37 years trying to understand the superheterodyne receiver I finally have a decent picture in my mind! Tank you so much for taking the time to film this video!!
Thank you. I might also show you this video (ruclips.net/video/Vf06HSR4LdY/видео.html) which illustrates and demonstrates how a superheterodyne receiver works.
I am grateful that someone took the time to document the class and post it given the resources they had at the time to do it with. Granted, the audio could have been better but I, for one, am grateful. Hands down this one video clarified the lack of understanding that I had with Ocilliscopes and audio signals. PS, If you could redo the whole video from the beginning and have multiple, switched cameras, a properly EQ'd boom mic, picture in picture with clean transistions and ask everyone to remain silent till the end of the presentation. That would be great. 😉 Thank you Allan.
This is one hell of a course in Oscilloscope. I've been looking and watching "how to, use oscilloscope" videos for several years now this is by far the best one I have seen. Thank you very very much I'm going to save this and watch it again with the scope by my side, definitely more than once.
I've now seen an excellent electronic training course taught at Princeton for FREE! Likely with more knowledge than most professors! THANK YOU! I only wish I had even half this info in radio club meetings I've been to in the past. Most clubs you're lucky to get past "beginner" electronics training!
I heard all that stuff, but I didn't listen to it......lock onto the instruction.......no complaints.....good video.....good enough to be worthwhile.....thanks, fm
Greetings, Alan! To my knowledge, I've viewed all of your videos, and I must say, you are perhaps the finest educator I have ever seen, either on-line or in person! Your ability to clarify the most intricate electronics concepts has had a tremendous impact on my understanding of the topic, and I'm certain I'm just one of countless many you have enlightened! Thank you so much for all of your efforts in sharing your vast knowledge of electronics with others! Well done, Sir!!
Now that you mention it, I was hoping you could shed some light on the topic of parametric equalization. While I understand the basic concept, the specifics of how and why they are designed still eludes me somewhat; for instance, are there parametric eq's which incorporate shelving? Also, is it only frequency that can be adjusted in voltage-controlled filters, or is it possible to modify bandwidth or emphasis as well?
There are a couple of good topic ideas here. Suffice it to say that it is possible to design voltage control filters that include full parametric control (BW, Q, F). It is also possible to design voltage control shelving filters. I don't know what is commonly used in the pro-audio field - although I suspect that it is nearly all done in DSP these days...
I had no issue with the background noise. I've been to enough club meetings to expect these sorts of things. More importantly, this video has taught me more about truly using my scope than any other source up to this point. Thank you for that! Nice work. 73
@@unlokia Microphone NOT close enough to Alan's mouth Result: we hear the sound from wall bounce... and direct from source... and reverb delay... makes for a cloudy image... difficult to decipher. Multipath distortion. Better would be a closer mic This is important\t material We need to hear it clearly Love W2AEW
0:36 "Scopes For Dopes" 😆!!! I need to check that one out myself! I greatly value your videos. All of them are tremendously informative and illustrated with the formulas pertinent to understanding the concepts. Thank-you! God Bless
I see other comments about their equipment. I have many oscilloscopes. I have a Tektronics 453 I bought on E-Bay. It works... Perfectly as far as I can tell! It just smiles at me everytime I see it. And I smile right back. Great instrument!
I picked up a Tektronix 468 for $50. a couple of years ago. Wish I had seen this video when I was trying to figure out how it works... Think I still need to watch this video a few hundred times.... Thanks for sharing!
I do wish the guy that is trying to act like he knows all the answers with his non-stop "right", "Yeah" and "Exactly comments would have keep quite. Even when Alan would have a slip of the tongue the fellow would change his answer like Alan did, Alan would say "no that would cause the signal to go up. the guy would say "you're right it would go up". Alan would catch himself and say "My mistake it should have been gone down." The guy then says "You're right it would have gone down." Please be still at the next session so we can hear the speaker.
This was great. I grew up in Hunterdon Cty and was originally licensed there in '57. I have been watching your VNA articles but recently picked up an HP 1740 scope (You should watch Dave's EEVBLOG on fixing one of these!). Of course I also have a fondness for tube gear and still have my Halli S38e, which is of course an All American Five. It seems to work all right but now I can fearlessly apply my HP probes to it (IF isolated). BTW I just ordered an Owon HDS272s to eliminate those ground issues. 73, Barry VE7VIE and WV2J ex WV2ECZ
It must be the ham in me, but I just added a band pass filter in my brain. Didn't notice the radio or other noises at all, what did annoy me was the grunts and comments from the audience. Nice job as usual Alan, imparting your vast amount of knowledge to the less fortunate 😄 Cheers. Alan, GI0OTC
Just watching this excellent presentation even though I only have few idea of what he is talking about but just love listening to this intelligent presentation, thus the background noise and the distracting hhmm really meant nothing if anyone really wanted to listen to the concept and idea he is passing across. Good job.
Very informative, but hard to stay with Alan because of 1) background noise / music and 2) fellow in the audience who needs to be heard every 30 seconds or so . . . "yeah" "oh" "hmmm" etc. Feels like they kept forgetting it was being recorded.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
@@w2aew was a radio station? I thought it was a little transmitter of very old music from before the great war being played from a cellphone to a transmitter because there were no commercials, and no station like that i'm aware of out there. Anyway, it added a great ghost movie theme background and the guy right next to the camera was probably the main ghost :) I heard that they invented a "nagging" filter just to eliminate the funny sounds he made and give him his calories back
Just watched your video and have to say it was the finest well spoken video I have seen in a long time. Great job I have a NOS Sencore SC61 and after seeing your video I feel confident on using it now!! I also subscribed so looking forward to seeing more!
Thank you very much for a great lecture, exactly what Ive been looking for for ages! (OK the radio noise is a little annoying, but I could "tune it out" ok). Thank you!
To all the complaints about background noise, talking, poor microphone placement, etc.. This was a presentation given by a guest speaker at a monthly meeting of the NJ Antique Radio Club. Not a professional lecture in a studio. Lecture halls are not the best environment for recording. Few clubs are lucky enough to hear a lecture by such a learned individual.
I bought a portable oscilloscope, I guess I won't be able to use it on my Admiral A31 radio for testing, since it's not to Ground ;-) Tks, great course ! I manage to fix it replacing all capacitors(keeping shell for antique reference), fixing AC wiring, all lamps were ok, I bought a second set of lamps for the future at a low price on e-bay....
Outstanding video on Scopes. Best I ever saw/heard. Thanks a ton for the effort and the information. Too bad your audio-visual guy had a radio program going next to the microphone thruout the entire presentation causing a somewhat distracting influence - which seemed to get louder as the presentation progressed.
I kept pausing the video and turning down the speakers until I finally realized it was something in the video causing the background noise. Unfortunately I could only make it though the 8min mark. It was distracting to the point I kept stopping and rewinding because I was losing track of what Alan was saying. It was almost disorienting. Sounded like singing then talking then like an old TV show. Unfortunate because I guarantee that presentation was excellent. Everyone who was able to partake in it was lucky.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
I more than enjoyed the video Alan !! I learned a lot !! Your communication approach is excellent - perfectly pace; with highly focused content; and effectively sequenced for optimal assimilation. I really wish I had this video rather than my Electrical Engineering O'scope classes in college !! Thanks for all your postings !!
Your presentation was extremely well done. I would greatly appreciate your help with one question: how do you know where to connect the ground lead of the probe to be safe? Do you analyze the circuit and identify ground, do you just use a good known ground in your home/office,...? From the end of the video where the radio is visible it looks like you put the ground clamps on a horizontal wire -- how did you identify this as the correct spot? Thank you.
Great video. Thank you. So is the Radio under test and all the mains measurement equipment including the scope plugged into the isolation TX? Ground lead clipped to chassis of radio?
@@lampmanpaul7459 Usually in such cases the scope is on an isolating transformer, though the equipment itself could be on it instead, but if the equipment during testing connects to something else which is grounded, you might find out after you damage something. You can always connect a high impedance voltmeter and check for both AC and DC voltages between the scope's ground clip and the equipment's ground or zero point where you plan to attach scope's ground clip. You can also check if there is a current between (AC or DC) when connected via a sensitive ammeter and a resistor large enough (physically and resistively) to prevent a damaging current for such circuit (usually in miliamps). Sometimes there is some small current between grounds regardless, and you could play it safe by using either a mid-value resistor (100 to 10k ohms), or a capacitor between 10nF and 100nF, or a 1k ohm resistor with a 100nF capacitor in series which provides DC/galvanic isolation and surge protection (through the cap). Be careful and creative.
Very friendly presentation that even I understood :) Many thanks for the clear presentation of the basics of measurement oscilloscope I greet and as always look forward to the next interesting video.
I've been trying to learn on my own how to use scopes. I restore vintage tube receivers (Fisher especially) and a major realization I came away with watching this video is that I don't know WHERE in circuitry to probe so I can get usable images on the scope. This video helped. I sure would like to know where else can I go to learn more about where to probe.
Thank you for your very interesting lessons Alan, they are great and i personally learned a lot. Just one little suggestion if i may... it would be very helpful for non-native English speakers like myself if you could use a microphone near your mouth to record the audio because the echo from the room, the noises from the radio, the random noises in the room, etc make it harder for us to understand your words (English subtitles would be even better but i guess it takes a lot of work). [This is not usually a problem in your "normal" videos] Again, thank you!
Fabuluous course ! I grew up building tube superhets with multimeters, rf/af signal tracers, rf/af signal generators, and yes even a wobbulator, but I never had a scope to see these waveforms visually ! Now that I have a good scope, you have inspired me to build a tube superhet again ! Thank you for giving me the joy of doing that ! One question though, in the output stage why dont we hear the ripple in addition to the AF signal ? You said it is rejected as a common mode signal, but I dont see how the single ended tube output stage does that. Can anyone clarify ?
The ripple appears on both sides of the primary of the output transformer. The only thing that couples across the transformer is the AC *between* the primary inputs. The ripple doesn't cause the voltage across the primary winding to change, so it doesn't couple to the secondary.
Excellent video Alan. I have modern digital scopes but I still find myself using my old Tektronix or B&K analog scopes. Just can't beat the look of a warm glowing CRT. Keep up the good work. I recommend your videos often to newbies just getting into electronics. One minor suggestion. If you ever do another classroom type session with a radio keep the radios volume down until its needed. With the camera being closer to the radio its audio level was almost higher than you at some points. Just trying to help. :) Mike
Do you have a version without the radio / TV sounds in the backround? It makes it quite hard to focus on what you are saying, which is a pitty given the great presentation.
Outstanding lesson on a subject that is at the core of my main interest! As a 100% do-it-yourself'er...Due to all your videos, and AA5's, progress in this field has been at a slow/steady pleasing and enjoyable rate! Thanks for this video!
Alan, if you do any of these in the future suggest a wireless lapel mike--there is a lot of background noise and echo with the camera mike alone, and it's distracting...
But even given that, it was one of the best presentations I have ever seen on CRTs with or without the background noise. This is bookmarked in my notebook and I will also download a copy as its that outstanding.
A very nice presentation, I learned a lot, thank you. You could make a video about your first scope one day. I looked up some Allen B DuMont oscillographs through image search and they seem to be interesting devices. Perhaps a video explaining how to control one of these old scopes and comparing it to a more modern one.
Between the noise of the radio in the background and some one talking next to the camera the distractions ruin the video. Brilliant idea. Thank you for trying.
Alan, another wonderful and informitive video! I find myself revisiting your videos from time to time after I encounter something familiar and then, boom, your video (on whatever the topic) comes through with clean, clear and concise info to help me better understand whatever it is I'm thinking about. As a little request, could you maybe do a video that hits on the do's and don'ts (especially with regard to analog or CRT scopes) with regard to how power cycling, run time and etc may have a detrimental impact on those appiances? IOW, I may be wrong, but short cycling (using your scope to look at something for maybe 5 minutes) from what I understand is bad? Somethig about quick heating and cooling cycles? Is it better to just keep it on and keep the trace dim when not in use? Maybe just old wives-tales? Also, I have a couple of Tek 24XX series scopes. I believe they have volatile memory that uses a battery? Those have an infinite life? What are the caveats and possible reprecussions of a memory battery going dead? Any insight? Enough stuff for an informative video? Just spit-balling, but something like that from you would be awesome! At any rate, keep those vids coming! Great stuff!
Excellent presentation. For slide 18 can you explain a bit more about the use of an isolation transformer? I have a Tektronix Technical Brief 'Floating oscilloscope measurements and operators protection' (51W-10640-1) that calls this an 'unsafe and dangerous practice and should never be done!'. Have I got this mixed up? Y
It's better to use the isolation transformer on the radio, keep the scope grounded. Then, when you clip the scope ground lead to the chassis - it becomes ground potential and a lot safer to work on.
@@w2aew Thanks Alan, perhaps the subject of a dedicated video? Also could you consider doing something on the use of a scope and signal generator for assessing balun performance (not the transmission line)? Y
@@w2aew I agree. Grounding an oscilloscope and using an isolation transformer should be the subject of a dedicated video indeed. It's not as intuitive or as easy as one might think when first starting out in radio repair. We'd appreciate it Alan!
I Gave up watching some 10 mins into the Video, I just. couldn't put up with the Radio or whatever it was that was close to the microphone... It Ruined what could have been a excellent video.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
Thank you... I figured it was the radio and hoped some one would have pulled the speaker or put a dummy load on it with a switch. The fellow talking next to the camera mic was just as distracting. I had so hoped to follow this lesson... brilliant idea, Thank you
Usually I'd be the first to be bothered by "little" things like the radio or the guy talking, but I found the talk engaging enough that I didn't notice either very much, or when I did I didn't care. Which is incredibly rare for me. I really hope you guys give this video another chance, cuz it has some excellent content from an excellent presenter. I can totally relate, though. Something relatively small like that can be the difference between an amazing lecture or something that's completely unwatchable. Especially if you have ADD\ADHD as I have. Your brain just latches on to any little distraction and it becomes the entirety of your focus. It makes reading stuff damn near impossible for me, so channels like Alan's are truly a godsend.
Great video Alan! I’ve learned more electronics from you, Joe Smith and Paul Carlson and a few other you tubers and some good books than I did from any courses I ever had. I pretty much work on old guitar amps, audio gear and most recently tube radios. Lately I have been repairing my old test gear too. I have an old Tek 485 coming in today. That will be a challenge, but I think I’ve found the go to Tek expert on RUclips. 😎
Not familiar with Joe Smith. But Mr Carlson's Lab is a great channel. I loved his video on the tube op amp. I'm not big into RF or radio, but Alan's piqued my curiosity in them more than once. I can see being a lot more interested in them once I've learned more. EEVBlog and Big Clive were the two big ones for me when I first got into electronics a couple of years ago.
You work for Tektronix?! I knew it!! Something about your videos. Tektronix always has and always will kick HP/Agilent/Keysight's ass. ...and I also just bought my second solid ink printer, another Tek win. ... and my 7623 is still in active service...
Could you do a video about safe guarding your oscilloscope and spectrum analyzer when measuring voltages and signals with older tube type equipment. I think that the scope is easy enough but the spectrum analyzer has a low impedance of 50 Ohms. Thanks.
I agree with you Trent. Really nice presentation destroyed with background noise. Not sure what the purpose of it was, but I could deal better with the gentleman every 30 seconds or so, than the background cartoon audio.
What are the best (or your favorite) tektronix publications that you recommend for beginners, middle of the road, and advanced users? I still discover things in my 475 after all those years even though i have one of the most recent scopes. I will never understand why the first scope makers in history ( very probably tek) used the word "trigger" for what they used it for. The meaning of that word probably changed through the decades or it still confuses me
I enjoyed your video on oscilloscopes. I did not quite understand about the common mode and differential mode voltages on the output transformer. Could you explain that a little further. Thank you.
Differential mode refers to the voltage measured between two nodes, such as the voltage appearing between the terminals on a transformer winding. Common mode refers to the voltage appearing between these aforementioned points and ground. For example you might read 100mV between the output terminals on a transformer (differential mode), and also read that each of these terminals is ~60V above ground (common mode voltage).
For me this could not have come at a better time. One question, since chop as you have described it, does from what I can tell the same as alt. Why do you need the alt button at all. Surely chop can always be used? When would you use alt instead of chop? Thanks for this amazing video. I have gained so much from it. Another quick question. I understand in xy mode that your suggesting that from some clever signal generators the frequency can be output proportional to the ramp signal height which is then output to the X value on scope input. So that you can show a band of frequencies. Which is very clever and I want to try it out. But I did not understand how you explained it if you don't have a ramp function in your signal generator. I think you said you used a trigger on the sig gen to connect to X on scope? But did not really follow how that worked. Could you possible give me a few more pointers on how you do that or a link to a video or webpage that explains it in detail. As this was really interesting and I want to understand it. This is due to my inferior knowledge not your very good presentation! I suppose the first thing I will need is a sig gen that will sweep? I suppose they don't come cheap! Would it be possible to connect a MP3 player that had an audio file that plays through the whole audio range over a fixed time (say 1 second) (I only work on audio stuff) and some how feed that single into the X input of scope?
Chop will be dimmer at faster timebases as +kroplaaaa stated. Also, at certain timebase settings, you'll actually see the chopping action happening. In general, you always want to use ALT, and only use chop at the slower timebase settings where the trace-trace flicker is annoying. For generators that provide a sweep, but only provide a trigger pulse and not a ramp signal... In this case, you don't use XY mode. You use the scope in the normal way. If you set the generator to sweep in 100ms, then set the scope to 10ms/div (100ms for the entire sweep), and trigger the scope from the trigger pulse from the generator. Thus, the sweep on the scope is synchronized with the frequency sweep of the generator. I have two videos that show sweeps - they don't go into great detail into the setup, but they might provide you with enough additional background to help you out: ruclips.net/video/-A_DxsxPdeI/видео.html ruclips.net/video/1NdO07MljIk/видео.html For you MP3 idea to work, you would still need to have some way of synchronizing the frequency sweep with the sweep of your scope (so it always starts its sweep at the same time as your frequency sweep).
Thankyou, the chop thing was confusing now I understand what its for. Really so enjoyed this video. Okay with reference to the audio file. I was thinking of recording the full audio range over 1 second and then duplicating the sound clip about 500 times into one file. So every second for 500 seconds the full audio range would be output. So if I set time base to be 1/10 of a second then the full screen should give me the whole audio range (I think! I'm guessing) so every second the whole screen of whole audio range would show. But not sure how I would trigger it? Does this make sense or does this sound wrong. Also many thanks for the two links. Superb. This stuff is like gold to me.
kroplaaaa Thanks for this! I get it now. Its an extra control to allow you to view a fixed display when the swapping becomes annoying. But only on long timebase. That is so cool. I always wondered what it is was for and ALT for the matter! ha ha!
Hope you don't mind me asking. But do you think this would be any good? www.ebay.co.uk/itm/2MHz-DDS-Function-Signal-Generator-Frequency-Counter-Square-Wave-Sweep-TTL-Panel-/291252492495?hash=item43d00058cf:g:8fMAAOSw7NNUI5Mw
A younger colleague of mine used my Tek 2465 in single shot mode. He asked me if it was broken because "the screen only flickered once". I smiled and answered that it was because the memory wasn't "hooked up".
Thank you very much for the nice presentation. As you mentioned there is a shift in the frequency even when we use x10 probe to measure the oscillator circuit, then what would be the solution to eliminate such a shift for calibration of radio in a restoration job.
You'd only connect a scope to check to see if there are signals there, and their amplitude, etc. You don't align the stages that you're probing - you always probe downstream by a stage or two so that you don't load down the stage you are adjusting.
Hey Alan, I’m a ME junior and Ive enjoyed your videos and electronics as a hobby for years. If you could recommend a few electronics courses as relative electives, what would you recommend? The decision for ME vs EE was solely based off of my fear of abstract math(aka integral tests and other CAL 3 topics) I am just starting at the university level, do you think an EE is worth an extra semester to attain? I am on scholarships partially so that’s a consideration. Many thanks, Nick
The background audio was from the "demonstrator radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
can you elaborate more on what you have to do, or what NOT do, when you connect an O'scope to an AA5 radio so you don't damage either the radio or the O'scope. Thanks
I comes down to just a few things. Use an isolation transformer. Connect ground of the scope and probes to the negative side of the main electrolytic filter caps. Never connect probe grounds to different voltages in the same chassis.
Very informative lecture Alan, did you get a chance to use the AWG4162 in Beaverton ? Do you think the nice folks at Tek would let you do a full review and teardown ? Cheers
Nice Video. Actually all of your videos are excellent. I have the a "Triode Demostrator" made by Welch Scientific, and is in a black wooden frame just like your "trainer radio" you used. Is your made by the same company. I would to get my hands on one of those!!
To anyone wondering about the "background music": it is actually coming from the speaker on the demo board to our left. You can notice the scope signal changing with the music, which means it is hooked up to it and displaying what the radio speaker is playing. This was sort of a dumb setup to let the radio play during the lecture, but maybe it wasn't that loud to the audience because the camera was fairly close to it and turned towards it, plus the microphone is more sensitive and picks up more of the room sounds than the human ear. Chances are that the radio sounded at least twice quieter to the audience in the room than it does to us, but it was still a dumb choice to keep it playing throughout the lecture. I for one feel a little better and relieved to find out the source of it; it was more irritating while I thought it was done by some rude and careless student and that it was disruptive to the audience in the room. I also notice that the camera's live video was hooked up to another projector and displayed on the left side of the lecture board, which shows the additional mistake of not using giving another microphone or an audio recorder to the lecturer so that the recorded audio would sound a few times better. Clearly, the recording was arranged in agreement with the lecturer, so a better setup could and should have been made.
"IF" in radio terms refers to "intermediate frequency", a term used to describe the inner stages of a super-heterodyne receiver or transmitter. This is a fixed (no tunable) frequency filtering and amplification stage that processes the RF signal. In a receiver, the incoming frequency is translated (via a mixer) to the frequency of the IF. The IF stages filter and amplify the signal, and pass it along to the back end of the receiver for demodulation.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
I don't know why you didn't put a switch on the speaker or turn off the source transmitted signal. If I was sitting on the left side close to the speaker I think I would have moved even though I would be getting further from seeing what you were doing with the probe, etc. That being said it was a good presentation. Instead of buying a remote wireless mic you could just use a pocket voice record or an app on your phone and sync it in software later.
Recording of the session was a bit of an after-thought, so there wasn't a lot of planning involved in setting up the camera position, audio considerations, etc. I didn't realize that the demonstrator radio's audio was going to obtrusive, so I apologize if it was.
When you say beware of ground. Does this apply to a battery radio. For example the scope is mains powered so its ground is mains ground where as the radio is floating. So what precautions should one use to protect the scope when probing the radio? This is the one area that always confuses me wrt what is ground etc.
A battery powered radio is completely isolated - that's a good thing! You would generally connect the ground lead of the scope probe to the "reference" rail in the power supply system - usually the negative terminal of the battery system. Then, all voltages will be measured with respect to that rail.
Nice video, Just one question , both Radio and Oscilloscope are to be on Isolation transformer or Just the Radio? or Only Oscilloscope? Please advise Sir,
Alan, Is there a reason why when searching for W2AEW in you tube I get the EEVblog videos instead of your videos? In other words your video is on the screen but the adjacent videos are not W2AEW
![I.N "HALLUCINATION" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/n5B5q1Hwt_U/mqdefault.jpg)
37 years trying to understand the superheterodyne receiver I finally have a decent picture in my mind! Tank you so much for taking the time to film this video!!
Thank you. I might also show you this video (ruclips.net/video/Vf06HSR4LdY/видео.html) which illustrates and demonstrates how a superheterodyne receiver works.
@@w2aew You can be sure I will watch that one also, simply cant stop they are all GOLD!!
If it weren't for the noise of people and radio, I would watch this video many times over. As usual great video Alan.
I am grateful that someone took the time to document the class and post it given the resources they had at the time to do it with. Granted, the audio could have been better but I, for one, am grateful. Hands down this one video clarified the lack of understanding that I had with Ocilliscopes and audio signals.
PS, If you could redo the whole video from the beginning and have multiple, switched cameras, a properly EQ'd boom mic, picture in picture with clean transistions and ask everyone to remain silent till the end of the presentation. That would be great. 😉
Thank you Allan.
This is one hell of a course in Oscilloscope. I've been looking and watching "how to, use oscilloscope" videos for several years now this is by far the best one I have seen. Thank you very very much I'm going to save this and watch it again with the scope by my side, definitely more than once.
I've now seen an excellent electronic training course taught at Princeton for FREE! Likely with more knowledge than most professors! THANK YOU! I only wish I had even half this info in radio club meetings I've been to in the past. Most clubs you're lucky to get past "beginner" electronics training!
I love the AA5 training aid also!
I heard all that stuff, but I didn't listen to it......lock onto the instruction.......no complaints.....good video.....good enough to be worthwhile.....thanks, fm
Greetings, Alan!
To my knowledge, I've viewed all of your videos, and I must say, you are perhaps the finest educator I have ever seen, either on-line or in person! Your ability to clarify the most intricate electronics concepts has had a tremendous impact on my understanding of the topic, and I'm certain I'm just one of countless many you have enlightened! Thank you so much for all of your efforts in sharing your vast knowledge of electronics with others! Well done, Sir!!
well, thank you!! I am glad you enjoy my videos! Be sure to let me know if there is a topic that you would like to see in the future.
Now that you mention it, I was hoping you could shed some light on the topic of parametric equalization. While I understand the basic concept, the specifics of how and why they are designed still eludes me
somewhat; for instance, are there parametric eq's which incorporate shelving? Also, is it only frequency that can be adjusted in voltage-controlled filters, or is it possible to modify bandwidth or emphasis as well?
There are a couple of good topic ideas here. Suffice it to say that it is possible to design voltage control filters that include full parametric control (BW, Q, F). It is also possible to design voltage control shelving filters. I don't know what is commonly used in the pro-audio field - although I suspect that it is nearly all done in DSP these days...
I had no issue with the background noise. I've been to enough club meetings to expect these sorts of things.
More importantly, this video has taught me more about truly using my scope than any other source up to this point. Thank you for that!
Nice work.
73
I found the weird background music annoying and very distracting.
@@kurchak As would any sane person.
@@unlokia Microphone NOT close enough to Alan's mouth Result: we hear the sound from wall bounce... and direct from source... and reverb delay... makes for a cloudy image... difficult to decipher. Multipath distortion. Better would be a closer mic This is important\t material We need to hear it clearly Love W2AEW
0:36 "Scopes For Dopes" 😆!!! I need to check that one out myself!
I greatly value your videos. All of them are tremendously informative and illustrated with the formulas pertinent to understanding the concepts. Thank-you! God Bless
I see other comments about their equipment. I have many oscilloscopes. I have a Tektronics 453 I bought on E-Bay. It works... Perfectly as far as I can tell! It just smiles at me everytime I see it. And I smile right back. Great instrument!
I picked up a Tektronix 468 for $50. a couple of years ago. Wish I had seen this video when I was trying to figure out how it works... Think I still need to watch this video a few hundred times.... Thanks for sharing!
There's alot of information here that I would like to hear, but Ethyle Merman yacking in the background kills it for me.
I do wish the guy that is trying to act like he knows all the answers with his non-stop "right", "Yeah" and "Exactly comments would have keep quite. Even when Alan would have a slip of the tongue the fellow would change his answer like Alan did, Alan would say "no that would cause the signal to go up. the guy would say "you're right it would go up". Alan would catch himself and say "My mistake it should have been gone down." The guy then says "You're right it would have gone down." Please be still at the next session so we can hear the speaker.
Mmhmm, yep. Yeah. Mmhmm. Right. Yes it would.
You're right. He should be quiet next time.
Glad I wasn't the only one who noticed this. Was really annoying.
There's one in every crowd.
Glad im not the only one that was annoyed by the student that couldn't be quiet
This was great. I grew up in Hunterdon Cty and was originally licensed there in '57. I have been watching your VNA articles but recently picked up an HP 1740 scope (You should watch Dave's EEVBLOG on fixing one of these!). Of course I also have a fondness for tube gear and still have my Halli S38e, which is of course an All American Five. It seems to work all right but now I can fearlessly apply my HP probes to it (IF isolated). BTW I just ordered an Owon HDS272s to eliminate those ground issues.
73, Barry
VE7VIE and WV2J ex WV2ECZ
The subtract function will be useful on high ripple sets. Never thought of that. Thanks foe uploading and recording the lecture in the first place.
What a beautiful and professional presentation. Made my day.. Thank you for that, Alan!
Excellent presentation Alan!
I hear Harry James' Sleepy Lagoon" in the background along when the AA5 starts. Fitting for AA5 segment!
It must be the ham in me, but I just added a band pass filter in my brain. Didn't notice the radio or other noises at all, what did annoy me was the grunts and comments from the audience. Nice job as usual Alan, imparting your vast amount of knowledge to the less fortunate 😄 Cheers. Alan, GI0OTC
Just watching this excellent presentation even though I only have few idea of what he is talking about but just love listening to this intelligent presentation, thus the background noise and the distracting hhmm really meant nothing if anyone really wanted to listen to the concept and idea he is passing across. Good job.
I just muted the left channel and all the noise was considerably lower. :)
Very informative, but hard to stay with Alan because of 1) background noise / music and 2) fellow in the audience who needs to be heard every 30 seconds or so . . . "yeah" "oh" "hmmm" etc. Feels like they kept forgetting it was being recorded.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
Maybe next time just tune it off station so that it doesn't disturb the listeners.
Yeah audio not perfect... But it's free freaking amazing content!
It was the extreme close ups that were the most distracting for me. Great content though. I’d enjoy seeing more of this kind of stuff.
@@w2aew was a radio station? I thought it was a little transmitter of very old music from before the great war being played from a cellphone to a transmitter because there were no commercials, and no station like that i'm aware of out there. Anyway, it added a great ghost movie theme background and the guy right next to the camera was probably the main ghost :) I heard that they invented a "nagging" filter just to eliminate the funny sounds he made and give him his calories back
Great video Alan, would appreciate more like this I was glued i have been using scopes for years and found new thing i didnt know Very good
Just watched your video and have to say it was the finest well spoken video I have seen in a long time. Great job I have a NOS Sencore SC61 and after seeing your video I feel confident on using it now!! I also subscribed so looking forward to seeing more!
Thanks for doing this lecture and sharing it here, absolutely awesome content, definitely learned a lot more about my scopes.
Thank you very much for a great lecture, exactly what Ive been looking for for ages! (OK the radio noise is a little annoying, but I could "tune it out" ok). Thank you!
The most vital piece of equipment in any lab. The eyes of circuitry.
To all the complaints about background noise, talking, poor microphone placement, etc.. This was a presentation given by a guest speaker at a monthly meeting of the NJ Antique Radio Club. Not a professional lecture in a studio. Lecture halls are not the best environment for recording. Few clubs are lucky enough to hear a lecture by such a learned individual.
I bought a portable oscilloscope, I guess I won't be able to use it on my Admiral A31 radio for testing, since it's not to Ground ;-) Tks, great course !
I manage to fix it replacing all capacitors(keeping shell for antique reference), fixing AC wiring, all lamps were ok, I bought a second set of lamps for the future at a low price on e-bay....
Excellent and awesome instructional video, Thank you ! best one Ive found so far
Great job, always informative, always easy to listen to...thanks Alan.
Outstanding video on Scopes. Best I ever saw/heard. Thanks a ton for the effort and the information. Too bad your audio-visual guy had a radio program going next to the microphone thruout the entire presentation causing a somewhat distracting influence - which seemed to get louder as the presentation progressed.
I kept pausing the video and turning down the speakers until I finally realized it was something in the video causing the background noise. Unfortunately I could only make it though the 8min mark. It was distracting to the point I kept stopping and rewinding because I was losing track of what Alan was saying. It was almost disorienting. Sounded like singing then talking then like an old TV show. Unfortunate because I guarantee that presentation was excellent. Everyone who was able to partake in it was lucky.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
***** We always enjoy and appreciate your videos, Alan. A little background audio won't change that. :-)
I more than enjoyed the video Alan !! I learned a lot !! Your communication approach is excellent - perfectly pace; with highly focused content; and effectively sequenced for optimal assimilation. I really wish I had this video rather than my Electrical Engineering O'scope classes in college !! Thanks for all your postings !!
This type of video is worthy of a "studio" version. Hint Hint ;^)
Very interesting service video looking at signals along the IF strip.
The short explanation of probe comp was elegantly presented.
Alan ... Thank you for sharing all of your knowledge and understanding. Super Stuff!
73, Neil, K7WK
that is awesome. distractions do not mean much in the video, felt more like participating in lecture. only better than I had in my uni:)
Your presentation was extremely well done. I would greatly appreciate your help with one question: how do you know where to connect the ground lead of the probe to be safe? Do you analyze the circuit and identify ground, do you just use a good known ground in your home/office,...? From the end of the video where the radio is visible it looks like you put the ground clamps on a horizontal wire -- how did you identify this as the correct spot? Thank you.
The scope's ground is connected to the mains ground in the scope, and thus should only be connected to mains ground in the equipment you are testing.
Great video. Thank you. So is the Radio under test and all the mains measurement equipment including the scope plugged into the isolation TX? Ground lead clipped to chassis of radio?
@@lampmanpaul7459 Usually in such cases the scope is on an isolating transformer, though the equipment itself could be on it instead, but if the equipment during testing connects to something else which is grounded, you might find out after you damage something.
You can always connect a high impedance voltmeter and check for both AC and DC voltages between the scope's ground clip and the equipment's ground or zero point where you plan to attach scope's ground clip. You can also check if there is a current between (AC or DC) when connected via a sensitive ammeter and a resistor large enough (physically and resistively) to prevent a damaging current for such circuit (usually in miliamps).
Sometimes there is some small current between grounds regardless, and you could play it safe by using either a mid-value resistor (100 to 10k ohms), or a capacitor between 10nF and 100nF, or a 1k ohm resistor with a 100nF capacitor in series which provides DC/galvanic isolation and surge protection (through the cap).
Be careful and creative.
Thank you Alan for sharing this with us. Excellent video.
Very friendly presentation that even I understood :)
Many thanks for the clear presentation of the basics of measurement oscilloscope
I greet and as always look forward to the next interesting video.
I've been trying to learn on my own how to use scopes. I restore vintage tube receivers (Fisher especially) and a major realization I came away with watching this video is that I don't know WHERE in circuitry to probe so I can get usable images on the scope. This video helped. I sure would like to know where else can I go to learn more about where to probe.
Thank you for your very interesting lessons Alan, they are great and i personally learned a lot.
Just one little suggestion if i may... it would be very helpful for non-native English speakers like myself if you could use a microphone near your mouth to record the audio because the echo from the room, the noises from the radio, the random noises in the room, etc make it harder for us to understand your words (English subtitles would be even better but i guess it takes a lot of work). [This is not usually a problem in your "normal" videos]
Again, thank you!
Thanks for sharing Alan!
Fabuluous course ! I grew up building tube superhets with multimeters, rf/af signal tracers, rf/af signal generators, and yes even a wobbulator, but I never had a scope to see these waveforms visually !
Now that I have a good scope, you have inspired me to build a tube superhet again !
Thank you for giving me the joy of doing that !
One question though, in the output stage why dont we hear the ripple in addition to the AF signal ? You said it is rejected as a common mode signal, but I dont see how the single ended tube output stage does that.
Can anyone clarify ?
The ripple appears on both sides of the primary of the output transformer. The only thing that couples across the transformer is the AC *between* the primary inputs. The ripple doesn't cause the voltage across the primary winding to change, so it doesn't couple to the secondary.
Excellent video Alan. I have modern digital scopes but I still find myself using my old Tektronix or B&K analog scopes. Just can't beat the look of a warm glowing CRT. Keep up the good work. I recommend your videos often to newbies just getting into electronics.
One minor suggestion. If you ever do another classroom type session with a radio keep the radios volume down until its needed. With the camera being closer to the radio its audio level was almost higher than you at some points. Just trying to help. :)
Mike
Do you have a version without the radio / TV sounds in the backround? It makes it quite hard to focus on what you are saying, which is a pitty given the great presentation.
Outstanding lesson on a subject that is at the core of my main interest! As a 100% do-it-yourself'er...Due to all your videos, and AA5's, progress in this field has been at a slow/steady pleasing and enjoyable rate! Thanks for this video!
Great video, mega thanks to all involved......
Very nice presentation, thanks for sharing.
I learned so much from this video!!
*So Distracting*
There is a radio in the background of the audio, so hard to hear Alan.
Yeah, it was pretty annoying.
Alan, if you do any of these in the future suggest a wireless lapel mike--there is a lot of background noise and echo with the camera mike alone, and it's distracting...
Robert Calk Jr.
True.
But even given that, it was one of the best presentations I have ever seen on CRTs with or without the background noise. This is bookmarked in my notebook and I will also download a copy as its that outstanding.
MrMac5150
No I have not. Only just getting into it. Obviously not an electronics expert like yourself.
I soldier through the background noise, can't complain! great video
Blasted radio background noise makes this impossible for ADD types to concentrate!! Good appreciated content but I bailed at 49:20.
I forgot to mention - nice camera work
Another excellent video, Alan, I love your channel!
A very nice presentation, I learned a lot, thank you. You could make a video about your first scope one day. I looked up some Allen B DuMont oscillographs through image search and they seem to be interesting devices. Perhaps a video explaining how to control one of these old scopes and comparing it to a more modern one.
The best explanations. Thank you.
Between the noise of the radio in the background and some one talking next to the camera the distractions ruin the video. Brilliant idea. Thank you for trying.
That was good Alan, thank you!
Thanks Alan. That's a very informative lesson.
this is a great video lecture, i appreciate it very much!!
This is excellent - thank you
i would like to buy a demonstration radio like that....
Alan, another wonderful and informitive video! I find myself revisiting your videos from time to time after I encounter something familiar and then, boom, your video (on whatever the topic) comes through with clean, clear and concise info to help me better understand whatever it is I'm thinking about. As a little request, could you maybe do a video that hits on the do's and don'ts (especially with regard to analog or CRT scopes) with regard to how power cycling, run time and etc may have a detrimental impact on those appiances? IOW, I may be wrong, but short cycling (using your scope to look at something for maybe 5 minutes) from what I understand is bad? Somethig about quick heating and cooling cycles? Is it better to just keep it on and keep the trace dim when not in use? Maybe just old wives-tales? Also, I have a couple of Tek 24XX series scopes. I believe they have volatile memory that uses a battery? Those have an infinite life? What are the caveats and possible reprecussions of a memory battery going dead? Any insight? Enough stuff for an informative video? Just spit-balling, but something like that from you would be awesome! At any rate, keep those vids coming! Great stuff!
Excellent presentation. For slide 18 can you explain a bit more about the use of an isolation transformer? I have a Tektronix Technical Brief 'Floating oscilloscope measurements and operators protection' (51W-10640-1) that calls this an 'unsafe and dangerous practice and should never be done!'. Have I got this mixed up? Y
It's better to use the isolation transformer on the radio, keep the scope grounded. Then, when you clip the scope ground lead to the chassis - it becomes ground potential and a lot safer to work on.
@@w2aew Thanks Alan, perhaps the subject of a dedicated video? Also could you consider doing something on the use of a scope and signal generator for assessing balun performance (not the transmission line)? Y
@@w2aew I agree. Grounding an oscilloscope and using an isolation transformer should be the subject of a dedicated video indeed. It's not as intuitive or as easy as one might think when first starting out in radio repair. We'd appreciate it Alan!
I Gave up watching some 10 mins into the Video, I just. couldn't put up with the Radio or whatever it was that was close to the microphone... It Ruined what could have been a excellent video.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
Thank you... I figured it was the radio and hoped some one would have pulled the speaker or put a dummy load on it with a switch. The fellow talking next to the camera mic was just as distracting. I had so hoped to follow this lesson... brilliant idea, Thank you
vol ume con trol is the spec ial sec ret
Usually I'd be the first to be bothered by "little" things like the radio or the guy talking, but I found the talk engaging enough that I didn't notice either very much, or when I did I didn't care. Which is incredibly rare for me. I really hope you guys give this video another chance, cuz it has some excellent content from an excellent presenter.
I can totally relate, though. Something relatively small like that can be the difference between an amazing lecture or something that's completely unwatchable. Especially if you have ADD\ADHD as I have. Your brain just latches on to any little distraction and it becomes the entirety of your focus. It makes reading stuff damn near impossible for me, so channels like Alan's are truly a godsend.
Great video Alan! I’ve learned more electronics from you, Joe Smith and Paul Carlson and a few other you tubers and some good books than I did from any courses I ever had. I pretty much work on old guitar amps, audio gear and most recently tube radios. Lately I have been repairing my old test gear too. I have an old Tek 485 coming in today. That will be a challenge, but I think I’ve found the go to Tek expert on RUclips. 😎
Not familiar with Joe Smith. But Mr Carlson's Lab is a great channel. I loved his video on the tube op amp. I'm not big into RF or radio, but Alan's piqued my curiosity in them more than once. I can see being a lot more interested in them once I've learned more. EEVBlog and Big Clive were the two big ones for me when I first got into electronics a couple of years ago.
You work for Tektronix?! I knew it!! Something about your videos.
Tektronix always has and always will kick HP/Agilent/Keysight's ass.
...and I also just bought my second solid ink printer, another Tek win. ... and my 7623 is still in active service...
Could you do a video about safe guarding your oscilloscope and spectrum analyzer when measuring voltages and signals with older tube type equipment. I think that the scope is easy enough but the spectrum analyzer has a low impedance of 50 Ohms. Thanks.
Always great to review the fundamentals (as I seem to forget them so easily now a days!). 73 - Dino KL0S
I agree with you Trent. Really nice presentation destroyed with background noise. Not sure what the purpose of it was, but I could deal better with the gentleman every 30 seconds or so, than the background cartoon audio.
Great video once again, thanks!
thanks Alan....excellent lesson
What are the best (or your favorite) tektronix publications that you recommend for beginners, middle of the road, and advanced users? I still discover things in my 475 after all those years even though i have one of the most recent scopes. I will never understand why the first scope makers in history ( very probably tek) used the word "trigger" for what they used it for. The meaning of that word probably changed through the decades or it still confuses me
I enjoyed your video on oscilloscopes. I did not quite understand about the common mode and differential mode voltages on the output transformer. Could you explain that a little further. Thank you.
Differential mode refers to the voltage measured between two nodes, such as the voltage appearing between the terminals on a transformer winding. Common mode refers to the voltage appearing between these aforementioned points and ground. For example you might read 100mV between the output terminals on a transformer (differential mode), and also read that each of these terminals is ~60V above ground (common mode voltage).
For me this could not have come at a better time. One question, since chop as you have described it, does from what I can tell the same as alt. Why do you need the alt button at all. Surely chop can always be used? When would you use alt instead of chop? Thanks for this amazing video. I have gained so much from it. Another quick question. I understand in xy mode that your suggesting that from some clever signal generators the frequency can be output proportional to the ramp signal height which is then output to the X value on scope input. So that you can show a band of frequencies. Which is very clever and I want to try it out. But I did not understand how you explained it if you don't have a ramp function in your signal generator. I think you said you used a trigger on the sig gen to connect to X on scope? But did not really follow how that worked. Could you possible give me a few more pointers on how you do that or a link to a video or webpage that explains it in detail. As this was really interesting and I want to understand it. This is due to my inferior knowledge not your very good presentation! I suppose the first thing I will need is a sig gen that will sweep? I suppose they don't come cheap! Would it be possible to connect a MP3 player that had an audio file that plays through the whole audio range over a fixed time (say 1 second) (I only work on audio stuff) and some how feed that single into the X input of scope?
When you use chop at short timebases picture tends to be less bright.
Chop will be dimmer at faster timebases as +kroplaaaa stated. Also, at certain timebase settings, you'll actually see the chopping action happening. In general, you always want to use ALT, and only use chop at the slower timebase settings where the trace-trace flicker is annoying.
For generators that provide a sweep, but only provide a trigger pulse and not a ramp signal... In this case, you don't use XY mode. You use the scope in the normal way. If you set the generator to sweep in 100ms, then set the scope to 10ms/div (100ms for the entire sweep), and trigger the scope from the trigger pulse from the generator. Thus, the sweep on the scope is synchronized with the frequency sweep of the generator. I have two videos that show sweeps - they don't go into great detail into the setup, but they might provide you with enough additional background to help you out:
ruclips.net/video/-A_DxsxPdeI/видео.html
ruclips.net/video/1NdO07MljIk/видео.html
For you MP3 idea to work, you would still need to have some way of synchronizing the frequency sweep with the sweep of your scope (so it always starts its sweep at the same time as your frequency sweep).
Thankyou, the chop thing was confusing now I understand what its for. Really so enjoyed this video. Okay with reference to the audio file. I was thinking of recording the full audio range over 1 second and then duplicating the sound clip about 500 times into one file. So every second for 500 seconds the full audio range would be output. So if I set time base to be 1/10 of a second then the full screen should give me the whole audio range (I think! I'm guessing) so every second the whole screen of whole audio range would show. But not sure how I would trigger it? Does this make sense or does this sound wrong.
Also many thanks for the two links. Superb. This stuff is like gold to me.
kroplaaaa Thanks for this! I get it now. Its an extra control to allow you to view a fixed display when the swapping becomes annoying. But only on long timebase. That is so cool. I always wondered what it is was for and ALT for the matter! ha ha!
Hope you don't mind me asking. But do you think this would be any good? www.ebay.co.uk/itm/2MHz-DDS-Function-Signal-Generator-Frequency-Counter-Square-Wave-Sweep-TTL-Panel-/291252492495?hash=item43d00058cf:g:8fMAAOSw7NNUI5Mw
Great Video Alan, I have noticed there have been no new ones for a while, are you OK, or on vacation?
73
Larry
Just too busy with other life priorities, and my daytime job...
Supper was just concerned, look forward to more great videos in the future when time permits.
Regards,
Larry
A younger colleague of mine used my Tek 2465 in single shot mode. He asked me if it was broken because "the screen only flickered once". I smiled and answered that it was because the memory wasn't "hooked up".
...or it was the loose nut in front of the scope!
Spoiled by the modern wonders of digital technology.I think it would be cool tough to see a video with a full setup with a scope & camera.
Thank you very much for the nice presentation. As you mentioned there is a shift in the frequency even when we use x10 probe to measure the oscillator circuit, then what would be the solution to eliminate such a shift for calibration of radio in a restoration job.
You'd only connect a scope to check to see if there are signals there, and their amplitude, etc. You don't align the stages that you're probing - you always probe downstream by a stage or two so that you don't load down the stage you are adjusting.
I've used the "sniffer" inductive loop. I suppose it could still effect the oscillator circuit.
Hey Alan,
I’m a ME junior and Ive enjoyed your videos and electronics as a hobby for years. If you could recommend a few electronics courses as relative electives, what would you recommend? The decision for ME vs EE was solely based off of my fear of abstract math(aka integral tests and other CAL 3 topics) I am just starting at the university level, do you think an EE is worth an extra semester to attain? I am on scholarships partially so that’s a consideration.
Many thanks,
Nick
Thank you for all great info packed into one video! I will admit, when I started listening I thought my cell phone needed an alignment. (jk)
A little adjacent station interference? Or was it an image? IF stages a little too broad or staggered? 😆
Excellent !! Perfect
Hello there, thank you for the video, i learned a lot
Great presentation, but the radio show play in the back ground was very distracting through my speakers. Why was that present anyway?
The background audio was from the "demonstrator radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
*****
Yes, i enjoyed it very much. A little through half way when i had to stop. Will watch the rest later. Thanks for the reply.
It was a very good video, I just turned the sound off and watched it that way, I hope you do make another video like this one..... Thank you.
can you elaborate more on what you have to do, or what NOT do, when you connect an O'scope to an AA5 radio so you don't damage either the radio or the O'scope. Thanks
I comes down to just a few things. Use an isolation transformer. Connect ground of the scope and probes to the negative side of the main electrolytic filter caps. Never connect probe grounds to different voltages in the same chassis.
thanks keep up the good videos. Ienjoy watching them
Excellent stuff from Alan - too bad the backing music other noise make it difficult to take it in.
Very informative lecture Alan, did you get a chance to use the AWG4162 in Beaverton ? Do you think the nice folks at Tek would let you do a full review and teardown ? Cheers
Haven been to Beaverton recently, but scheduled to go in a few weeks.
Nice Video. Actually all of your videos are excellent. I have the a "Triode Demostrator" made by Welch Scientific, and is in a black wooden frame just like your "trainer radio" you used. Is your made by the same company. I would to get my hands on one of those!!
Yes, this demonstrator was also made my Welch Scientific. This one belongs to the NJ Antique Radio Club, and was restored by them several years ago.
To anyone wondering about the "background music": it is actually coming from the speaker on the demo board to our left.
You can notice the scope signal changing with the music, which means it is hooked up to it and displaying what the radio speaker is playing.
This was sort of a dumb setup to let the radio play during the lecture, but maybe it wasn't that loud to the audience because the camera was fairly close to it and turned towards it, plus the microphone is more sensitive and picks up more of the room sounds than the human ear.
Chances are that the radio sounded at least twice quieter to the audience in the room than it does to us, but it was still a dumb choice to keep it playing throughout the lecture.
I for one feel a little better and relieved to find out the source of it; it was more irritating while I thought it was done by some rude and careless student and that it was disruptive to the audience in the room.
I also notice that the camera's live video was hooked up to another projector and displayed on the left side of the lecture board, which shows the additional mistake of not using giving another microphone or an audio recorder to the lecturer so that the recorded audio would sound a few times better. Clearly, the recording was arranged in agreement with the lecturer, so a better setup could and should have been made.
You mentioned "IF" several times. Does that mean "Input Frequency"? Thanks, very interesting content.
Not a Radio guy, becoming a Scope pilot.
"IF" in radio terms refers to "intermediate frequency", a term used to describe the inner stages of a super-heterodyne receiver or transmitter. This is a fixed (no tunable) frequency filtering and amplification stage that processes the RF signal. In a receiver, the incoming frequency is translated (via a mixer) to the frequency of the IF. The IF stages filter and amplify the signal, and pass it along to the back end of the receiver for demodulation.
Awesome lesson!
Curious about where he put the ground clip. ... was kind of hard to see in the video
Excellent video, completely ruined by the background noise.
The background audio was from the "training radio" next to the scope. Unfortunately, even with its volume turned completely down, it still has some audio output. I didn't turn it off because it takes a few minutes to warm up, and that would have made it difficult to quickly make measurements. I'll have to invest in a wireless mic if I ever record a session like this again. Still, I hope you enjoyed the session in spite of the background audio.
I don't know why you didn't put a switch on the speaker or turn off the source transmitted signal. If I was sitting on the left side close to the speaker I think I would have moved even though I would be getting further from seeing what you were doing with the probe, etc. That being said it was a good presentation. Instead of buying a remote wireless mic you could just use a pocket voice record or an app on your phone and sync it in software later.
Recording of the session was a bit of an after-thought, so there wasn't a lot of planning involved in setting up the camera position, audio considerations, etc. I didn't realize that the demonstrator radio's audio was going to obtrusive, so I apologize if it was.
Fair enough, Alan. Like I said it was still worth watching. Keep the presentations coming just use a recorder in your shirt pocket next time!
+Tony Hunt You would make a horseshit ham radio operator.
This will be good. Comments afterwards.
excellent thanks, more please
When you say beware of ground. Does this apply to a battery radio. For example the scope is mains powered so its ground is mains ground where as the radio is floating. So what precautions should one use to protect the scope when probing the radio? This is the one area that always confuses me wrt what is ground etc.
A battery powered radio is completely isolated - that's a good thing! You would generally connect the ground lead of the scope probe to the "reference" rail in the power supply system - usually the negative terminal of the battery system. Then, all voltages will be measured with respect to that rail.
I guessed that would be the case. Many thanks for confirmation.
Excellent!
Nice video, Just one question , both Radio and Oscilloscope are to be on Isolation transformer or Just the Radio? or Only Oscilloscope? Please advise Sir,
Only the radio.
@@w2aew Thank You Sir !!
@erikderuiter7 Yes, It's socket is separate with good ground. Thank you for info
Alan, Is there a reason why when searching for W2AEW in you tube I get the EEVblog videos instead of your videos?
In other words your video is on the screen but the adjacent videos are not W2AEW
It's been 4 years and I'm sure that you've figured it out. Algorithms that are sometimes based on money and politics, views and likes.
Can you squelch off the radio Noise in the background? It is most annoying. 73 de N6YOC
great video good explanation thanks
I'd imagine that AM radio demonstrator is quite a rare thing nowadays.
I think there are two at the Vintage Radio and Communications Museum in Connecticut. They are rare indeed.
Alan is there a way to learn how to build a spectrum analyzer or converting an old analog oscilloscope by building modules?
Probably the best documented homebrew spectrum analyzer can be found here:
www.science-workshop.com/