Understanding how the Superhet / Superheterodyne Radio Works 

Hopefully I managed to succeed!

Me toooo! I needed this so bad. I need to fix my radio and be able to explain it since it is the last of its kind. It has no paperwork so I’m stuck reverse engineering it and it’s above my pay grade. With this video I’m working my way up the payscale.

Glad you found the video useful.

Sadly there were many legal cases over patents associated with radio around this time. It was really sad to hear about your father’s history, but it was the sort of thing that happened. It is a great shame that good people like your father lost out in such a big way.

Similar to the guy who invented the Philips screw. Bravo to your father, a hard working dreamer. His inspiration is part of his legacy.

Glad it was helpful!

​@@ElectronicsNotes Perfect explanation short and straight to the point

@@noblesimfukwe153 Thank you.

Glad you liked the video. Thanks for your comment.

That is a great summary of how the superhet radio works.

Glad we helped.

Thank you.

Thank you.

That’s really great - well done. I’m very glad the video helped.

Glad that you found the video useful. Normally the Google translation works well, but I can imagine that for specific technical terms it would not work so well. That is a shame. Thanks again for the comment.

Glad to have been able to help.

Back in the day when the superhet was invented, it used more valves / tubes than the more usual tuned radio frequency, TRF radios and hence it was much more expensive. As a result it was little used for several years. Only when costs of valves fell, they used indirect heaters which meant they could be powered by supply / mains transformers, and also the improved performance they offered was needed. At this point their use started to take off.

John, the first radio receivers offered to the public were crystal sets. They didn't have amplifiers, and they didn't have reliable tuning. Yes they were cheap. They could never have been the basis of a broadcast radio industry. When amplifiers became workable, based on vacuum tubes, radios were better and still cheap, but it was extremely difficult to tune them to a given station. The superheterodyne radio simultaneously made tuning easy and reliable and also made the amplifiers better. The added expense, more tubes and a more complicated tuning capacitor, was more than made up for by how much better the radio was. It is still the basic circuit for almost anything that picks up radio waves and uses them. That would include radar. It's possible now to amplify the radio wave and sample it at a high rate, converting each sample into a number represention the instantaneous voltage, or current. Then a computation can simulate the mixers and filters. It's still a superheterodyne radio, but entirely digital.

I hope this page will give you some answers: www.electronics-notes.com/articles/radio/rf-mixer/rf-mixing-basics.php

The reason is that an antenna is often used with a ground. I admit balanced antennas do not need a ground.

Really glad you found it useful.

Edwin Armstrong is generally credited with the invention of the superhet principle, but others made signify advances toward it. You can read more about how it was developed on this page on our website: www.electronics-notes.com/articles/history/radio-receivers/superheterodyne-radio-receiver.php

@@ElectronicsNotes дякую вам за вашу відповідь до мене,я ще робив схему ,так у самому генераторі використовувався кварц,цей приймач робив набагато якісніше,ніж без радіодеталі кварц, його чутливість була 1 мкв/м кв

I hope the video helped.

@@ElectronicsNotes дякую вам

Thanks very much for your comment. It is good to get feedback. Thank you. However I have to disagree with your comment that a receiver that uses one mixing stage to convert a signal down to a fixed frequency IF is not a superhet or superheterodyne receiver. The term superheterodyne comes from supersonic heterodyne, meaning that the mixing process is above audible region. Also the definition of superheterodyne or superhet receiver given by Wikipedia disagrees with your summary. The definition given by Wikipedia states that a superhet radio "is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF)." There is no mention of it being only a single conversion superhet, etc Also the Collins dictionary defines the superhet as: "a radio receiver that combines two radio-frequency signals by heterodyne action, to produce a signal above the audible frequency limit. " Again there is no mention of how many conversions. Similarly many books, RSGB, ARRL, Terman, and many many others all define the superhet as a radio where two RF signals are mixed or heterodyned together to produce a signal at a new intermediate frequency where it is filtered. Normally the IF is at a fixed frequency as fixed frequency filters are far more effective. Whilst heterodyning, mixing, or multiplication - call the process what you want, is the process used. A superhet or superheterodyne radio is one where the incoming signal is converted down to an intermediate frequency state, or stages and it is then demodulated. Soem receivers will convert the signal directly down to the base-band, and these are often called direct conversion radios - the is a technique often used with many simple radios, and it is also widely used for applications where a digital signal is being processed and it is converted down to give I and Q components for further processing. I hope this clarifies the situation.

@@ElectronicsNotes I realize your response is click bait, but I will respond none-the-less. You are wrong. First, I checked with Wikipedia before commenting to make sure my facts were correct...not that my 40 years in radio would ever take a back seat to Wikipedia - a collection of articles that anyone can edit - in my mind. Second, please tell me where you have seen a "supersonic heterodyne?" The word sonic refers to the air (or water) pressure waves that produce sounds audible to the human ear. The word "sonic" has absolutely nothing to do with electronics. Third, the examples you gave do not disprove what I said. All examples given allude to the heterodyne process, but do not specify the number of mixer stages. I should not have to remind you that the prefix "super" refers to something over and above that which is normal; in this case, it refers to more than one mixing stage. There is nothing "super heterodyne" about a single heterodyning stage. The term "direct conversion receiver" can mean many things based on the frequencies we're dealing with. Many of us have made "crystal" (one diode AM) receivers as kids. SSB receivers when used for communication at 10-15 MHz or below can be "direct conversion" since there is no need for an RF IF at that frequency (but they still use heterodyning - Sideband receivers almost have to). My first real job was repairing and modifying Yaesu 900-series Amateur radios as well as the Kenwood TS-series. Most owners wanted 11-meter capability which was disabled by default. Anyone here as old as I am knows exactly the radios I am referring to - and that was in 1983. And BTW, I used to keep versions of the ARRL handbook until I was 40. And since you chose to show your lack of knowledge, I will call you out: "Normally the IF is at a fixed frequency as fixed frequency filters are far more effective." I am not aware of any receiver that doesn't have a fixed frequency IF (or more than one if there is more than one mixing stage). Are you? Designing an IF filter for a varying IF would be a nightmare indeed. Usually it is the local oscillator frequency (or frequencies) that varies. If you know of a receiver with a "varying IF" please enlighten me. If the "IF" in question is audio frequency don't bother. We live in an age where knowledge and common sense are being redefined. I stand by my original statement - that "super" heterodyne receivers have more than one mixing stage - and that is my final answer.

@@royshashibrock3990 Thank you for your reply. However I have to continue to disagree with you over your definition of the superheterodyne radio. My answer was **** not click bait**** as it did not refer back to any of my sites, videos, etc. I was just trying to back up what I believe to be correct. Trying to answer your points in turn: I agree that Wikipedia is not 100% reliable, but for most things it is not bad - if there is an error, someone will edit it. The term supersonic heterodyne I found in The Superheterodyne Radio by Alfred Witts, 5th Edn 1944. This book also explains the superheterodyne principle as one where the incoming signal is converted down to a lower, generally fixed frequency for better selectivity and amplification - no mention of two conversions. I agree with you that super does mean above and beyond, but as the explanation I gave before, it refers to the fact that the heterodyning is supersonic, or above the audible range and not more than one conversion which is referred to as a double conversion superhet. You also refer to my "lack of knowledge" with regard to a fixed frequency IF. I included this statement for a variety of reasons. The first is that possibly the first superheterodyne radio was developed by Lucien Levy. He used a variable frequency IF, but of course this was later improved upon by Edwin Armstrong who used the more normal fixed frequency IF. This worked much better because the fixed frequency filters were much better and he could optimise the performance of the radio using a fixed frequency IF in terms of its stability and amplification. I have also been involved in the development of a superhet radio system for a highly sophisticated professional satellite communications system where I was a key development engineer. The system used a fixed frequency down conversion from the satellite frequency to a variable IF around 1GHz. We used a tracking filter at this frequency before the signal was again converted down to a fixed IF around 70 MHz where the majority of the filtering took place. I also wanted t accommodate the situation where external or additional converters may be used to extend the range of an existing radio. Here the RF side of the main radio, effectively becomes the first IF and this is variable in frequency. As there are many different topologies that can be used with the superhet, I wanted to make sure all aspects were accommodated. I have also sorted out additional references where the superhet radio can be a single conversion. Many early broadcast radios are described as being superhet radios. The PYE PCR was a receiver without BFO and it is described as a single conversion superhet: www.pyetelecomhistory.org/prodhist/military/military.html#Communications_Receiver_Type_PCR_PCR2_ The EKCO A22 was described as a 3 valve superhet: www.vintageradio.nl/schema%27s/Ekco-a22.pdf You may also want to look at this video explaining the superhet radio where it talks about the basic principle and it gives a single conversion radio. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qfAPNLioBnI.html You may also remember within my video that I had some very eminent professionals: a well respected university professor from UCL who is also a keen radio amateur, the CEO of Silicon Labs, a major producer of ICs for the connectivity market (they also produced a large number of FM radio ICs) and someone from ICOM UK. All these people talked about the superhet radio and at no time was it said that more than one conversion was needed. I have spent a lot of time, pulling out references to support what I said, so this is the last reply I will give.

I thought I would just have one last reply in view of your comment about me which said: "And since you chose to show your lack of knowledge." I have now looked up several additional references: Radio Receiver Technology Principles, Architectures and Applications, by Ralf Rudersdorfer, pub Wiley 2014. This book describes a "Single Conversion Superhet: which only contains one mixing or heterodyning process. The demodulator could use a product detector, but it was also discussed as use with a diode envelope detector, etc. It then goes on to talk about multiple conversion superhet radios. Radio Frequency Electronics: Circuits and Applications by Jon B Hagen, pub Cambridge 2009. This book refers to the superheterodyne receiver with a single conversion used for FM reception, i.e. no multiplication or heterodyne process is used for FM demodulation. It continues to talk about a single conversion superhet radio, and then mentions multiple conversion radios as well. But the point is that a single conversion process is used and the radio is still called a superhet. Technician's Radio Receiver Handbook by Joseph J Carr, pub Newnes 2000. This boom refers to single conversion superhet radios. Obviously a product detector can be used, but Joe Carr also talks about AM envelope detection and FM demodulation under the title of the single conversion superhet banner. As, not only the eminent people I interviewed talks about the superhet radio as one which converts the signal down to an intermediate frequency, and no mention of it needing to require two conversions, and the references I have referred to, in addition to the references I posted yesterday of broadcast AM radios with a single conversion being referred to as superhet radios, I think this must be fairly conclusive evidence that a superhet does not require more than one conversion. If you need further references than I could provide these as well if you want.

Because that is the way we Brits tend to do it.

@@ElectronicsNotes But you still could leave out saying the nought... it's redundant.

@@drstrangelove09 Because it's trivial, and nobody cares. You could have not made a childish and irrelevant comment that contained nothing but a redundant opinion, but you didn't.

@@perrycrowe999 whatever... your opinion, we do not agree... go away with your finger waving