FT8, or: why Windows time syncing sucks!
Now: as we've all established that I'm a geek through-and-through, of course the idea of digital modes on HF caught my attention! So, I decided to give the 'ol "digital-mode-du-jour" a try, which happens to be FT8 (via WSJT-X):
A little description of FT8 (which would have helped me when I started with it):
FT8 is a "weak signal mode" that is really good at getting a QSO through even when a signal is down in the mud (ie: below the perceivable noise floor). So, even if you'd struggle to hear something on SSB voice, FT8 still may work.
What FT8 is:
In Linux, syncing your system clock to an NTP server is extremely easy! From the console, type "sudo ntpdate {NTP_SERVER_HERE}" (with time servers such as pool.ntp.org ). There: done. You can verify it by going to https://time.is
Now that I have my coffee, I'm ready to watch radar.
I went over to TARC on Saturday, and in 3 hours got 33 QSOs on FT8 on 40m, including 2 from Cuba! Here's a pic of a completed QSO with AB3WF (right-side window):
A little description of FT8 (which would have helped me when I started with it):
FT8 is a "weak signal mode" that is really good at getting a QSO through even when a signal is down in the mud (ie: below the perceivable noise floor). So, even if you'd struggle to hear something on SSB voice, FT8 still may work.
What FT8 is:
- A good mode for large signal-to-noise ratios (ie: noisy/hard-to-work environments)
- A great mode for stacking-and-racking large numbers of QSOs
- Kinda like a video game, in that your timing in responding to a CQ has to be good!
- A mode for ragchewing: it's just not built-in to the software
- A mode for when you can't get your computer's time to sync properly (more on this later!)
With all that being said: FT8 is damned fun when you start making QSOs.
Warning: If you cannot get your computer's clock to sync within 0.5 seconds of a recognized time server (ie: an atomic clock), YOU WILL LIKELY NOT BE ABLE TO MAKE QSOs!
Let me re-iterate that point: FT8 is extremely time-slot (and accurate time) dependent. This means that everyone using FT8 needs to sync to a standard time server in order for QSOs to go through.
To explain this, let me first explain how FT8 works:
FT8 is split-up into 4 15-second time-slots (TS) per minute: slot 0 (0:00 through 0:14), slot 1 (0:15 through 0:29), slot 2 (0:30 through 0:44), and slot 3 (0:45 through 0:59). Depending on how you have your WSJT-X software set, you're either going to transmit in the odd TSs (default), or the even TSs. For example: say station 1 is "FT8AB" in grid AB12, and station 2 is "FT8XZ" in grid XZ89. A standard QSO goes like this (starting the count at TS0, with explanations in square-brackets):
To explain this, let me first explain how FT8 works:
FT8 is split-up into 4 15-second time-slots (TS) per minute: slot 0 (0:00 through 0:14), slot 1 (0:15 through 0:29), slot 2 (0:30 through 0:44), and slot 3 (0:45 through 0:59). Depending on how you have your WSJT-X software set, you're either going to transmit in the odd TSs (default), or the even TSs. For example: say station 1 is "FT8AB" in grid AB12, and station 2 is "FT8XZ" in grid XZ89. A standard QSO goes like this (starting the count at TS0, with explanations in square-brackets):
TS0: CQ FT8AB AB12 [calling CQ with their callsign and grid square]
TS1: FT8AB FT8XZ XZ89 [responding to CQ with their callsign and grid square]
TS2: FT8XZ FT8AB R-05 [reply w/ signal read: -05 is in db below noise floor. bigger = better]
TS3: FT8AB FT8XZ R-12 [reply w/ their signal read]
TS4: FT8XZ FT8AB RRR [reply with "RogerRogerRoger", an acknowledgement]
TS5: FT8AB FT8XZ 73 [standard 73 (ie: "best regards" message)]
TS6: FT8XZ FT8AB 73 [standard 73 message]
So, the above happens over a minute and 45 seconds, barring any dropped transmissions. If "auto-sequence" is enabled, WSJT-X is really good at formatting and replying with the appropriate messages.
Now: a typical FT8 transmission takes close to all 15 seconds to transmit the encoded data (12.6 seconds, to be exact). Thus: if your computer's clock is off by a second or two, the receiver will not get your entire transmission and WSJT-X will discard it.
In Linux, syncing your system clock to an NTP server is extremely easy! From the console, type "sudo ntpdate {NTP_SERVER_HERE}" (with time servers such as pool.ntp.org ). There: done. You can verify it by going to https://time.is
Now, in Windows: this is not very easy. The guys over at Microsoft decided to not make the ntp infrastructure in Windows 10 (or server-side at time.microsoft.com) very accurate. The best I could do was 1 second of drift: good enough for government work, but not for FT8. This frustrated the hell out of me, as I was seeing the FT8 traffic, but no responses to my traffic what-so-ever. This is where I definitely recommend the Meinberg NTP client for Windows: it does the job, and does it well! Once Meinberg was installed and my system clock was synced, the QSOs just started dropping on my lap!
A note: I posted about my FT8 woes on Reddit's /r/amateurradio subreddit, and they helped get me squared away (ie: FIX YO TIME, FOOL!). I highly suggest you get a Reddit account and join /r/amateurradio, as those guys are pretty awesome!
BTW: /u/robonova-1 recommended that I watch this video for setting-up my 7300 for digital modes. I did, and it worked like a charm, so you can too! I also will copy/paste my recommendation I made on my Reddit post:
If you have a 7300 and an SD card, do what I did to make things easier:
- Reset your radio to factory default, and save a copy of this setting to the SD card (named "default")
- Make your digital-mode changes, and save those to the SD card (named "digital")
- Restore to "default" settings
- Make your analog (ssb/am/etc) changes, and save those to the SD card (named "analog")
- Now, you can easily move the radio from "digital-optimized" to "analog-optimized" with a few button presses.
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Now that I have my coffee, I'm ready to watch radar.
I went over to TARC on Saturday, and in 3 hours got 33 QSOs on FT8 on 40m, including 2 from Cuba! Here's a pic of a completed QSO with AB3WF (right-side window):
But I wasn't really hammering it too hard: this was also talking to the other guys in the shack at the time. If I had my own shack and tower, I bet I could get 25 QSOs/hour. But in one day at TARC, I got my first 16 states towards Working All States.
Now, let me talk for a second about the awesomeness that is PSKReporter! If you're using a digital mode, you need to use PSKReporter. Basically, it works like this:
- Hams using WSJT-X (or other PSKReporter-capable programs) see your callsign in their traffic (the left window), and report this (along with their callsign and gridsquare) to PSKReporter.
- You go to PSKReporter, and enter your callsign (and mode/band if you want)
- You see where your signal is being heard at, in real-time.
This is an infinitely-awesome tool for seeing how well your signal is getting out! Below is PSKReporter showing how my signal was doing at 30 watts when I was working at TARC on their 40m beam pointed northward:
All of the blue dots are stations reporting to PSKReporter. The blue dots with a time showing are ones that have heard my callsign and when they last heard it. So, PSKReporter is a great way to show how your signal is getting out! But, it only works well if everyone participates!
So: inside of WSJT-X's settings, click on the "Reporting" tab, and click "Enable PSK Reporter Spotting". There, done. Wasn't that easy?
So: inside of WSJT-X's settings, click on the "Reporting" tab, and click "Enable PSK Reporter Spotting". There, done. Wasn't that easy?
Ok: Maybe video to come showing me working the mode. Maybe.
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