VE3MAL

joined 1 year ago
[–] [email protected] 1 points 10 months ago

On HF, unfortunately, physics is going to keep you from having high speed data. The Shannon–Hartley theorem puts a ceiling on the maximum bitrate of a channel in the presence of noise. If you are on HF with your 100w transceiver and a dipole antenna, your signals are always going to be weak enough on the other end of a skywave contact to limit your data throughput. Even given a magical ham prodigy that invents the best mode imaginable, it's going to be Kbps, not Mbps. If you want to learn about the development of open source, higher throughput digital modes for HF, I highly recommend David Rowe's blog on the development of FreeDV over the years. There's even a recent move to general data in addition to digital voice. However, we are talking about single digit Kbps digital. There are some other modems used by the Winlink folk that are a little higher. The drop of the baudrate limit will just remove an artificial contraint, and headache, on that development.

On line-of-sight VHF and up connections, it gets easier and easier as you have higher gain antennas pointed at each other and lower natural noise figures.

[–] [email protected] 1 points 10 months ago

Bandwidth doesn't put a hard limit on bitrate either. It's one variable, but there's also SNR (See Shannon). With a fixed bandwidth, you can have low bitrate and excellent low-SNR performance (think of Olivia), or you can have higher bitrates, and require stronger signals. For practical purposes though, you are not going to get highspeed internet on HF. But that's what sharing is like. 🤷‍♂️

[–] [email protected] 4 points 10 months ago (1 children)

It's a neat idea, but could be implemented entirely in software with a RTLSDR. Not my cup of tea, but I'm all for absolutely ANYTHING that gets more activity on V/UHF.

A longer term project goal for me would be a SBC and a couple RTLSDRs with a good antenna that simultaneously does APRS igating, streaming audio of all the local repeaters and a few simplex channels, and notifications like this project, and like the "adventure radio" project that uses CTCSS tones to trigger alerts. I think it would be a nice service to provide for locals. The only "trick" is that RTLSDRs can only simultaneously decode within a 2.5mhz window, so it would probably require a little scanning to cover everything, or too many sticks. Doing a project cheaply, but effectively, encourages copy-cats.

[–] [email protected] 3 points 10 months ago* (last edited 10 months ago)

50 meters is enough for a 80m 1/2w dipole. And yes, google a "fan dipole" - you can hang multiple dipoles below each other with as little as a few inches of separation. However, the dipoles interact with each other, and getting it right gets more troublesome the more you do.

[–] [email protected] 1 points 10 months ago

Neat idea. Odd that those diagonal telescoping rods don't interfere with the yagi pattern?

[–] [email protected] 1 points 10 months ago

I agree, a low power SWL license scheme would be fantastic. If you think you can convince your representative to advocate for it, go for it. Currently, even low power community FM is barely tolerated as a license class, and regulators tend to think of SWL as REQUIRING that the targeted audience be non-domestic.

[–] [email protected] 2 points 10 months ago (2 children)

God the Klingon thing was silly. Do we need an explanation as to why the TOS ship had plastic, 1960s themed furniture? Do we need an explanation for improved camera resolution over the years? Why did we need a silly explanation for the improvement in makeup artistry so many decades later? And the explanation doesn't even work. Genetics don't work like that. It's taking themselves too seriously. Either ignore it, or hang a lantern on it with an inside joke once, and be done with it.

[–] [email protected] 3 points 10 months ago (2 children)

It mirrored the contemporary idea of the "End of History", where all the existational crises were done with, the federation (was basically moving into a time of refinement rather than having to worry that the experiment might still utterly and completely fail. TNG was basically one long, slow lesson of why that was a flawed notion. You don't build a cruise liner, fill it with families, and then intentionally send it into the kind of peril that regularly befitted the Enterprise D. In retrospect, it was completely ridiculous.

[–] [email protected] 1 points 11 months ago (2 children)

That's basically what shortwave pirates are. Usually former ham transceivers modified to transmit out of band. The cost of licensing and building a shortwave broadcast station are immense. And there's the pesky problem of finding advertisers when the license scheme basically requires you to at least look like you are targeting non-domestic audiences. Hams have occasionally purchased time on existing transmitters when it's cheap, but as far as "experimental modes" go, it would typically have to be something that can be modulated by an AM transmitter.

[–] [email protected] 1 points 11 months ago (1 children)

It cannot be parity because, unlike the fiber Internet, it's fundamentally limited by the HF spectrum and the cost of this type of operation. Most traders will not have this option and will get fleeced by those with the resources.

[–] [email protected] 4 points 11 months ago

Agreed. This isn't a responsible use of spectrum, unlike, say commercial shortwave broadcasting. This practice is purely about gaining a pay-for-play advantage in high frequency stock trading over traders that can "only" communicate across the country via fiber internet links. No net benefit, even for the stock traders, who will be hurt by this more often than they can take advantage of it. Sure, sell HF licenses to commercial users, but this is a bad idea.

[–] [email protected] 5 points 11 months ago

fyi, nearly everyone that succeeds in achieving morse proficiency recommend strongly against any sort of visual cues like this. It's an auditory "language" and adding visual interpretation steps just adds cognitive load and hurts in the long run. It may be fine if your goal is to learn max 5 words per minute or something extremely slow.

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