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Interesting. But as a non-ham I find the article chock full of ham jargon which leaves me completely lost. > What happened to take an esoteric mode designed fo

Interesting. But as a non-ham I find the article chock full of ham jargon which leaves me completely lost. > What happened to take an esoteric mode designed for multi-hop E skip on VHF and overnight turn it into a worldwide phenomenon across all bands from 2200m through 70cm? In other words, what makes FT8 a killer app? Indeed. What does make FT8 the killer app? Anyone care to break this down in layman's terms that an EE with basic radio knowledge can understand?

sevensor 8y ago
So, multi-hop E-skip is a way that the signal can propagate through the ionosphere. (E-layer skip: https://en.wikipedia.org/wiki/Sporadic_E_propagation https://en.wikipedia.org/wiki/Sporadic_E_propagation). 2200m and 7cm are wavelengths. FT8 is a digital mode that can transmit a very restrictied amount of information -- basically your callsign and where you are. Exchanging this information is enough for a contact, or QSO. The debate is about whether it's still about communication when you can't really talk to people using FT8. Edit: And contacts are basically how hams keep score. You used to send postcards to the people you'd talked to. Old hams have binders full of them.
- MisterTea 8y ago
  Ah, I think I understand. I remember hearing the term, "shooting skip", which I understand as slang CB users used for talking to people past the horizon using the ionosphere to bounce the radio waves. So if I understand correctly this is a game hams play where you try to skip your signal as far as possible and see if you get a ping? If I am understand this properly, this successful exchange earns you a point and the old timers used post cards as score keeping, as once the ping was established they could each mail each other. I assume FT8 is text only?
ianburrell 8y ago
FT8 and other weak signal modes can work with more noise and less signal than conventional modes. Which makes possible to communicate with the current poor HF propagation, or with lower power devices and longer distances. It does this by using low bandwidth (50 Hz), low bit rate (6 bit/s), and error correction. The other special thing about FT8 is that it only does contacts, with binary messages for doing the exchange.
- jpmattia 8y ago
  > FT8 and other weak signal modes can work with more noise and less signal than conventional modes I'm a little surprised that FT8 is better S/N than conventional mode of morse code, but then I didn't think in terms of S/N back when I was active in the 70s/80s (btw: Straight key! I finally build a keyer after 5 years of straight key, and then went off to college and didn't have another QSO for many years. :( Edit: Regard QSO, Do folks even use Q signals anymore?
  - tasty_freeze 8y ago
    These low bandwidth / low power modes are mathemagic, extracting signals that are well below the noise floor. Redundancy, forward error correction, and low baud rates are the key. In morse, the baud rate is low, but you get one chance at each symbol and that is it. With these new modes a small set of bits is sent in a highly redundant fashion such that you can recover the whole message even if you capture only, say, 30% of the bits, not necessarily contiguous.
  - deleted 8y ago
    [deleted]
  - hatsunearu 8y ago
    morse CW is pretty bad in terms of BER because it's hard to create a robust automatic decoder, not to mention OOK (which is morse essentially is for this purpose) is very poor against multipath interference.

sevensor 8y ago

So, multi-hop E-skip is a way that the signal can propagate through the ionosphere. (E-layer skip: https://en.wikipedia.org/wiki/Sporadic_E_propagation https://en.wikipedia.org/wiki/Sporadic_E_propagation). 2200m and 7cm are wavelengths. FT8 is a digital mode that can transmit a very restrictied amount of information -- basically your callsign and where you are. Exchanging this information is enough for a contact, or QSO. The debate is about whether it's still about communication when you can't really talk to people using FT8. Edit: And contacts are basically how hams keep score. You used to send postcards to the people you'd talked to. Old hams have binders full of them.

MisterTea 8y ago
Ah, I think I understand. I remember hearing the term, "shooting skip", which I understand as slang CB users used for talking to people past the horizon using the ionosphere to bounce the radio waves. So if I understand correctly this is a game hams play where you try to skip your signal as far as possible and see if you get a ping? If I am understand this properly, this successful exchange earns you a point and the old timers used post cards as score keeping, as once the ping was established they could each mail each other. I assume FT8 is text only?

ianburrell 8y ago

FT8 and other weak signal modes can work with more noise and less signal than conventional modes. Which makes possible to communicate with the current poor HF propagation, or with lower power devices and longer distances. It does this by using low bandwidth (50 Hz), low bit rate (6 bit/s), and error correction. The other special thing about FT8 is that it only does contacts, with binary messages for doing the exchange.

jpmattia 8y ago
> FT8 and other weak signal modes can work with more noise and less signal than conventional modes I'm a little surprised that FT8 is better S/N than conventional mode of morse code, but then I didn't think in terms of S/N back when I was active in the 70s/80s (btw: Straight key! I finally build a keyer after 5 years of straight key, and then went off to college and didn't have another QSO for many years. :( Edit: Regard QSO, Do folks even use Q signals anymore?
- tasty_freeze 8y ago
  These low bandwidth / low power modes are mathemagic, extracting signals that are well below the noise floor. Redundancy, forward error correction, and low baud rates are the key. In morse, the baud rate is low, but you get one chance at each symbol and that is it. With these new modes a small set of bits is sent in a highly redundant fashion such that you can recover the whole message even if you capture only, say, 30% of the bits, not necessarily contiguous.
- deleted 8y ago
  [deleted]
- hatsunearu 8y ago
  morse CW is pretty bad in terms of BER because it's hard to create a robust automatic decoder, not to mention OOK (which is morse essentially is for this purpose) is very poor against multipath interference.