Jason - VE3MAL

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Joined 1 year ago
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Cake day: July 11th, 2023

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  • 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.


  • 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. 🤷‍♂️


  • 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.





  • 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.









  • If you don’t have trees and want an easy, portable solution. Buy a $20 20 foot “crappie” fishing pole on your favorite online retailer, and run a 20m 1/4wave vertical wire up it. Add between 4 and 8 radials on the ground, and craft up a simple guy system with some rope and tent pegs. Cheap, lightweight, and highly effective, especially at this point in the solar cycle. Cut some shorter wires for higher bands and you can pick and choose which one to hoist on a given outing. The only downside is that right now, specifically js8call activity is still heavily on 40m. You will make boatloads of ft8 contacts on 20 though.


  • An EFHW can be oriented as an inverted-V, it’s just that it’s fed at the end rather than in the middle (at the top). If that’s how you set it up, the main difference is some transformer losses in the EFHW, but it can operate on all harmonics rather than just odd harmonic bands. A center fed inverted v may be a little more tolerant with regards to tuning the length. Centre-fed is going to be more “idiot proof” in that respect and possibly easier as a first antenna.



  • I think watching all those hours may actually change your brain wiring. Hopefully for the better.

    I couldn’t really tolerate the animated show, or Babylon 5. But everything else has passed through these neurons at one time or another. Fortunately, it’s been so many years, I sometimes come across an episode I can’t remember and it’s like getting a new one.

    Strange new worlds is amazing. It feels actually true to TOS, without just being nostalgic. I feel like Gene Roddenberry would be so happy to see it, and recognize it as his universe far more than any of the other 21st century trek.