bobvan13

6 ms·

1.
by bobvan13 8y ago
Thanks for noticing this post. It covers many of the questions that arose in the comments on my Part I post. It also details two more shortwave trading sites around Chicago.
2.
by bobvan13 8y ago
Good point, a one-time pad is not needed. Either way, the likelihood of loss between TX and RX means that you can't advance the cipher as bits arrive. I'm thinking you'd have to advance based on GPS-sync'd clocks. Given
3.
by bobvan13 8y ago
Listening is the easy part. But the sender would be foolish not to strongly encrypt what they send. Are you really "listening" if all you get after decoding is pseudo-random bits?
4.
by bobvan13 8y ago
A one-time pad is the right idea. I would send it on fiber at night before the markets open and then use bits from it as the market trades. A few MB per day would be plenty, given the dialup-like speeds of shortwave. That would go through a
5.
by bobvan13 8y ago
There is some latency savings because the radio path is far straighter than the fiber path, even considering the ricochetting off the ionosphere and the earth. But the bulk of the latency savings comes from the fact that radio waves move at
6.
by bobvan13 8y ago
The license applications list a range of frequencies where operation is allowed. Indeed, many SWLers have documented such transmissions, e.g. https://www.youtube.com/watch?v=ySzpz8LWrjA The trouble is that when you do liste
7.
by bobvan13 8y ago
Yup, it stands alone well. I give it a strong recommendation for accuracy and storytelling.
8.
by bobvan13 8y ago
Right. A shortwave link would be used in addition to a fiber link, not as a replacement for it. Assuming ACKs aren't latency sensitive, they could flow back over the fiber.
9.
by bobvan13 8y ago
Yes, it has to bounce, but the number of times it bounces is dictated by the takeoff angle, as is the path length of each bounce relative to ground traversed. You aim for takeoff angles around 12 degrees. Since cos(12 degrees) ~= 0.98, ther
10.
by bobvan13 8y ago
Yes, well said. I think you're making an important distinction. Shortwave is old technology, but combined with SDR, this is a novel application of it AFAIK.