This is a brilliant angle on explaining heterodyning. Your eBook is also *exceptional* on clarifying the kinds of details that trip people up when trying to follow How It Works. Best way to grade an engineer's knowledge is on how effectively he or she can explain something truly complex to someone else. Your generosity is greatly appreciated.
Thanks for this excellent video showing how the intermediate frequency is generated and further amplified in the following stage of this beautiful made easy schematic diagram. It is a fantastic way of explaining difficult concept of the etherdyne principle of the radio. ä
The 455kHz filters are bandpass filters right? What would be the passband of these filters? If they were very narrow you wouldn’t be able to use the output for audio right? Their passband has to be wide enough to cover the range of frequencies across which the original RF frequency signal into the antenna is Amplitude Modulated right? How wide would this passband be?
The 455KHz is a very narrow peak. The audio information is on the amplitude of the 455KHz carrier. How does a Diode, Demodulate AM Amplitude Modulation ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ej1KCkE_RsY.html
The link is in the ABOUT. Here is the information. Password is allamericanfiveradio ru-vid.com?event=channel_description&redir_token=QUFFLUhqa2hhVTRycWdJd1FUbTFCZWNmdGtQNlZCRmEzd3xBQ3Jtc0tuOFQ2bFhRcWdjdUdIcUREcnZFaHc0M2xURGhITVRuWDE2cGlDakdYUF9uODktNzc3TVRJTWdROUt6R3NLN2lla3hFS2lIM0RnOXR1dXFxMGx2cUNtWDhXb1Zvc2RCbGQxTThoendmN2E5R0lJdmI0Yw&q=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp%2Fview%3Fusp%3Dsharing
+vibra64 It could. Today's digital radios usually use Phase Lock Loop (PLL) circuits. The PLL circuit is simpler and does not require a change of frequency. When superheterodyne was first invented PLL was known but it was too expensive to produce, that is no longer the case.
Sorry , ... one more strange question... ....that got stuck in the back of my mind for long time ! Do you know who and How started to measure those Units ... Like .... ohm, Farad, etc ... Ok... * 1 meter ... At least - We see exactly what constitutes a length of * 1 meter... ... Yep.. But ... How those early electroEngeners and scientists created * 1 Volt or * 1 Ohm... * Ampere ... And in particular 1 picoFarad .... I mean ... It is mindBoggling to imagin 1 billionth of something ... ... Isn't it ??? How they established those First units and how they could measure them ? ... I mean ... How Tesla could measure 10 megaHerz frequency or similar stuff. ... ??? I mean...they had wooden plinth equipment and they didn't know that ELECTRON even exists, .... So ... how they can Establish: 1 Farad ... and then measure 1 picoFarad ... or let's say : Capacitor of : 10 nano Farads. ... 🤐🤔🤪😬😱🤐 ...
This would be a good place to start. Georg Ohm nationalmaglab.org/magnet-academy/history-of-electricity-magnetism/pioneers/georg-ohm/ Michael Faraday nationalmaglab.org/magnet-academy/history-of-electricity-magnetism/pioneers/michael-faraday/
This method of adding and subtracting colours to show what happens with the frequencies is a brilliant demonstration. This is the clearest explanation I have ever seen. I know you made this 6 years ago, but thank you so much for posting it.
Excellent any easily comprehensible demonstration Rick. Exemplary! It was also wnderful to finally virtually meet you at the Burlington Mini Make Faire. Yes, i also am a subscriber to Dean's "Hackaweek" channel. Between your voice and you describing being an engineer at three radio stations, it was simple to figure out. Nice display there at the Faire! Did you have fun? 73s my friend, Tom
saudações brasileiras ao amigo.........................por favor como posso conseguir o seu e-book? gostaria de te-lo....................muito obrigado
Hi there! I understand fairly well about how the local oscillator mix frequency with the selected antenna emf carrier where the output will be 455Khz and you get the sum and differences which are the 4 output signals on the plate of 1st tube. But I can't get my mind to understand how even at the antenna as carrier waves from a whole HOST of signals hitting the antenna, WHY don't you get "destructive interference" (Lost Information) due to incidental frequencies cancelling out each other. Like, if you have two or three "water" waves coming to shore, sometimes they add up to produce a larger wave...and sometimes the peaks and valleys cancel each other and you don't get a peak or valley. With a multitude of radio frequencies hitting the antenna, why isn't that information LOST on the input grid of the 1st tube? Do radio waves not behave like water waves in that respect? Perhaps it's just that simple, but I need to hear from someone that knows...lol! Perhaps not matter how many radio signals there are in the area, "radio" waves always combine, but never destroy? Thx AllAmericanFive or anyone who can help me correct my thinking!
Interesting question and observation. If you through two rocks simultaneously into a pond, the waves from each will interact with each other and depending on the distance from each other they will add and subtract at various points. The waves produce this way are of the same frequency. This means that they can influence each other as much as possible. This is why there cannot be two radio stations on the same frequency in the same coverage area. The distance between radio stations and the difference in frequency of each radio station are carefully chosen to minimize interference between stations. I helped take care of a 50,000 watt AM station that was daytime only, from sunrise to sunset only. This station had to go off the air at sundown because at night the sky wave travels much farther. This station, in North Carolina, was on the same frequency as a 24 hour station in Boston. At night if the North Carolina station did not go off the air it interfered with the station in Boston. So the time of day is also very important along with distance and frequency.
The link is in the ABOUT on my RU-vid site. Here is the information for the eBook. I hope you enjoy and find the information useful. PASSWORD is allamericanfiveradio drive.google.com/file/d/1HHmaWYr7UMACfmS4W5uL6PADoem2KlRp/view?usp=sharing
Well done Rick, I need a refresher on PLL. I heard that the new Icom IC7300 does away with superht. I wonder what they're up to, most likely all digital like sillyfones. Don
Great video demonstration. Wish we had the internet, You Tube, Photoshop, et.al 50 years ago when I was learning all this. It would have been so much easier! 73 KM4JA
AM intermediate frequency is 455KHz, FM intermediate frequency is 10.7MHz. Same process different frequencies. FM Radio Signal Tracing ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-a5qa4OFockA.html FM Detector Demodulator ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-tmhhltKM9z8.html FM Demodulation and Detection, Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lYjIGni4Z7g.html FM Stereo MPX Decoder Circuit and Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ACqEiFHCofI.html Searching My AllAmericanFiveRadio Channel ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4k7ByHqh8Js.html
Hi Richard, you have some of the best comprehensive video's and explanations out on YT. I have been struggling grabbing exactly what the hetrodyne was doing within the mixer/oscillator sections and your videos really helped. Thanks! Just a few questions. If you were to put a scope on the plate of the first tube, what would it look like? Also how/why is the modulation maintained in the bottom 455K signal?
Thanks pappafrito A scope on the first plat would already be almost only 455KHz because the the primary and secondary are very sharply (high Q) tuned. I'm not sure what you mean by “ bottom 455K modulated signal” and that's OK, I want to answer your questions. You do have the right idea about the purpose of the highly tuned I.F.'s, “ignoring anything else”. The tuned I.F.'s only passes the 455KHz modulated signal. Ask your questions. Here is a few videos that may help you on AM Demodulation. AM Detector Demodulator ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8AWscuGSjsY.html AM Radio Demodulation Oscilloscope Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pKA0TPdnHg8.html How does a Diode, Demodulate AM Amplitude Modulation ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ej1KCkE_RsY.html
@@AllAmericanFiveRadio Thanks so much for responding and the links. Sorry my question is probably confusing as I tried to edit it after the fact. Basically I'm experimenting with building a low voltage tube am superhet radio (using a 12fx8 and 12al8). I’m fairly clear on the demodulation side. The mixer however I'm not quite clear on as to what is actually happening in the mixer (visually). I understand that you will end up with Rf, Rf+LOf, Rf-LOf, and LOf in the mixer (and also other frequencies??). I am not clear at all how/why that all happens in the mixer visually. So if I’m at least understanding the basic principle correctly, If I wanted the tune my radio to 640am, I would tune a gang capacitor so that both my tuner tank circuit resonates at 640Khz AND so that my local oscillator oscillates at RF+455Khz (1.095 Mhz)? Then put that signal through a highly tuned 455K filter to get the IF to the next stage amplification. Then why/how does the 455K signal maintained the modulation through and out of the mixer? Or are all of the 4 separate frequencies equally modulated? I know Rf is obviously modulated. I can see how Rf+LOf could be modulated with the audio. This is where I’m getting lost… lol! Thank a million, love your vids!
@@PatrickInCayman Thanks pappafrito I'm thinking about how to show the mixing process. Might make a video. It has to do with Harmonics. I'm doing about three or four things (projects). SO if you do not hear from me in a few weeks, send me an email. I want to answer your questions. Rick
+bigpops Back in the late 1940s, 50s, and 60s, yes. The five vacuum tube set. The better radios had six tubes, it had an extra tube in the frontend, an RF amplifier
AA5R, Joernone did a video for a tube-based AM transmitter that was connected to a design of yours. I'd like to try this project and was wondering if you'd mind sending me the schematic and parts list. Best, Tony
+bigpops This link has the video, pictures, and wiring diagram with all the parts listed. Also email questions from cameramanlink and my answers. www.richardmcwhorter.com/AM_Transmitter/
