Introduction to Single Side Band
Vložit
- čas přidán 16. 05. 2019
- Introduction to Single-Sideband
TVI 30-611 Air Training Command Introduction to Single-Sideband. The video covers basic information about single-sideband and some of the history back in the late 50s early 60s. Regardless, if it is an old film it still covers the basic information about single-sideband and does so in an educational setting. The video is used in the RF Transmission course at Keesler Air force Base, Biloxi MS and is from the AETC video department. RF Transmission has permission to use this video for education purposes. For more RF Transmission videos I recommend to go to the RF Transmissions CZcams Channel to see what we are using in the classroom.
RF Transmission CZcams Channel / @rftransmissions225
Produced with CyberLink PowerDirector 16 - Hry
How are these old explanation videos so good? We need to keep explaining things this clearly!
Agreed, there’s one about how a differential works in a car. It’s an amazing and understandable explanation and demonstration.
My understanding was always just below the surface on how those side bands arose. Now I get it though - you can't modulate an amplitude (what AM does, obvs) without affecting the frequency of the carrier. Any increase or decrease of a perfect sine wave will momentarily introduce a distortion in that wave. Since that happens continuously, these distortions become the side band. I just never thought it through all the way.
They were made by smart and competent people, therefore they have high information density.
@@txorimorea3869 But not overly dense. It strikes a good pedagogical balance.
Because there are no jump cuts. Instead of ramming information through to keep you hooked, it is actually teaching, with a human flow that you can absorb.
I love the old military training films
They were very clear and concise.
US military instructional technique, as my former manager explained it to me: #1 First you tell them what you are going to tell them. #2 Then you tell them. #3 Finally you tell them what you just told them.
Yep along with drill, show them, and a whole bunch more
The only way it is "military instructional technique" is because literally all schools use at least three repetitions, it's been bog standard teaching for over 100 years. But sure, let's assign some magical qualities to spending eight hours in a single classroom studying a single subject.
The military can spit out a radar-fixing robot faster than you can Keesler Air Force Base.
Colleges take foure years, but at the end you get a SOCIALLY FUNCTIONAL HUMAN BEING who can fix radar.
Big difference. A crucial but never discussed aspect of force retention is the simple fact that most military jobs can't be translated to civilian jobs. Loading luggage is not the same as being a bomb loader. The military provides daily structure as a parent would, as a result, we don't learn how to provide structure for ourselves until after we get out, at which time it may be too late to learn that stuff. If you haven't learned decent social skills by the time you're thirty, you never will.
@@railgapI don't think today's colleges are turning out many socially successful people. Socialistic, perhaps, but not very successful, given their learned needs for personal pronouns and safe spaces.
Best explanation I've ever encountered. Seems like few can be this clear and concise nowadays.
Concise has been replaced for clicks.
Spend a lot of time in tech school classrooms these days do you? Been taking a lot of courses and struggling? Or are you just talking out of your ass because you're old and the world confuses you because you refused to leave your comfort zone and so you couldn't keep up. You probably think there's no good music available today. People like you give people my age a bad name. Sit down and keep quiet until you have something intelligent to say.
I took BEE (Basic Electricity and Electronics) classes in the Navy in the late 80s. We still saw a lot of these old films, and some of the technical manuals were pretty ancient as well. Electronics doesn't really change though, so what was applicable then is just as applicable now.
This film is ancient, but it's absolutely THE best explanation of SSB I've ever heard! I like how he drives home the point of phase-shift appearing as amplitude-shift and vice versa.
Love these only training films, they are usually so straight forward and no nonsense.
yeah the modern youtuber really is grating compared to this. all shoving their face in the screen and hyperactive. this is soothing and i can read it in the shed with a cup of tea.
Excellent. I especially loved the explanation of why we see an enveloped carrier in the time domain (due to addition if the side-band), but in reality the carrier is continuous.
If only training programs we have now could be this clear and useful.
I agree! I had watch this film back in 87 going thru Ground Radio maintenance in the AF. It was made in the 60s and when I came back to Keesler in 97 as an instructor it was not changed. I ordered a new training update on just today's technology (film) but the same outlay in format of info. Retired and do not know if one will ever be made
Would have been great to see this before my Ham test. I would have actually understood what the question was instead of memorizing the answers and not knowing crap.
@@dougtaylor7724I get what you are saying. It was not until I got to be an instructor when most of the electronics I dealt with became clear.
@@johnmayer4747 yes, the best way to truly learn something is to teach it.
Dang this helped tremendously! Just started getting into amateur radio. Thanks for posting this!!!
You are welcome!!
Great video. Thanks much. Cheers
Dude thank you so much for uploading this. Cleared so many things up for me!
Now, I understand SSB. A B/W video could explain me better than my text books.
That is because the use of Single Sideband technology became new in the 1950's.
my right ear loved this
Very clever to have a talk on SSB on just the one audio channel :)
Something useful from Xiaomi here. MIUI has video toolbox, when you go to audio, set volume to 1, it boosts the left channel to approximately match right channel.
I thought my left ear phone died. They did this on purpose?
My right ear enjoyed this video.
"A SSB Receiver is much more difficult to tune than an AM Receiver." Very true.
Traditional television is a good example of compromise: carrier with one sideband suppressed. The waveform matches with some savings in power and spectral availability.
Excellent explaination.
Thank you very much for the video. Excellent :)
this was awesome. and i love how the audio in this is only on one channel. poetry.
Gosh, what a perfectly designed presentation! I wish I'd seen that when I was studying for my radio amateur exam (when I was at school, many thousands of moons ago). 🙂 🙂
The carrier in AM signals does convey information....it tells the receiver where the sidebands are relative to the carrier.
Since the carrier is missing in SSB, the radio operator has to tune the signal manually by listening to the audio and adjusting the beat frequency until the audio sounds right.
Channelling the intro for the original (1960s) Outer Limits.
Super. Thanks for sharing!
You are most welcome!!
Excellent ... Thank you ...
Back in the suit and tie day.
I thought fran labs was the only one archiving these classics
Amazing
Now I understand, thanks
These are some serious fundamentals lol, what a fascinating behind the scenes look at it all!! I love it 🙏🏼 I wanna know more now lol, what are standard audio circuits?
Depends on what radio you are dealing with. Most regular AM/HF radios for communication are between 300 hz to 3Khz. If you are dealing with FM a standard Audio ckt is 20 hz to 20Khz. Those are generalities. They get more complicated with technology as this info was back in the 50 thru 80s. Now they are putting data and voice on the same ckt without any detectable degradation
2:47 - anyone else ever have these acid hits before? super great lsd! 'control tower sheets'... loved em!
I love old military training videos, but this one seems somehow unique. First, it features that jaunty jazz music intro, I've never heard another one of these with jazz. Second, it looks as though it was produced on a magnetic tape media instead of the usual film.
Where can I get more of this types of quality videos? I love it.
This is an old Keesler AFB training film for ground radio maintenance when I went thru back in 87/88 (active Duty AF). Came back in 97 as an instructor and it was still there till I retired in 2003. Came back as a civilian instructor. After many changes in the career field, was able to keep it going in the RF theory module I was in charge of before retiring as a civilian. Made an RF Transmission CZcams channel for several blocks where the theory for RF module resides. You will see the updated info the military teaches. Not classified or FOUO. www.youtube.com/@rftransmissions225
So what have been the greatest advances in radio communication?
Some candidates might be:
1. Spark gap code transmissions that first allowed practical radio communication
"CQD CQD CQD This is RMS Titanic, we are sinking SOS SOS SOS"
(The most famous signal ever sent by spark gap transmission?)
2. Continuous wave (CW) code transmissions allowing high quality radio signals. This relied upon the development of vacuum tubes
3. AM radio transmission, utilizing vacuum tubes for generating CW signals and amplifying audio for modulation. This allowed mass media radio to develop.
4. Frequency modulation
5. Development of RADAR and cavity magnetrons (1940s)
6. Development of transistors (1950s)
7. VHF, UHF and ever higher radio frequency utilization 1950s
8. Development of practical mass media television 1950s
9 Development of Single sideband radio transmitters 1950s
10 Development of integrated circuits 1960s
11. Digital modulation of radio signals 1970s
Looks like the 1950s were the peak decade of radio frequency developments
The decades since the 1970s looks like immense improvements in the technologies of integrated circuits and digital modulation of radio signals.
But this is off the top of my head. What do you think?
25:10 - "So, conventional AM will be with us for quite some time in many applications".
Uh, *when* was this film made? :)
If I remember correctly it was made back in late 60s early 70s.
PLEASE redo this video with audio ON BOTH CHANNELS !!
Great video. Was this originally on an 8mm film?
Not sure. Was completed on Keesler AFB back in the 60s
Quite interesting how back then the words "information" and "intelligence" were used as synonyms.
Hence CIA: Central Intelligence Agency. Military and the like still likes to use 'intel' rather than 'info'.
It was how well information was received not either or.
Where would the BAL MIX get its reference frequencie?
Although much is well done and an excellent narrator has been used, an error in the manuscript for the explanation of the block diagram devalues the quality of the film production from 04:10 onwards. The high frequency circuits after the modulator/mixer do not have a low impedance for audio frequencies, but a very high one.
Makes even better that this heard on right side speaker (youtube mono?).
Why not transmit the carrier, but at greatly reduced volume, which then can be used to provide constant synchronization of the BFO? The stereo multiplexing of the broadcast FM uses the 19 kz pilot tone to reconstitute the 38kz frequency of the stereo difference frequencies. The NTSC color television system uses a carrier burst on the back porch of the synchronizing signal to reinsert the carrier frequency for the color differnce information.
Carrier and one of the sidebands carrying the audio is not in the output as it was meant to transmit the the audio portion at a greater output since everything was suppressed. HF was before TV and FM was in the mix during this time frame. Frequency range of HF was using the ionosphere at great distances compared to the high frequencies. You have to remember when things are invented, thinking ahead is not in the mix.
I do have to add this is old technology compared to how things are now. We do not know for certain whey they did what they did during that timeframe.
Why do the frequencies get added? Isn’t that frequency modulation/manipulation?
I thought I was pretty sharp on signal modulation. I love the vintage military training videos, and this one gets closest to grasping the sidebands. Have not found one single explanation of why changing the amplitude magically generates Fc+Fa and Fc-Fa. Other than “here are the sidebands, because they are always there.” Frustrating.
Can someone please explain what he says at 4:06?: "The audio frequency is not developed in the output because the RF resonant circuits have a very low impedance to audio." I know that the audio is not carried through, but just the carrier and the USB and LSB. But I'm trying to understand the relationship specifically to how a low impedance to audio is the reason? Is there some way I to visualize this? Impedance is the opposition to alternating current. It's just not sinking in.
A URC119 HF Pacer Bounce military radio is the best example I can give you. There is a maintenance procedure to vary the impedance of the mixer circuit where only Side bands go thru and nothing else. It acts like a filter but it is purely resistive, balancing the impedance of the circuit. If you get the impedance wrong, only the audio goes thru, get it right, the lower and upper side band frequencies go thru (the double balanced mixer eliminated the carrier). Think of this of a frequency sensitive circuit, you could see this on a spectrum analyzer. I am going off of memory as I used to work and teach this radio to the military students (30+ years). I cannot find my schematics but will keep looking. Hope this helps.
I work in digital TV and I just explain it simply as junk ……… to signal as my spectrum analyser shows me ……===…===…=== is 3x tv channels.
It's a fancy way of saying that the RF filter is practically a short for audio signal. It's not incorrect, but different from the way we are used to think about it.
Have you ever looked at an RF circuit board? That's not a sarcastic question, if you've never seen one you should look at some videos by "The Signal Path" or look up a picture of a "butterfly stub filter". If you look at those pictures it should be obvious that those circuits are short circuits to frequencies near DC.
It means that the resonant circuits allow frequencies below RF to pass to ground, so they’re not present in the output of that stage. Resonant circuits are essentially filters where signals at the frequencies you want see the lowest resistance path as the path to the output and the other frequencies see their lowest resistance path as the path to ground. Impedance is just frequency dependent resistance. The confusing bit is that “low impedance” here means low resistance to ground, but you can think of that as “low resistance to gone”.
Next video, can you explain mono to only one ear?
Old training film and had right channel only. Sorry. I can take the audio and duplicate it on the left side and it is on my to do list.
The "Big Frequency Oscillator" reminds me of SpaceX's "Big Falcon Rocket" 😏
I wish some of the youtube ham guys would watch this as they really dont know much, they just regurgitate what they heard and think they are explaining things but they dont know anything
Aw3som3!
It's a shame they missed some pretty obvious illustrations during the production of this film. SSB-received-as-AM would have been helpful, as would SSB-received-with-BFO-slightly-off. Even the o-scope version of the narrator "over single sideband" shows some carrier and omits mistuning distortion.
It doesn’t explain how single sideband captures all the information. The most difficult part is brushed over. If I put a rectifier on a signal it kills the other side of the bandwidth.🤔
94.3% sure this is the same guy that did the turbo encabulator vids
Nice to see I am confused by some 1950s level tech 😂😭😂😭😂😭😂😭😳😳😳
❤GREAT CHANNEL❤
Is "intelligence" used to mean what we would today just call "information"?
Yep, voice or ins some cases data, it was back before military intelligence became an oxy moron..... lol BTW, data could be as simple as Morse code
"Intelligence" in this context is how well you can pick up the signal.
What kind of AM radio band(s) are in use now?
It’s still in use pretty much everywhere, particularly from 75Mhz down to 0. Shortwave broadcast is mostly AM. Amateurs use AM. Low frequency stuff is AM. Aircraft use AM. There’s the middle wave and long wave broadcast bands that are all AM. Citizens Band is still AM.
@@rabbit6872 I meant in pertaining to this video. Are AM radio stations using side band or wasting energy always broadcasting the carrier wave?
@@lightdark00 AM broadcast uses both side bands. Some fancy implementations actually transmit stereo with one channel in each sideband but it’s not very common and requires a special receiver. These days they roll off the lows and highs to reduce bandwidth and put more power into the intelligible speech bands which is why it sounds kinda crappy. AM used to be pretty high fidelity (but with radio noise) - it’s mostly just talking now though.
For this type of explanation format, this is quite good, but I see this a bit differently. It's a typical, instinctive response to be scared off by equations. But when a subject is deeply technical enough, you really need some equations to accompany the verbal content and pictures. This presentation, though it's good enough as far as it goes, can't really take you all the way to a full understanding of this subject.
This video was made to keep it simple for the new recruits at Keesler AFB. Normally the lecture provided more detail info. I remember we would go thru the schematics of the URC119 and review each step of the making of the waveform to the output. It was eye opening. As far as equations, the recruits were not at that level..... yet. That would be a few years later and more training.
Analoge versus digital demo..I prefer the analoge instruction..
Agreed!!! Analog seems so much more like you are there compared to the crisp clear AI sounds.
I can just imagine an old trucker saying “Boy dat things got some swing”!
And they did this without ever using audio from an actual SSB or regular AM signal. Perhaps the exact opposite of how it would be done today.
It is my understanding the Spectrum Analyzer was not in wide use and the military (provider to the tech info) did not have one to demonstrate with. It is my experience in military training at Keesler, we never had the money to purchase new updated equipment but had to make do with what we had.
Good explanation. A training video today would be 90% incomprehensible math, Fourier Transforms, etc.!
If only! I see so many purported training films that contain very little information and doesn't even bother with the actual signal math, with or without Fourier transforms (fast or regular). This old film showed both the time domain and frequency domain perspective and explained how the bandwidth reduction was done on the transmitter IF signal by using sharp highpass or lowpass filters tuned to cut right at the IF carrier frequency, thus being independent of the assigned carrier.
The BFO detection method was less clearly explained as it only explained it for the case of a zero intelligence 1kHz test tone and not a varying frequency message .
Some time indeed, I think last big AM station's has shutdown in Britain this year, Finland shut last at 1992 and some countries still uses it. When analog AM some day dies totally, frequencies go use in digital signals. Maybe IoT or something electric meters signal to grid and water meters off-site reading. Now those uses already 450MHz I think. But as he said, there's never enough room on bandwidths spectrum. Digital signals helped little bit that too.
The NTIA along with the FCC are trying to divide the frequency spectrum even more with narrowbanding. Some parts of the spectrum has already seen the 25Khz divided into 12.5Khz a few even to 6.125Khz. Newer technology is the driving force to it.
Biggest problem is that the mobile phone industry is hoarding every available frequency, enticing governments with huge auction prices funded entirely with borrowed money.
ante geia!!!("en katalabainei").
What language was that?, CZcams cannot detect and translate such short messages,
@@johndododoe1411 "greeklish" ;)
Licensed ham and I still don't know what the hell I'm looking at. Man, they'll let anyone get a ticket these days
You mean like you. This should all have been on your licensing exam when you got licensed to build this equipment and correctly manage its frequency use .
@@johndododoe1411 lmao, takes a certain kind of dodo to completely miss the joke they just read, and then proceed to spout off about things they clearly know nothing or little about. Never change, Johnny boy
Nope... Still don't understand... Can anyone explain to me what the heck is a sideband? I understand AM and FM. But where does "sideband" fit into this.
If you understand AM, you have an upper side band (USB), a Carrier, and a Lower Side band (LSB). The carrier "carries" the intelligence (voice/data) and the intelligence is in both USB and LSB. The carrier is a placeholder. In HF, the carrier is suppressed and the one of the side bands are eliminated. All the power is in the one side band. For FM, all the intelligence is in the carrier but covers a wide range of frequencies in the carrier. For simplicity, there is no side bands in FM. Hope this helps.
@@johnmayer4747 Thanks! I think I'm closer to understanding what a sideband is now.
So its a definition problem. Rewatched the video with new understanding and many parts made sense now.
But I still don't get how a sideband is generated or how it looks. (hey, atleast I know where it is now!)
Like, how does a sideband transmit at all when the carrier is gone?
(in my head, the carrier is the one carrying the information, if the carrier is gone. What is carrying the sideband?) (I know this definition of carrier wave isn't right, but this is my limit as of now)
@@kenco2600 I am not sure if I can create a picture using words but will try. For simplicity we are going to try an am transmitted voice signal at 100 Mhz that has 25Khz bandpass in the frequency spectrum. Looking at a spectrum analyzer, you key the radio (transmit or push the mic key) the carrier will be at 100 Mhz. Since you have no voice added yet there are no sidebands. When talking, typical voice is between 300 hz to 3khz. You key and talk, you will see the carrier at 100Mhz and your voice will be on both the USB and LSB. Let's go further since it is really hard to see all the voice frequencies at one time. If we take a constant 1 Khz audio signal and apply it to the mic, on the spec analyzer we should see a LSB, carrier and USB signal. We can even apply where those signals are in the frequency spectrum. The LSB is calculated 100 Mhz minus the 1 Khz and should be 299.999 Mhz. The Carrier will be 100 Mhz, the USB should be 100.001 MHz. All of those points are measurable on the spectrum analyzer. With voice from 300 hz to 3khz it would be 299.9997 Mhz to 299.997 Mhz on the lower sideband, carrier at 100 Mhz. The Upper sideband would be 100.0003 Mhz and 100.003 Mhz. If you are still having issues with understanding, we can set up a time and place (discord) so you can ask question and I, can hopefully explain it to where you understand it.
@@johnmayer4747 uhhh, this is a lot more complicated than I thought. I didn't understand atleast half of it but I will try to understand it.
Still, thanks for the answer!
@@kenco2600 its ok, it took me a few months of going over it before I finally "got it". if you need help, just give me a yell.
If you don't thoroughly understand something you cannot thoroughly explain it. These guys knew their shit nowadays people just Google everything, therefore half the time teachers don't even know what they're teaching they just Googled it the day before
We had to know it down to the transistors, caps, resistors, ect to teach back before everything went to card remove and replace. So sad the newer gen does not know how a circuit works in order to convey what happens next. Thinking if you want to know engineering today, this may be true.
No multi-color neon backlights and no “let’s get right into it” after the 7 min mark?? Must not be good info.
Audio ist just on one side.
I hear no audio. Ron W4BIN
So went to video to check it out for no audio. Try listening to it in mono as if you are listening it in stereo, it is right side only. Will have to use Audacity to load it as both left and right sides it might be a while before I can get to it..
LOL - 3 GHz - und heute nutzen wir bänder bis 6 GHz für kürzest-strecken-funk…
and you don't want to stand too close to that antenna when you transmit....you can fry your eggs.
Depending on the output wattage. 10 watts, eh... whatever, 1kw, caution, 10kw, do not get close. Worked on 10Kw and it was often you needed to turn it off before getting close to the antenna. 1Kw, you can get close but do not touch the bare antenna wire. Just to give you an idea touching bare antenna wire is hazardous, touched a 5 watt radio antenna wire by accident and got a quarter size 3rd degree RF burn. A lot of colorful metaphors was said. Took a couple of weeks to heal. As far as RF radiation concerns just play it safe.
@@johnmayer4747 the antenna's I work around are about 100 watts output. Anything that makes you tooth fillings warm is bad.
"Sideband" (as in single sideband) is one word, not two.
left channel has no sound
I have full stereo. A little scratchy, but both sides are working.
My fear is the government will do away with the AM broadcast band for 2 reasons...
1 - So they can realicate the frequencies.
2 - To silence talk radio and thereby allow the government to more effectively control the narratives and attitudes of the people.
The free and open sharing of ideas is dangerous to a totalitarian government.
Isn't it interesting that automotive manufacturers just announced that they will not be putting am radios in their cars going forward?
What makes you think that the narratives you get from talk radio represent anyone besides their sponsors?
What exactly would the AM broadcast frequencies be reallocated to? The big need for spectrum is for cellphones and digital data, which simply won't work on the very low frequencies of the AM broadcast band. The automakers are getting rid of AM in ELECTRIC vehicles, because of RFI issues with the motor drive electronics wiping out AM reception. But fans of right-wing AM talk radio aren't likely to buy an electric vehicle anyway....
@@bobweiss8682 Even if they buy one, they still can use a web sdr service and continue listening at the HF bands
@@thomasking5970 : Sure sponsors are a big deal, but the hosts can't totally blow smoke or the people will quit listening and the sponsors go away.
Also, being able to call in an express your opinion is very valuable and is harder for the advertisers to control.
I prefer more viewpoint and forums than less.
Sorry. Too technical for me I never finished high school my iq is 79,
this was 1 of many dozens of videos in the military electronics training series. not a stand alone video. If you saw the training series from the first episode then this would have made much more sense.
That map looks like someone's kid drew it.
What did you expect from military training from the 50/60s? They were lucky to have video back then.
@@johnmayer4747 I expected higher quality, like the highway safety video, Mechanized Death.
@@wesKEVQJ This was a locally made video at Keesler AFB with a limited budget. Back then the local military did not have the means to produce a quality product, just one with the information in it.
@@johnmayer4747 I know, I was just making fun of the map, I was in the Navy and had to watch countless safety videos. Most of them they showed me were from the 60's and 70's though. Are you saying someone's kid drew the map?
@@wesKEVQJ Sorry, thinking you were a troll and was defending what they had back then. Retired AF and taught Military my last few years in and then taught them as a civilian, now retired. The quality of videos the local AV training has improved significantly. I made a CZcams Channel RF Transmission for the RF Transmission flight b4 I left and they are still using it today. Has some decent videos you might be interested in.
these old videos might look better when passed through an AI upscaler
the scanner or file compression did a number on this video. the original was almost certainly an order of magnitude higher in definition
@@manitoba-op4jxFortunately the resulting low resolution video is still quite sufficient for the information .
Bukkddht
You should 😢❤ pop pop p pop 🥤 pby bypass up
Very bad video quality. I didn't think that in 2020, video quality would actually be the limiting factor of the overall quality of a 1930s recording.
Sound only from the right channel.
You need to go back to 1950`s and stay their.
In the 1950's schools taught the difference between there, their, and they're.
@@dougearnest7590 Even post 1950's the differences were taughted.
@@Look_What_You_Did - I know that, but I have serious reservations about what they're teaching nowadays. The posts I see online (CZcams, Facebook, etc) it looks like almost everyone under 40 is getting it wrong 100% of the time. (You'd think the law of averages might come into play and we'd see them get it right about a third of the time just from guessing, but no such luck.) Obviously, they have no idea of what the apostrophe is for.
@@dougearnest7590 It had to be dumbed down, so the 56 IQ morons would not look like the 56 IQ idiots that they are. Then they were bussed around to spread their stupidity.