Transistor radio 1950s11/14/2023 ![]() ![]() The classic five-tube superhet design was a model for the transistor radio (same IF frequency, too), but is now being overtaken by direct-to-baseband, zero-IF approach. Armstrong (he also developed the superregenerative receiver and FM radio!). Radio has also been a major driver of advances in receiver architectures and mass-market design and manufacturing, based on the single-conversion superheterodyne technique invented by Maj. Despite its many limitations, broadcast radio is still the easiest and quickest way to reach millions, and the incremental sourcing cost of supporting additional users is zero, since the broadcaster doesn’t need additional infrastructure. In fact, some of the newer cars don’t offer an AM radio even as an option, due to nasty EMI issues as well as lack of driver interest, see the Wall Street Journal article “ Your Tesla Can Go Zero to 60 in 2.5 Seconds But Can’t Get AM Radio.” Thus, while the audience is shrinking, the technology for bringing radio to the masses has improved dramatically in performance and cost. Depending on which report you look at, AM/FM listenership is stagnant or shrinking (despite some framing of survey questions to get more favorable answers, IMO) see References, while credible data on the shortwave audience is just not available. Broadcast radio (AM, FM, and even Short Wave ) is not a growth area in terms of audience, especially with younger prospective listeners, and radio certainly doesn’t have the dominant share of mind and role it once had. ![]() ( side note: that old radio was well-built and has survived all sorts of abuse that was back when Sony products were well-designed and built, a situation which substantially changed for the worse few years later, IMO.) ![]() Now I have radio which not only offers basic AM/FM reception, but also does much more, with synthesized tuning and digital readout, for far less that I think that SONY unit cost back in the day – and all in a package about the same size. The multi-branded L-258 AM/FM/SW radio is the same size as the Sony unit, but is far cheaper while adding many digital and user-friendly features and capabilities. I estimate the Sony radio, which measures about 6 × 3 1/2 × 1 ½ inches (15 × 9 × 4 cm), retailed for around $25 in 1970 dollars (and there are still some used ones for sale on eBay…go figure that one out!) I did a quick web search and found that the unit dated back to around 1976, so we’re looking a unit that is over 40 years old and still works, although not as well as when new.Īmong the many sites I found which called out this radio, was the Radio Museum, and it had some photos of the TFM-6100W which were better than the ones I took see Figure 2. ![]() First, of course, it needed a quick forensics review, so I opened it up – just two simple screws – and saw large discrete components (by our standards) including capacitors, inductors, ferrite rod antenna and, of course, transistors (nine of them), all on a single-side, low-cost phenolic circuit board. (Image source )Īlthough I don’t like to discard old stuff that still sort-of works, it was time for the radio to go. This 9-transistor Sony AM/FM radio is over 40 years old and still works, although tuning and audio quality are not as “crisp” as they were decades ago. ![]()
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