Need advice!

[noyb72]

Sorry mopar

The one and only thing I know for sure in that entire post, and have know for 15 years is that modulation is the percentage of information reproduced expressed in degrees of the sign wave. I understand you have taught yourself mostly on the net, do me a favor and google modulation. The class of amp indicates the percentage of modulation. Class a = 360 degrees. Class AB>180 but <360. Class b= 180. Class C<180. Class D=0.

If what lords is saying by saying "over 100% modulation" is that the modulated input drives output power to a level that is greater than double the carrier power level then the term modulation shouldn't be there. I guess it is better to say that the jargon is different.

The modulation of a transmitter will be the exact same, expressed in degrees or as a percentage, weather you are outputing just above dead key, or if your swinging up as hot as the amp circuit will be stable. Distortion comes when the increased power gets to a point where the amplifier circuit is overdriven and the modulated signal breaks down (bad,bad,bad if you are underwater and using a microphone for your eyes!) or if, because of the design of the circuit overmodulation occurs. ( usually only in class a, or in a class A/B of high percentege.) I have literally put my life on this electical fact for 6 of the last 10 years. If the jargon is different, GREAT!! Then I think I understand where all my confusion comes from. But if you look at any text book ( I personaly like the Navy NEETS mods,) it will explain to you the exact thing I just did.

Thanks again for all your help
Ron

 

[noyb72]

Wait, I just reread your post. I got it. You said biasing has to do with when it is "on" and you are exactly right although i have NEVER heard someone put it that way. What I think you are not understanding is that the amp is "on" when it is replicating information (modulating,) during the time the amp is "off" if you will there is still information to be modulated, and because the amp is "off" the information is lost or "clipped." The period that the amp is "on" is expressed in degrees as I stated above. That still doesn't change the fact that swing has nothing at all to do with modulation other that in certain conditions it can cause overmodulation.

Thanks again
Ron

 

[mopar2ya]

I understand you have taught yourself mostly on the net, do me a favor and google modulation.

Google it yourself you pompous...... [Mopar shudders with anger and regains his composure.]

Yes I am offended. I am done helping you. Someone with a degree can cut your erroneous posts to shreds.

Geez I hope freecell wanders in here. If he takes the time to wipe you out line by line, you better have a spare mouse handy. Your wheel is gonna wear out.

Oh, and go back and re-read that post of mine. I am not "taught mostly on the net". Just because I give credit to some really nice folks who have pointed me in the direction of formal literature you ASSume I am an idiot. GRRRR!

The one and only thing I know for sure in that entire post, and have know for 15 years is that modulation is the percentage of information reproduced expressed in degrees of the sign wave. The class of amp indicates the percentage of modulation. Class a = 360 degrees. Class AB>180 but <360. Class b= 180. Class C<180. Class D=0.

Interesting. I will do my best to remember that quote as the quintessential example of how you should never take information you find on the net for gospel. The internet is filled with misinformation written by folks who claim to know what they are talking about. GRRRR! Your mess is now someone else's to clean up.

Mopar

 

[lords]

Geez I hope freecell wanders in here. If he takes the time to wipe you out line by line, you better have a spare mouse handy. Your wheel is gonna wear out.


ya where is he when you need him...
and yes google is your best friend....
and quit spamming just to get posts damit.lol

your starting to remind me of JOHNNY '5' is alive..lol

 

[Captain Kilowatt]

Sorry mopar

The one and only thing I know for sure in that entire post, and have know for 15 years is that modulation is the percentage of information reproduced expressed in degrees of the sign wave. I understand you have taught yourself mostly on the net, do me a favor and google modulation. The class of amp indicates the percentage of modulation. Class a = 360 degrees. Class AB>180 but <360. Class b= 180. Class C<180. Class D=0.

:shock: Man, just when I thought I heard it all. :roll:

 

[mopar2ya]

Ahh. Lookie there. QRN wanders in. Remember that name? I mentioned him in the post on that other forum that made me an idiot in your mind.... You are lucky he was too stunned to say anything rude. In case you are wondering... NO! I did not PM him or anyone else to come to my rescue.

[SNIP]

Thanks for the props guys. In all honesty, I am not a smart as some of my posts would lead you to believe. I have no formal electronics education. What I have done is educate myself by extensive reading, and a bunch of experimenting. Whenever I post something, there is a ton of thought that goes into the post. I try to be painfully accurate. Some of what I know is from RF related books, and some is from really smart forum contributers. I will drop some names here for you to watch. Most of them are on other forums like WWRF, and the temporarily out of commission CB Tricks.

Peakaboo, Pain, freecell(228), Ken White, W5LZ, Beetle, QRN, AB7IF, and nomadradio in no particular order, except the first two names. Peakaboo and Pain will always be at the top of any list I made that pertained to where I learned any RF knowledge I happen to have. They have helped me immensely and have become two of my most appreciated friends. I can't tell you how fortunate I am to be able to consult them when I am floundering. That list of people is comprised of folks that flat out make me feel stupid. If I could just brush the surface of what they know, I would be a very impressive fellow indeed. Read every word they post twice, you will want to remember every detail.

Next are book folks in no particular order.

Walter Maxwell, L. B. Cebik, Norm Dye, Helge Granberg, and Lou Franklin

There are many more I am sure I am forgetting, but that is a good start.

Mopar

 

[Captain Kilowatt]

Ahh. Lookie there. QRN wanders in. Remember that name? I mentioned him in the post on that other forum that made me an idiot in your mind.... You are lucky he was too stunned to say anything rude. In case you are wondering... NO! I did not PM him or anyone else to come to my rescue.

Uuuhhh.......I was just wandering around the forum and strolled by here as I do once or twice a day,more if I am on my days off which I am today. People know me for NOT jumping and ripping someone about something but I have been known to express myself subtly. I can't believe where the idea that % modulation is related to the class of operation an amp is operated in ever came from.Trust me,as a commercial broadcast engineer for 22 years maintaining and installing both AM and FM radio stations as well as VHF/UHF radio systems I am quite familiar with modulation schemes and amplifier classes and one has absoutely NOTHING to do with the other.

BTW mopar2ya thanks for the vote of confidance. As for the others you mentioned,I have much respect for them as well.

 

[W5LZ]

I think part least part of the 'problem' is a definition of terms, another part is how those terms are used in a particular instance. For instance. The term 'on' or 'off' isn't an either or thingy, it's also a matter of degree. Except in 'special' circumstances like a class 'D' amplifier. That thing is either on or off, nothing in between. (Great for a 'pulsing' type signal such as CW, absolutely worthless for voice cuz it can't be "modulated" at all.)

Power Amplifiers. What comes out is a larger version of what goes in, period. 'GIGO', like it or not. An amplifier has no idea that there is a difference between 'parts' of a signal fed to it (carrier or modulation). Any tailoring of audio is done before the power amplification stages, or in between, but not during.

'S' meters.
I won't get into how they are 'calibrated', there's ~supposed~ to be standards but they certainly are not followed very much.
'S' meters measure the strength of the received signal and because of how they are calibrated, 'assign' that particular strength a value as displayed on the meter. They can tell you 'how much' but can't tell you anything about how that value is determined. As in, how far away was it coming from? That part is the responsibility of the 'computer' between your ears, which is supposed to tell you how 'good' or 'bad' the 'S' reading is. That process is 'relative' and depends on the accuracy of that 'computer'. From personal experience I've found that the 'accuracy' is of such a wide range that it's almost a joke. Those 'S' readings are only of any value to the receiving station, and not really much value there. There's a -humongus- load of variables in those readings.

Theory.
After you wipe all the 'poo-poo' off of it, and if it comes from a reliable source, it means you don't have to make all those 'same-old' mistakes that somebody else made to formulate that 'theory'. There are two factors that have to be considered. Just how 'reliable' is the source, and can you understand what the @#$$ they said? The first one is a whole lot easier to figure out than the second one! NO disrespect intended, but I've only seen two of those 'reliable sources' post on the internet (not here, unfortunately). The only ones I honestly can say don't post on the internet at all, are those that are dead, so what I've seen doesn't mean a lot, you know?
- 'Doc

PS - The only reason QRN included my 'name' in those he dropped was because, sometimes, it's just too nasty to hold onto.

 

[mopar2ya]

NO disrespect intended, but I've only seen two of those 'reliable sources' post on the internet (not here, unfortunately). The only ones I honestly can say don't post on the internet at all, are those that are dead, so what I've seen doesn't mean a lot, you know?
- 'Doc

I will tell you how I have learned what little I know. I don't have anyone around here to hold my hand and teach me RF theory while I am looking at particular devices. So, when you are green, not only do you not know how something works, you don't even know what questions to ask to figure out how it works.

So, I use these guys to help me formulate the pertinent questions....

Peakaboo, Pain, freecell(228), Ken White, W5LZ, Beetle, QRN, AB7IF, and nomadradio


And these guys to give me the answers....

Walter Maxwell, L. B. Cebik, Norm Dye, Helge Granberg, and Lou Franklin


Thank you all for your help!

Mopar

 

[noyb72]

mopar, I apologize, you did say books and not the net. I also did not mean to offend anyone, at all.

Sorry for the frustration

Ron.

 

[Captain Kilowatt]

I think part least part of the 'problem' is a definition of terms, another part is how those terms are used in a particular instance. For instance. The term 'on' or 'off' isn't an either or thingy, it's also a matter of degree. Except in 'special' circumstances like a class 'D' amplifier. That thing is either on or off, nothing in between. (Great for a 'pulsing' type signal such as CW, absolutely worthless for voice cuz it can't be "modulated" at all.)

I too suspect there may be a confusion in definitions of terms.

One thing Doc,and maybe I misread.My eyeballs are seeing things that aren't really there today after being up for the last 26 hours.Man I gotta sleep after that last 12 hour nightshift I keep telling myself. Anyway you say "For instance. The term 'on' or 'off' isn't an either or thingy, it's also a matter of degree. Except in 'special' circumstances like a class 'D' amplifier. That thing is either on or off, nothing in between. (Great for a 'pulsing' type signal such as CW, absolutely worthless for voice cuz it can't be "modulated" at all.)". Not true I say. An RF carrier can be amplified using any class of amp including class D or E or higher .The resulting RF can be modulated like any other. I ran a Nautel broadcast TX which operated the finals in class D and there are a lot of hams now building class E rigs for AM mode.

 

[mopar2ya]

Noyb72,

It is interesting to me how what you wrote infuriated me so much. I was definitely angrier than I have ever been about anything in one of these forums. I have found another weakness in my personality to add to the multitude of other weaknesses.

What you wrote:
“I understand you have taught yourself mostly on the net, do me a favor and google modulation.”

What you probably meant (I am being presumptuous here.):
“You seem to be adept at using the internet. Please look up modulation and see if it jives with your understanding of the term because you and I don’t quite see eye to eye on this matter. Maybe it is a simple terminology befuddlement. ”

What I saw:
“Hey goofball, you clearly don’t understand the term modulation. Maybe you should pick up a textbook occasionally. But, even a complete moron can use the internet. Here, let me help you. Google “modulation” and school yourself again, because you obviously didn’t get it the first time you read it.”

You know, if someone comes right out and calls me stupid, it doesn't bother me in the least. It has happened before. What bothered me was what I thought was a flippant insinuation of stupidity that didn’t deserve your highly educated attention.

I know from your last post that I was wrong about your intentions with that comment.
I accept your apology and hope that you accept mine as well.

I also have one other apology. Sorry lords! Maybe you will have to change the topic to “Watch Mopar have a meltdown for no apparent reason.”

Take care,

Mopar

 

[W5LZ]

QRN,
Ah, but then that 'D' class amplifier isn't the final stage, a modulation stage follows it, right? 'High level' modulation as opposed to 'low level' modulation. Not at all bad unless you don't happen to have a very high output modulation stage (not common at all in private as opposed to commercial radios stations).
I may be misremembering the class 'D' and 'E' thingys, been quite a while. If I remember correctly the 'D' or 'E'(?) class thingy became 'noticeable' sometime in the early '80s? (I ain't really that old! I just got a bad case of 'C.R.S'. Figure it's from RF exposure, all that beer, and them wild women.)
- 'Doc

 

[Captain Kilowatt]

Actually the class D TX used Pulse Width Modulation as do most higher class amps. I never did get PWM all figured out very well. The TXer's I had that used it never broke down!

 

[loosecannon]

mopar, just so you dont feel alone in this one; i thought the same thing that you did about what noyb wrote.
i thought, "how rude. mopar is a very helpful guy."

glad to know it was just a misunderstanding, as these things can easily escalate for no reason.

noyb, its neat to get a different perspective on the electronics we use for our radios.
i have found your posts quite interesting.

i can tell you of a book that will open up this whole radio world for you.
it is written specifically for people who already have an electronics background, but need to apply it to the CB service.

it is very well written and easy to understand. (well, it would be for someone who already knows the basics of this stuff.LOL)

its called, "Understanding and Repairing CB radios for the Professional Technician"
and its written by Lou Franklin.
you can find them on ebay, or by going to his site, which is:
www.cbcintl.com

you will LOVE this book. get it, and you will be posting here in two weeks about how much this book has increased your understanding of this application of electronics.

best of luck,
loosecannon