FT8 TEST on air "DXpedition Mode" on 6 and 7 March !

Just to help you out, you quoted my original comment.

 

Another aspect to EmComm: Plain and simple guys, when someone doesn't know CW and the solar cycle sucks so bad SSB won't make it, FT-8 WILL MAKE IT!

 

I love FT-8!
See you on the waterfalls!

 

Yabbut, how much good can it do for Emergency Communications?

 

i dont know the exact number but in the bandwidth of a single ssb conversation maybe 24 or more ft-8 contact potentials can be seen in the band activity box which is refreshed every 15 seconds. ft-8 isnt handy for rag chewing or passing amounts of info but to generate a quick list of who is on the air for possible contact via another more useful mode i for one can see the utility. setup wsjt-x, tune in to 40m and witness the amount of call signs that fly past. it can be huge
Carl

 

Just a thought about the history of our hobby and service:

Can you imagine the first time someone figured out how to work "phone?" They had been running CW for decades at that point and of course spark before that point.

If you think CW guys think we are cheaters now because we do not have to learn code to get a license, what do you think they originally thought of the first phone guys? Was there a fight over a new mode called "phone?" I imagine there were guys that thought it was the end of the hobby. It was just not how they liked to communicate.

They eventually got over it or died.

 

I think everybody was excited about using voice back in those days. But lordy, it went all to hell when SSB came about

 

Inside a standard 2,7 kHz SSB bandwidth, the 50 Hz FT8 bandwidth fits 54 signals with no overlaps, although you will probably not be able to decode all of them. FT8 and the other weaks signal modes in the WSJT-X package have powerful decoding algorithms. Therefore, the signals may overlap considerably to the extent that they can be decoded even when the signals are transmitted almost exactly on top of each other. With overlaps you can just think of a high number FT8 signals inside the 2,7 kHz SSB bandwitdht. Quite efficient, even compared to CW, although FT8 has a lower "baud rate" at comparable bandwith. However, most of us get confused trying to decode CW signals on top of or close to each other, while FT8 and the other weak signal modes are quite good at .

Bear in mind that in standard mode, the JT65 frequencies starts 2 kHz above the FT8 frequency (e.g. FT8 @ 7,074 and JT65 @ 7,076), so it is advisable to keep your TX frequency within 2 kHz of the displayed frequency, which will allow for 40 FT8 signals with no overlap, and a much higher number of FT8 signals with overlap. Regrettably, we regularly see that FT8 signals spreads well into the JT65 frequencies, and that is not OK.

73 de Frode LA6VQ

 

I remember reading how they thought about SSB and you're right, the world was coming to an end! I imagine it was the same way for AM originally.

 

Umm, sure at 13 characters per exchange and no error correction and not including any callsign identification. Sheesh. Sorry, but FT modes are NOT a good choice for actual communications, i.e. Message traffic.

 

thanks for the specifics.
Carl

 

I think we should probably not overextend the good things about FT8. Yes, it can get a signal through at low power and difficult conditions, but JT65 and JT9 is clearly better, while they take 4x the time. The minimal messages conveyed in WSJT-X modes cannot be expected to have more than very limited use in emergency communication and only in quite unique situation. When SSB doesn't work and CW isn't known, quite a few elegant digimodes, like Olivia and Contestia, have been developed for weak signal conditions. Although they require better SNR than the WSJT-X modes, they have excellent abilities in getting a signal through, and at "baud rates" and particularly message contents well above FT8, JT65, JT9, etc. Applications like Winlink add to it.

Remenber, the WSJT-X modes are made for very specific purposes. Message content and baud rate (except for the fast scatter modes) are not among them. So, let's praise FT8 for what it is good at, and be very realistic on everything else.

Same thing about FT8 Dxpedition mode: made for very special situations, with very specific instructions, which will require time, understanding and practice to be followed by all users. It looks promising, although still only in beta testing. Time will show how it fares; my prediction is that it will "go live" working well, level the field between big guns and small pistols, teach us many interesting lessons on propagations, and be fun.

73 de Frode LA6VQ

 

It's interesting to see that the new DXpedition mode is already in use and most FT8 users can't communicate with the DX station.
Currently, TY7C, The Benin dxpedition 2018 By F6KOP, is on 40 meters at the lower end of the fT8 'band' and 283 from the bottom.

The instructions of the TY7C QRZ web page state that they will use dxpedition mode.

It's really too bad that the author did not use a PW to prevent the use of the FOX mode until the final release of the package.

 

With open source code, I guess a password would soon be removed. A password would also be much more exciting to break, so I believe it wouldn't help much.

The FT8 DXpedition mode is developed for very specific and limited use, involving multi-operator high volume DXpeditions to very rare locations (like KH1 Baker for which it is intended), involving a very high number of callers, heavy pileups, etc. As such I find it difficult to beta test without exposing it to similar conditions, like last week's test. Now the test results must be evaluated, bugs fixed, more testing, more bug fixing, and eventually a general release, to be used by big dx-peditions to really rare entities.

The FT8 DXpedition mode is specifically not to be used in ordinary FT8 frequencies, and therefore comes with an intrusion into frequencies normally used by other digimodes. This "feature" alone very clearly states, at least to me, that FT8 DXpedition mode shall be used only in exceptional case. If this mode will be limited to the really big dx-peditions to the rarest DXCC entities remains to be seen, but it should clearly not be used in your average IOTA-expedition to some Caribbean DXCC entity, activated every year, or a QSO party, field day, SOTA, NPOTA, 13 States, or any other proposal for use in regular, repeated activities. And certainly not for contests, blatantly breaching the contest rule of not more than one signal on any band at any time.

73 de Frode LA6VQ

 

I saw a spot last night that TY7C was using the DX-pedition mode, so I downloaded the new release and read how to use it. It took me about 20 minutes to get in log on 80M FT8, from the time I saw the spot.

Zak W1VT