The Superheterodyne Radio

It's also called Condensator in Russian

On a sidenote: In German, a capacitor is called "Kondensator", interesting to know that that terminology was also used in English once.

Amazeballs vidya!

Although nowadays tuning done in software, super heterodyne is still used: e.g. I work for Silicon Labs, and some, if not all of our radios are definitely superhet. The demodulation is much more advanced (and purely software), and it can differentiate between image and carrier, making image rejection even better (look for IR calibration if you're interested)

András Bíró

One thing you missed is why they developed the Superhet design, the Superhet was developed as earlier radios had upwards of 4 tuning knobs to lock in on the frequency to set each individual local oscillator in the radio so a channel could be heard, it was quite common place until the development of the superhet to write down the tuning information for each knob to just listen to one station. The reason the multi oscillator design was preceding as oscillator circuitry was in its early stages and to tune in the high frequency as you put it, was to slowly step down the frequency to be able to be listened to. The superhet was developed to reduce complexity in the design and make it easier to tune stations, but in saying that the multi-stage mixing was commonplace on a number of radios to get better signal resolution and that the multi-stage mixing process was more used on FM modulated signals due to the higher frequencies involved but as technology progressed and oscillator design moved to a crystal basis a single IF frequency was used.

Paul Fisher

Thanks for the fun science tour for Christmas morning (it’s Christmas already, here in the future :-) ). I too like the old schematics, and enjoyed just as I was thinking “cycles per second” to explain beat frequencies in came the schematic with its 445kc! Merry Christmas, Ewen.

Ewen McNeill

Thanks for another great video -- I never heard of this technique and it's awesome!

Paul Schuur

Did you notice that there were new caps in the shot below the chassis? :) This was the first antique radio I ever messed with, and it was the first to be re-capped, as well. All with basic capacitors from Fry's, but then again it's essentially an All-American 5 so there weren't many to begin with. It's been working pretty good ever since!

Technology Connections

I've repaired antique radios for the last 40 years and the issue is the capacitors 99% of the time, occasionally a tube goes bad but that is actually fairly rare, the poor tubes get all the blame, but the paper, wax and electrolytic capacitors are pretty much nearly always the REAL culprit! - By the way, it's the capacitors in newer stereo equipment as well, such as the late 70's silver face audio components. So don't just plug in that old radio, amplifier or other vintage electronics gear - replace the caps first, then you don't smoke the hard to find tubes, transistors, transformers, tweeters, etc. needlessly! Some parts that folks are blowing up this way are not available at all.

Bill Basch

I learned about the heterodyne effect from boats and airplanes with multiple engines generating beat frequencies when not in perfect sync. While usually not altogether unpleasant, (It adds some charm to the sounds of bombers in old WWII movies and the like, IMO) it was always better to eliminate or at least minimize them since they can cause extra vibration damage over time. Thanks for another fun video, and I hope your {INSERT HOLIDAY NAME HERE} and following non-specific calendar-based celebration are quite pleasant!

This was very good (“something all physicsy,” ha!). BTW your panning shots are so good.

Marcin Wichary

Nicely done!

Funny that the radio is called "Transitone", but is in fact a tube radio, not a transistor radio ;-)

MrHammond