3 ms·

Depends on your primary goal. Digital signals don’t carry very far without significant infrastructure. “Come the bomb” quadrature encoding will not be helpful f

Depends on your primary goal. Digital signals don’t carry very far without significant infrastructure. “Come the bomb” quadrature encoding will not be helpful for wide area universally accessible communication…but analog signals distributed by transmitters that are still very much alive and active at every radio station (and many emergency facilities and private residences), or that can be made cheaply out of broadly available and very simple components, with wavelengths long enough to get bounced off the ionosphere, and zero dependence on large scale built infrastructure…

hilbert42 2y ago
"bounced off the ionosphere, and zero dependence on large scale built infrastructure…" Exactly, it seems the present generation is unfamiliar with the way traditional AM radio works. It's really worrying, as it demonstrates how very easily knowledge can be lost across only just a few generations.
jdietrich 2y ago
You can bounce a digital signal off the ionosphere much more easily than an AM signal - see the first in my comment.
- hilbert42 2y ago
  First, to your earlier point that my comment was factually incorrect and that AM is is incredibly inefficient. I was not comparing or even discussing modulation techniques here, that's a totally separate matter, in fact I agree with your comment. The point I was making is that AM is not only simple (a crystal set/germanium diode will demodulate it) but more importantly it is the 100+ years of experience and especially the huge amount of existing AM infrastructure throughout the world including millions of car radios—including those in undeveloped countries which is important—that are key to why there's a push to maintain the service through legislation. I've already made comments to that effect in other posts so I'll leave it at that. Second, I agree with your point here about digital signals and the ionosphere. Similarly, it's why I'm a great fan of Digital Radio Mondiale (DRM—badly named given its other meaning). In fact, I'm upset and rather annoyed that it receives so little attention and that it's made so little penetration into HF bands but there's little I can do about it except whinge. Unfortunately, just because something is good or better doesn't mean it gets adopted (remember VHS won out over Betamax although the latter was better, also Windows versus Linux is another comparable case). If you look at history often technical standards (and improved methods) are adopted after the event. Also, grandfathering technology is commonplace whether we like it or not. I learned this years ago when sitting on several preparatory committees for WARC/WRC and also when involved with television standards for industrial work. Things that make obvious sense technically often don't get up because of political and economic considerations—and stubbornness by those with entrenched views. It's a big problem (arguments over standards are common, are often heated, and invariably messy—and often the outcomes end up overly compromised). That brings me back to my earlier point about AM, other systems are better but other factors stop them from being universally adopted.

hilbert42 2y ago

"bounced off the ionosphere, and zero dependence on large scale built infrastructure…" Exactly, it seems the present generation is unfamiliar with the way traditional AM radio works. It's really worrying, as it demonstrates how very easily knowledge can be lost across only just a few generations.

jdietrich 2y ago

You can bounce a digital signal off the ionosphere much more easily than an AM signal - see the first in my comment.

hilbert42 2y ago
First, to your earlier point that my comment was factually incorrect and that AM is is incredibly inefficient. I was not comparing or even discussing modulation techniques here, that's a totally separate matter, in fact I agree with your comment. The point I was making is that AM is not only simple (a crystal set/germanium diode will demodulate it) but more importantly it is the 100+ years of experience and especially the huge amount of existing AM infrastructure throughout the world including millions of car radios—including those in undeveloped countries which is important—that are key to why there's a push to maintain the service through legislation. I've already made comments to that effect in other posts so I'll leave it at that. Second, I agree with your point here about digital signals and the ionosphere. Similarly, it's why I'm a great fan of Digital Radio Mondiale (DRM—badly named given its other meaning). In fact, I'm upset and rather annoyed that it receives so little attention and that it's made so little penetration into HF bands but there's little I can do about it except whinge. Unfortunately, just because something is good or better doesn't mean it gets adopted (remember VHS won out over Betamax although the latter was better, also Windows versus Linux is another comparable case). If you look at history often technical standards (and improved methods) are adopted after the event. Also, grandfathering technology is commonplace whether we like it or not. I learned this years ago when sitting on several preparatory committees for WARC/WRC and also when involved with television standards for industrial work. Things that make obvious sense technically often don't get up because of political and economic considerations—and stubbornness by those with entrenched views. It's a big problem (arguments over standards are common, are often heated, and invariably messy—and often the outcomes end up overly compromised). That brings me back to my earlier point about AM, other systems are better but other factors stop them from being universally adopted.