1. FT8 “Taking Amateur Radio By Storm!”
By: Jonathan Kayne, KM4CFT

2. So, what is FT8?
FT8 is a weak signal mode that is a variant of JT-65, with the added benefit of having a significantly shorter transmission time.
Developed by Joe Taylor, K1JT and Steven Franke, K9AN
Will get to more info on JT-65 in a little bit

3. Joe Taylor, K1JT
Joe Taylor is a professor at Princeton University, and obtained the Nobel Prize in Physics back in for his work in pulsars.
Significant research in Moon-bounce (EME)
WSJT (Weak Signal Joe Taylor)
WSPR (Weak Signal Propagation Reporter, pronounced “Whisper”)
FSK441, JT-65, JT-9, FT8
- WSPR is a method used for analyzing propagation, and essentially allows a server to control your rig and by using a network of stations, you can see the effects that prop. has on an area.
Similar to PSKreporter or Reverse Beacon Network.
FSK441 uses multi-frequency shift keying.

4. Basics of a digital mode
Digital modes are simply using a digital interface to carry out a communication.
Most Basic: simple binary values:
FSK (Frequency Shift Keying) – Radioteletype/RTTY
PSK (Phase Shift Keying) – PSK31
Texting using ham radio
FSK – alternating between two frequencies, each representing a zero or one
PSK – alternating between the sine and cosine wave

5. How to use a digital Mode
You simply need to interface a computer with your radio
It is incredibly easy to set up
Audio feed (PC speaker to Radio Mic, PC Mic to Radio speaker)
A way to key up the radio
Software: Fldigi, WSJT-X, HRD, etc.
- Duck tape a speaker to your hand microphone…

6. JT-65 Weak signal mode, QRP Designed for moon bounce
Can detect signal well below the noise floor
Time dependent
~46s Transmit time
65 tone MFSK
Adds redundancy to create Forward error correction
Reed-Solomon encoding (often used in DVDs)

7. Typical JT-65 or FT8 QSO

8. Disadvantages of JT-65
As you can see there are about 7 cycles per QSO, so a single QSO can take up to 7 minutes!
Not very good for contesting or if you want to make a lot of QSO’s in a given time period
Meant for basic QSOs, not for “ragchewing” (disadvantage of FT8 too)

9. FT8
FT8 fixes the problem that JT-65 has by shortening the time period to 13 seconds!
This means you can complete a QSO in ~1.5 minutes!
It is for this reason that it has become incredibly popular
75 bits of data
Uses LDPC (low density parity check) for encoding
8 tones, 6.25 Hz spacing
3 7x7 costas Arrays (start, middle, end)

10. Statistics from PSKreporter
It has become so popular that some hams actually think that it is “destroying” ham radio.
Hams said this about AM…then SSB…then FM…then RTTY…then PSK31…then [I’m gonna stop while I’m ahead!]

11. Using FT8 Requires a properly synced time clock Show the layout
Auto-sequence – you have about 3 seconds to respond

12. FT8CALL
A community based mode based off of FT8
More of a ragchew mode

13. Thanks!
Jonathan Kayne
KM4CFT