Radio Receivers at TL-5

[MThompson016]

When my grandmother passed away last year, her sons looked through the house, and my dad got grandad's old radio. We think he got it brand new in the Air Force in 1951. It's a heavy, luggable tube radio, that still works. Could you use something like this in your campaign?

http://travellersandbox.blogspot.com/2017/08/communications-at-tech-level-5.html

 

[jcrocker]

That's a great radio.

There's a lot of TL-5 worlds that would make those - I'd say that they might not be good for vehicles, since a big bump with the filaments hot could break the wire, but they'd be popular for home sets. I understand good tube sets have good sound quality.

 

[epicenter00]

I hate to be That Guy who has to rain on every parade, but while the idea of people building TL5 radios sounds pretty good for low-tech worlds, I feel it's one of the big pitfalls (not necessarily a flaw) of the Traveller universe; I think the only worlds that'd have vacuum tube technology would be some backwater autarky that is determined to develop everything themselves and not trade with the outside universe at all - even information. I don't think anyone's ever tried it on Earth, but if you have the sum of modern scientific/technical information, I think even if you have had to start from a stone age setting, you could skip large portions of intermediate technologies that historically happened because we were stumbling blind to develop new things.

In essence, a vacuum tube is the worst of all worlds in a TL based system of different markets (worlds) with different TLs: Tubes are hard to construct, requiring quite a bit of industrial infrastructure (some of it pretty specialized). The end result is heavy, temperamental, failure prone, and because they're failure prone expensive in terms of having to carry around spare tubes. A starship's machine shop, if its capable of making a vacuum tube, is going to be capable of making an electronic radio which will likely be lighter, more reliable, and less demanding of power supplies.

I think there'd be a large gulf between very simple to construct radio equipment, like crystal radios, particularly Russian work like the "crystodyne" technology and so on - that stuff can be gussied up in a machine shop. Yeah, the performance isn't great, but it can be made in primitive conditions. Then you'd jump to electronic radios.

 

[nobby-w]

When my grandmother passed away last year, her sons looked through the house, and my dad got grandad's old radio. We think he got it brand new in the Air Force in 1951. It's a heavy, luggable tube radio, that still works. Could you use something like this in your campaign?

http://travellersandbox.blogspot.com/2017/08/communications-at-tech-level-5.html

Electronics is one thing that I would expect to be cheap and compact enough that folks would just import it. By about TL7 a two-way radio is a cheap, handheld device unless you need a really powerful transmitter for some reason.

Something like this is unlikely to exist in any environment where a world capable of manufacturing transistorised electronics was within a commercially viable jump range - say (for argument's sake) within the same or any adjacent subsector. Unless you were somewhere really isolated or cut off for some reason, this sort of tech is unlikely to be cost-effective to manufacture. You might conceivably find this on an interdicted world where the inhabitants have no choice but to use local technology.

In practice, I think that goods within 1-2 TL of the highest local tech level would be pretty widely available and imported on most worlds in any given region, regardless of local tech level. Most goods like this would be imported unless some good-enough local substitute was available at a competitive price. A valve radio of this type would be 10-100x more expensive than a radio of 2 tech levels higher.

As an aside, I'll also argue that by early 20th century (i.e. a TL5 environment) the materials and manufacturing technology to needed fabricate integrated circuits with a wet etching process already existed. Transistors weren't invented until the 1940s, but the basic technology to fabricate them had been available for some time before they were invented. A hypothetical TL5 interdicted world could possibly also have also made transistorised electronics.

 

[aramis]

There was a conceptual break through, that, in the modern earth came a bit too late for non-specialized use of vacuum tube technology...

You can make them VERY thin. As in, millimeter or so.

Very, very EMP resistant, too.

Actually, there's an IEEE Spectrum article (link to article) talking about how to make micro-scale vacuum triodes in photo-etch Additive/Subtractive manufacture... allowing for vacuum tube IC's...

when they die, it will be from air getting in...

 

[Timerover51]

That's a great radio.

There's a lot of TL-5 worlds that would make those - I'd say that they might not be good for vehicles, since a big bump with the filaments hot could break the wire, but they'd be popular for home sets. I understand good tube sets have good sound quality.

Thousands of vacuum tube radios did very nicely in thousands of Sherman Tanks in World War 2, along with lots of them bouncing around in Jeeps and assorted other vehicles. Then there were the thousands of vacuum tube radios that took off in aircraft in the North African Desert or Pacific Islands with temperatures in the 90s and went to well below zero at 25,000 feet.Then there were the thousands of vacuum tubes that made up part of the proximity fuze sued by the U.S. and Great Britain during World War 2, that were first fired from a high-velocity anti-aircraft guns or an artillery piece prior to functioning. All of the ground, naval, and aircraft radars in World War 2 and Korea used vacuum tubes.

The reason that good tube radio sets have good sound quality is that they can be tuned to improve performance, not like a transistor set up. I can remember tuning the radio and TV to get the best reception from the broadcast station. That is not possible with transistors. I can remember going to the store and checking the TV tubes on a tube tester to determine which one needed to be replaced. Try that with a modern TV.

In My Traveller Universe, there are planets that refused to import any technology that they cannot maintain with the planet's resources. A lower Tech Level planet is not apt to have a lot of starship traffic, and waiting for spare parts to repair an air raft may take a couple of months, and then the hope has to be that the right part is delivered. That is not a guarantee.

 

[jcrocker]

Thanks for the reminder about the hard use some of the tubes got - do you know, were those just standard tubes that would have been sold in civilian sets a few years before, or were those 'ruggedized' versions?

Also, another feature that gave them good sound quality compared to early transistor sets, is the fact that they were analogue devices, with natural 'decay rates' in the signal. A human voice or played music isn't just on or off like a digital transistor, and it took a while before they could emulate that in the transistor sets.

 

[Timerover51]

Thanks for the reminder about the hard use some of the tubes got - do you know, were those just standard tubes that would have been sold in civilian sets a few years before, or were those 'ruggedized' versions?

Also, another feature that gave them good sound quality compared to early transistor sets, is the fact that they were analogue devices, with natural 'decay rates' in the signal. A human voice or played music isn't just on or off like a digital transistor, and it took a while before they could emulate that in the transistor sets.

The proximity fuze tubes were standard civilian hearing aid tubes, which were tested until they found the make that worked best. The tubes in the military sets were pretty much off the shelf components, as no military could afford any pre-war research on making vacuum tubes more rugged. They used what they could get.

 

[JimCook]

I hate to be That Guy who has to rain on every parade, but while the idea of people building TL5 radios sounds pretty good for low-tech worlds, I feel it's one of the big pitfalls (not necessarily a flaw) of the Traveller universe; I think the only worlds that'd have vacuum tube technology would be some backwater autarky that is determined to develop everything themselves and not trade with the outside universe at all - even information. I don't think anyone's ever tried it on Earth, but if you have the sum of modern scientific/technical information, I think even if you have had to start from a stone age setting, you could skip large portions of intermediate technologies that historically happened because we were stumbling blind to develop new things.

In essence, a vacuum tube is the worst of all worlds in a TL based system of different markets (worlds) with different TLs: Tubes are hard to construct, requiring quite a bit of industrial infrastructure (some of it pretty specialized). The end result is heavy, temperamental, failure prone, and because they're failure prone expensive in terms of having to carry around spare tubes. A starship's machine shop, if its capable of making a vacuum tube, is going to be capable of making an electronic radio which will likely be lighter, more reliable, and less demanding of power supplies.

I think there'd be a large gulf between very simple to construct radio equipment, like crystal radios, particularly Russian work like the "crystodyne" technology and so on - that stuff can be gussied up in a machine shop. Yeah, the performance isn't great, but it can be made in primitive conditions. Then you'd jump to electronic radios.

Actually vacuum tubes would be far easier to make than transistor based electronics. Getting the chemistry of the junctions right is difficult. Going to IC chips takes a lot of industry, crystal forging, photoresistive masks, UV steppers, and so on. A vacuum tube requires some metal work, a glass blower, and a vacuum pump.

 

[nobby-w]

Thanks for the reminder about the hard use some of the tubes got - do you know, were those just standard tubes that would have been sold in civilian sets a few years before, or were those 'ruggedized' versions?

Also, another feature that gave them good sound quality compared to early transistor sets, is the fact that they were analogue devices, with natural 'decay rates' in the signal. A human voice or played music isn't just on or off like a digital transistor, and it took a while before they could emulate that in the transistor sets.

Early transistor devices were also analogue - I guess you might be thinking of pulse width modulation, which is used in some audio equipment (more on this below).

The quality of valve amplifiers came from the distortion when the amplifiers were in saturation. Transistors will clip the waveform when they are at their maximum capacity (i.e. fully open). In extreme cases this causes distortion as the waveform gets clipped. Imagine taking a waveform and masking off the extremes, then playing the resulting waveform. This is effectively what happens when transistors are in saturation and produces an effect that sounds like Dalek voices - this technique was originally used to do the Dalek voices in Doctor Who.

Valve amplifiers have different characteristics in extremis - they don't saturate suddenly like transistors, but the amplification sort of tails off. The effect is a different perceived sound, and is popular in guitar amp circles as it sounds like a traditional valve amplifier from the '50s or '60s.

Pulse width modulation works by supplying a constant voltage but varying the length of the pulse to control the power. It is used in audio equipment today to drive speakers, particularly digital systems.

 

[jcrocker]

That could be it - it was from an article I read about 20 years back, but what you say sounds familiar. Thanks!