Going digital with the FT-70D

Posted by Fred C. (W6BSD) on Jul 17 2019

The FT-70D is a great little radio that I always recommend for new hams as well as for experienced hams who want to try digital voice. It is simple to use and well priced for the quality and performance you get.

What is digital

Yaesu FT-70D

There are several forms of digital communications in the ham radio world. From CW1 to digital voice such as DMR or C4FM2. Here we are going to focus on the C4FM digital mode found on Yaesu radios.

In digital mode, the analog audio signal coming from the microphone is digitized, compressed and transformed into a stream of ones and zeros. Then, that digital stream is transmitted on the airwaves. On the receiver side, the series of ones and zeros are transformed back into analog before being sent to the speaker.

Yaesu uses the C4FM protocol but other digital modes such as DMR or D-Star are also available. The high-end Yaesu radios, such as the FT-2D or FT-3D, are easy to use with a big screen and self-explanatory options. On the low-end side, the FT-70D is capable of doing the same things as the more expensive radios but it is all done through sequences of keys.

Forms of digital communications.

There are several ways to communicate digitally with your radio. The simplest form is from radio to radio, without using a repeater. This is called simplex communication. You can also extend the range of your radio using a local repeater or a hotspot. A hotspot is a tiny personal "repeater" connected to the internet, using just a few milliwatts.

Simplex digital

Two or more hams talking to each other directly. On a C4FM radio, you don't have anything to do. Just choose a simplex frequency, press the PTT button and talk.

FT-70D AMS selected

If you haven't changed any of your radio’s settings, the TX Auto mode should be selected. The radio will automatically start the QSO using digital if the person on the other end is C4FM capable. If your correspondent is equipped with a regular FM radio, your radio will automatically fall back into FM mode.

To make sure the Automatic mode is selected, the word AMS3 should be displayed under the frequency on the radio screen. If not, press the AMS button on the lower left side of your keypad for 3 seconds, until the word AMS appears on the screen.

You can select which mode you want to use with a short press on the AMS button, then use the dial knob4 on top of your radio to select which mode you want to work with: Digital or FM.

The right LED on the top of your radio will light up blue when you are transmitting or receiving in digital and light up red when your transmission is in FM.

Repeater and hotspot

Before you can work on a repeater or a hotspot you need to enter your callsign in your radio settings. You can also enter your name. The first time you turned on your radio, it should have asked for that information. If you haven't set your call, or if you want to change it, go to settings, option 64 MYCALL. Enter your name after your call sign separated slash character /. For example, mine is W6BSD/FRED. This call/name will be automatically sent over the air. The person you talk to will see your call/name on their display.

Unlike DMR, you don't have to program your radio to have a digital conversation through a repeater. On a C4FM radio just dial the frequency of your digital repeater. The offset should be set automatically. Then set the squelch tone. That's all you have to do. You can then have your first digital contact.

On the FT-70D to set the squelch tone press the key F key then 5 - SQTYP to select the type of squelch used by the repeater. Then press F then 6 - CODE to set the tone frequency or code.

Chatrooms

Most C4FM repeaters, but not all, are connected to the internet. The ones that are connected allow you to dial into a chatroom5. A chatroom is a place where several repeaters around the world can be connected. Any conversation going on in that room is transmitted to all the connected repeaters. To have access to that feature you need to connect your radio to the repeater, then connect the repeater to the chatroom of your choice.

The X key is for Wires-X

When I say connect the radio to the repeater, this means putting the radio in control mode of the repeater. The radio is then able to send commands using digital mode to remotely control the repeater or the hotspot. For example: To connect to a chatroom, or disconnect from a chat room.

To connect to a repeater, high-end radios have a button labeled X, either on the keyboard or on the touch screen. On the FT-70D this key doesn't exist. This feature is turned on by a short press on the function F key followed by a short press on the AMS key. The blue LED should blink a couple of times. This signifies a digital transmission is occurring. Then, the word WIRES blinking is displayed on your screen for a few seconds, followed by the word CONNECT for a few seconds to signify you that your radio is connected to the repeater. Once the radio has joined the repeater, the name of the room the repeater is already connected to will be displayed on the radio screen. The repeater is now ready to receive your commands.

Wires blinking

Connection established

Input screen

To connect to a room turn the dial knob, until you see the screen with an En and a star * followed by dashes. Using the radio's keypad, enter the number of the room you want to connect to, then press the AMS key to send your command.

You can find the room numbers on the Yaesu Wires-X active rooms.

For example, to connect to the American-Link network, once you are "connected" to the repeater, turn the dial knob button until the screen En appears, enter the room id 21080 and press AMS. The blue light indicating that your radio is transmitting in digital will blink a couple of times, then the word connects, followed by the name of the room, should appear on your screen. You are now connected to America-Link.

You can also disconnect the repeater from a room using the BAND key, on the top right corner of your keypad. Once your radio is "connected" to the repeater, turn the dial knob until you see Cn6 followed by the name of the room on your display. A long press (3 seconds) on the BAND key will disconnect the repeater from the room.

I am using the word connection a lot in that article. I realize it might be a little confusing since several things are connecting. I hope the next drawing will help you understand what all these connections are about.

There is a connection from the radio to the repeater, then a connection from the repeater to the room.

What is connected where.

I hope this will clarify all the connections I mentioned.

FT-70D Commands

Here is the list of the commands used to connect and disconnect.

Key Function
F AMS Connect your radio to the repeater
MODE long press disconnect your radio from the repeater
BAND long press disconnect the repeater from the chatroom
AMS Enter or Send

All the commands described here work on a repeater and the majority of hotspots.

Beware of ongoing traffic

Before connecting or disconnecting a repeater from a chatroom, you should make sure you are not disconnecting while someone else had an ongoing QSO. Introduce yourself and ask if you can use the repeater. Disconnecting a repeater from a room in the middle of a QSO will be seen as rude.

Yaesu Fusion networks

With C4FM you can have access to several Fusion networks. One of the Fusion networks you might have heard of when buying, or reading the owners manual of your radio is Wires-X. There are other Fusion networks your radio can access.

Wires-X

Wires-X is the network developed and managed by Yaesu. This is what Yaesu repeaters usually connect to. This network is closed. This means the software and the protocol are not open-source or even published. Other networks cannot easily connect into Wires-X. Only Yaesu radios, software, and repeaters can connect to the Wires-X.

Ham radio operators are full of inventiveness and resourcefulness. They have created gateways between Wires-X and the rest of the world. Unfortunately, these gateways are far from perfect. The audio quality is degraded, and some of the features found on Wires-X networks are also missing.

Hotspot

Hotspots are just tiny repeaters connected to the internet. Ham radio operators install them in their homes, or their cars for mobile operation. Hotspots transmit power is around 100 or 200 milliwatts. This is plenty enough to operate from inside the house or in the backyard.

MMDVM Hotspot on a Pi Zero

If you search on the internet for MMDVM hotspot you will find a lot of offers. Their prices go from less than $50 for a kit to more than $300 for a hotspot pre-setup by the seller.

These hotspots are packed with interesting features. They allow you to connect to the YSF network or the FCS network. Unlike Wires-X these 2 networks are open-source and developed by ham radio operators like you and me. Hotspots cannot connect to Wires-X chatrooms directly for the reason I have described in the previous paragraph. But some of the YSF or FCS rooms have gateways to Wires-X rooms.

For example, America-Link (id #21080) on a Wires-X is also accessible from YSF with the (id #89804). These two rooms are linked together using a gateway.

These hotspots are also capable of doing cross mode repeat for certain modes. With a C4FM/Yaesu radio, you can connect to a DMR, P25, or NXDN networks, and have a QSO with a person using a completely different radio or system.

This blog post is not intended to replace the manual that came with your radio. The digital world is packed with interesting features. My best advice would be to read your radio's manual and some articles found on the internet. This will help you discover all the capabilities of these digital modes. The purpose of this post is to scratch the surface of the digital world to introduce you to the capabilities these small handheld radios have to offer.

If you want to chat with me about digital modes, ask me questions or just ragchew, you are welcome to join me on my chatroom BAYAREA-YSF id #00043.


  1. Yes, CW is considered to be the first digital mode 

  2. C4FM is a 4-level FSK Technology to transmit digital voice and data over the Amateur radio bands 

  3. Automatic Mode Select 

  4. DIAL Knob is the knob on top of your radio. 

  5. Chatrooms are called Talk Groups on DMR 

  6. Cn is for Connect 

Tags:  C4FM    Digital Radio


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