Friday, July 21, 2017

New weak signal mode FT8

Although it sounds disturbingly like a new rig from Yaesu, FT8 is actually a weak signal QSO mode from K1JT, Joe Taylor, and the folks who gave us WSPR and other modes. The mode is Franke-Taylor design, 8-FSK modulation.

I've just had my first contact with Steve VK6IR who is located right across this wide brown land.


I saw his CQ, received at -4dB, double clicked the line and the rest of the QSO, including signal reports each way, was automated.

Unlike WSPR where each over takes two minutes, the cycle time in FT8 is just 15 seconds so it feels a lot more like you're actually having some sort of conversation.

This new mode is in the latest builds of WSJT-X, version 1.8.0-rc1 in my case.

The release notes describe FT8 as follows:

"New mode called FT8: sensitivity down to -20 dB on the AWGN channel; QSOs 4 times faster than JT65 or JT9; auto-sequencing includes an option to respond automatically to first decoded reply to your CQ."

AWGN is Additive white Gaussian noise, obviously.

I kind of wish this was all a little bit more manual and that I could have a few more characters to personalise the QSO. Maybe we need a Twitter like digital mode?

1 comment:

Murray Greenman said...

Peter,
We have just the mode you were asking for. It's called FSQCall. It sends free-form text, just like sending a text message, and goes at 40 WPM. It has similar sensitivity to FT8, achieving it without requiring error correction, so is fast and slick.

FSQCall also has automated features such as selective calling, file and image transmission and signal reports. You can have real conversations with real people, ask about their family, their equipment and the weather!

See http://www.qsl.net/zl1bpu/MFSK/FSQweb.htm for more information.

73,
Murray ZL1BPU