationship to other wave forms. Voltage readings are relative.