Automated Digimodes
Weak Signal Propagation Reporter
A few years ago, Nobel prize winning physicist
Joe Taylor created a new protocol and wrote some software that would do this.
Essentially, you run his software, and at a specific time, it transmits your callsign, location, and power.
Other people running the software decode your signal, and report it to a central
website. This was a great improvement on the old beacon system. For a start, there were thousands of these
beacons, rather than the ten or twenty that there are on the old system. Additionally, your computer took care
of decoding the signal, and calculating the strength of the signal and the distance between you and the
transmitter.
You can see a live visual representation of the WSPR reports received in
IO81.
It used good Forward Error Correction, and it worked very well.
However, it has some downsides:
- It is a one-way system only
- You can't send arbitrary information - it is hardcoded.
- It takes 2 minutes to transmit a single cycle.
- You have to transmit in synchronisation with the receiver
- It requires the Internet to see where your signals have got to
These downsides meant that it couldn't be used for general-purpose communications. It was purely an automated beacon system for reporting propagation
FT-8
Joe then created another digimode called FT-8, which took elements from WSPR. It became amazingly popular. (You
can see the
last 15 minute's worth of contacts on pskreporter.info)
It shortened the transmission time down from 2 minutes to 15 seconds. It allowed arbitrary data (a small
amount), but there was a protocol for a contact:
- Hello anyone, I'm G1ABC in London
- Hello G1ABC, F2DEF in Paris
- Hello F2DEF, G1ABC here. Your signal is -12
- Hello G1ABC, F2DEF here. Thanks, your signal is -08
- Hello F2DEF, G1ABC here. Bye
- Hello G1ABC, F2DEF here. Bye
This is the format for each FT-8 contact. It's so formulated, that the software can make the whole contact for
you. Indeed, I've initiated a contact, and had to go downstairs, and when I've come back up, I've "made a
contact".
But yet I haven't learnt anything about the other person, other than their location (which I could probably have
found on qrz.com), and the signal reports (how they're receiving me, and how I received them).
This is essentially an automated signal reporting system. It's like WSPR, but faster, slightly less sensitive,
and two-way, so it technically counts as a contact.
I've racked up hundreds of contacts around the world with FT-8, but I can't say that I've remember any of them.
I don't know anything more about the person at the end of it than I did at the start, other than they exist, and
they were on-air when I was on.
If you compare this with the Olivia contacts I've made, I remember a
lot more of them. I've had real contacts with them. I know things about them, their name, what they do for a
living, do they have family, children, have they ever been to the UK, what their other hobbies are.
I can see that for some people, they just want to know that their station can reach around the world, they just
want to "collect" all the countries, much like stamps, and for them, a 2 minute contact, exchanging the bare
minimum of callsign, location and signal report qualifies.
But for me, I prefer fewer, longer, more in-depth contacts.
Now, I want to make it clear that this is fantastic technology. I'm in awe of how it can pluck out signals below the noise level, the error correction involved, etc. It's great that amateur radio has great minds like Joe Taylor who can come up with clever modes like this.
So what's the problem?
It's very dull.
It's also very popular
The real trouble is, is that so many people are using FT-8, and it's so easy to make contacts, that there aren't
many people left using the other digimodes.
After I've been calling CQ fruitlessly for 30 minutes, I fire up FT-8, and make a few quick contacts. It's easy,
it's guaranteed. And that means I'm contributing to the problem.
JS8CALL
There have been attempts to take the clever technology used in FT-8, and make it a more conversational mode. JS8CALL is one of these. JS8 on pskreporter.info
I think a lot of FT-8's success is down to how easy it is. The software does everything. It sets your radio to the right frequency. It starts monitoring, displaying the people transmitting, asking for contacts. And with one double-click, it initiates and completes the entire contact for you in about 90 seconds.
The alternative?
The alternative for me is what I'm calling interactive digimodes