I can confirm the comment about lugging batteries around; my father worked for the original Curry's store in the UK before the war, and aside from folks bringing in batteries for recharging, he used to have to collect and deliver them on his bicycle (Old Man Curry was too cheap to have a delivery van).
Another story from that era was the gas-powered radio - I didn't believe it until I saw the repair manual - literally a gas burner heating up a bank of thermocouples! Thats what you call letting the set warm up..
Speaking of Zenith Transoceanic, my dad got one too, in 1966. Did you look at the schematic? It had a really basic AM section, which includes the SW bands of course, and it had a single IF of 455 KHz for all AM bands. Not the best way to keep intermodulation products under control.
Not only that, but in 1966, schematics were still drawn as if they were for tube circuits. So just as tubes are usually shown on top, so were the transisators of the 1966 Zenith Transoceanic.
I guess I'm saying that the Zenith Transoceanic sort of followed the same simplicity of design paradigm as this Radiola, although of course from the superhet era.
Then we got a Grundig multiband radio with dual-converion IF ...
@BobsView, 11/15/2013 - "TRF Forget about that one":
I'd say that's pretty accurate statement ... Looking the orthogonal arrangement of the tuning coils, the designers were doing their best to reduce coupling across the stages. I can only imagine tuning across the dial, headphones on and coming across a strong station while having the volume up to pull in a far away station.
I liked the linear arrangment of the tuning dial. The designers went to some extra effort to design and build a nonlinear capacitor.
Generally one section was for the Local Oscillator, one for the Mixer and the one for the Antenna input.
Superheterodyning came along later, no local oscillator in this beast. There are three stages of tuned RF amplification. The ganged cap was an improvement over earlier models that required each section to be tuned seperately. That kind of made you stick with one station, as it was slow and difficult to change stations.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.