Yaesu System Fusion, KD8CSE Presented

Report
System Fusion by Yaesu
Roger Reini, KD8CSE
Overview

Digital communications in amateur radio and the case for C4FM

Yaesu’s implementation of C4FM: System Fusion
History of Digital Modes in Land Mobile

1980’s: first digital LMR radios appear, using GMSK (GFSK) technique

Now, GMSK is out of favor, and C4FM (4-level Frequency Shift Keying) is
dominant

2003: first GMSK transceiver released for amateur radio market

2004: Icom’s D-STAR released; it also uses GMSK

2011: Motorola LMR’s Digital Mobile Radio released, using C4FM; DMRMARC demonstrated it for Amateur Radio at Dayton
Types of Digital Communication Systems

Modulation: GMSK, π/4 DPQSK, C4DM (4-level FSK)

Communication type: FDMA (Frequency Domain Multiple Access), TDMA
(Time Domain Multiple Access)

Protocol
GMSK

Simple, used in earlier cell phone
systems

Performance exceeded by other
systems

D-STAR uses GMSK
π/4 DPQSK (4-minute pi DPQSK)

High-grade modulation method,
produces low distortion

Requires linearity (like SSB
transceivers) and complicated
circuitry to implement

Not commonly used in LMR
C4FM Modulation

At same bandwidth, C4FM circuit
can be simplified and the Bit Error
Rate approved

Main modulation method in LMR
these days

Yaesu using this as the basis for
SystemFusion in the amateur market
FDMA vs TDMA

FDMA circuitry is simpler than TDMA

TDMA reduces transmission time by one-half or more, reducing power
consumption
Is C4FM compatible with D-STAR?

No, it’s not; different modulation techniques (GMSK vs C4FM)

Is this a problem in the amateur radio world?

Not really; an example of the experimentation that amateur radio is known
for
Is C4FM Digital always the superior mode?

No, it isn’t; there will be instances when analog is superior

We amateurs know that different modes have different advantages and that
some are preferred in certain circumstances

C4FM is another mode available to amateurs, increasing our capabilities; it’s
another tool in our toolbox
Yaesu’s implementation: System Fusion

Three C4FM modes, using 12.5 kHz bandwidth:

V/D Mode – Voice/Data simultaneous communication, half for voice, half for
data and error correction

Voice FR (full rate) Mode – all bandwidth used for voice, top audio quality

Data FR Mode – all bandwidth used for data

Analog FM – 25 kHz; used when signals too weak for digital
AMS (Automatic Mode Select)

Transceiver recognizes the incoming mode (C4FM digital or analog FM) and
switches over to match that mode

No need to remember to manually switch the mode on the transceiver

Enables mixed-mode communication on compatible repeaters

If a SystemFusion repeater is installed, you’re not locked out if you don’t
have a SystemFusion transceiver
New Functions Gained with C4FM

Digital GM (Group Monitor) Function – see where group members are
located

Snapshot Function – transmit images taken with camera microphone

Smart Navigation Functions

Simultaneous Voice and Data transmissions allows APRS-type position data to be
sent while transmitting

Backtrack navigation – allows one to return to a preset point (useful for hiking)
Equipment that is C4FM capable

Repeater DR-1 144/430 dual band C4FM/FM repeater

HT FT1DR 144/430 dual band C4FM/FM 5W transceiver

Mobile FTM-400DR 144/430 dual band C4FM/FM 50W transceiver
For More Information

Yaesu – www.yaesu.com; link to System Fusion page

FT1DR 2m/70cm HT

FTM-400DR 2m/70cm mobile

DR-1X digital 2m/70cm repeater

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