Yaesu DR-1X Fusion Repeater Project with a Pi 3 and RA-40 Control Interface Board

Pannel Front

The Yaesu DR-1X is a solid repeater system. Used for FM mode it is a bit lacking in control features, not even providing a courtesy tone.

In order to interface with the Echo Link system over the Internet, and also to use special features with DTMF tone selection, an external controller must be added.
The RA-40 interface board was chosen and a Pi /3 computer as a best cost effective method, with a feature rich package already available.

Software Comments

Allstar [Asterisk] software was installed on the PI 3. It was discovered to be the most advanced package, and user friendly.
Within it is the correct control package to operate the PTT function through the RA-40 control board interface on pin 13.
The package offers Echolink, and Allstar directly with a Linux OS from one download for the PI 2/3  [4 GB micro SD]

See references section below, for the software downloads.

I also have a Linux guru KL4EL to assist manipulating the PI software package which was originally a system that ran a telephone PBX, as I understand.
I then run backups of the micro SD cards using a windows 10 machine with Win32DiskImager. 
You can use larger micro SD's, and I started out using 8 GB then moved to 32 GB, but as it turns out this only makes my backups much larger and takes longer to copy them.

Engineering Section - Hardware and Cabling

Flow Diagram

RA-40  Repeater Control Interface Board


Green   HB = Heartbeat indicates PI/3 is talking to the RA-40 control board
Blue      Com OK =  Heartbeat Timer Pi is Up
Red      PTT = Push to Talk indicates Repeater is transmitting

Voice Level = Left audio channel USB => Transmit audio to Repeater from Pi/3
Mic Level = Audio input to USB <= Receive Audio from Repeater to Pi/3

Option Pins
JU1    Local / Remote Mode Polarity    Hi  = Remote mode [set to B] after doing RA-40 modification [green boards only].
JU2    5v to 12v Audio Power amp Selection      Set to 12v [set to B]

[See References Section below for ordering this board]

RA-40 Audio Level Adjustments

RA-40  Circuit Diagram [with DR-1X modification shown]

Circuit Mod

It was discovered that if the Pi/3 and RA-40 loose power, the system does not release back to local control.
The DR-1X local control lead needs to see an opened circuit, rather then 5v, or ground when the DC power goes to zero.

One 2n2222 transistor and one 4.7k resistor were added for an "opened collector" circuit. JU1 was set to B because the signal on pin 7 is now inverted.
When the power is removed from the Pi/3, the repeater goes back into local mode, dropping out of remote mode, and continues to work, without the courtesy tones or other features the controller adds.
Also when the Pi is rebooted or locks up the repeater will maintain local mode until the Pi/3 comes up and the blue Com OK light goes to "steady on" after which it will switch to remote mode.
Whenever the blue light is out, indicating the USB port is down, the repeater switches back to local mode.

The added transistor will have 3.4 vdc on the collector from the repeater pin 1, and will have to sink 68 micro amps to pull the lead low.
The 2n2222 transistor will switch with base resistor values between 1k and 1 meg.
A BC547A transistor can also be used as in the photos below and resistors in that range. A 2.2k was used in the first mod.

I have had the modified circuit in service now for several days, and it appears to be working fine.
When I switch off the power to the Pi, local mode is instant. After the Pi reboots it switches back instantly also. [1 - 21 - 2018]
A new board that will be red in color is being designed to add this modification.

Modification Details

RA-40 bottom view

The foil on pin 7 is etched opened near the 9 pin connector.
Note the two small foil holes on either side of pin 8. Watch for solder bridges when the transistor is soldered to pins 7 and 8.

Both holes are ground, so if pin 7 is bridged the repeater will not switch modes.


Emitter is bent outwards and shortened to keep the transistor close to the bottom side of the board, then soldered to pin 8.
Collector is bent the opposite way outwards and soldered to pin 7 of the 9 pin connector foils.
The 2.2k resistor is stuck through the hole and soldered, then bent over to meet the base of the BC547 transistor and soldered in mid air.
The ends are then clipped off.
Because I mounted the board on standoffs, there is enough clearance under the board to keep the transistor up off the shelf.


This modification of the RA-40 board resolves a long standing problem with reliability and I am glad we took the time to come up with this solution.
AL5X  7-19-2018

Custom Cable  9 pin Dsub on RA-40 to HD15 pin Control Port on DR-1X Repeater

This cable uses 8 conductor shielded wire. One each 9 pin D-sub male and one each HD15 male 15 pin 3 row VGA style D-sub.
The same enclosure hoods are used for both connectors.

Cable Parts Photo

I opted for the solder tail connectors.

Final Cable Pinout

Note: The shield should be connected to pin 10 on the HD15 repeater port side and left opened on the RA-40  9pin side. I accomplished this with a solder joint of all three wires above the connector but inside the hood. Pins 10,11,and shield.
Note:  For Remote / Local switching to work properly, see the modification above on the RA-40 circuit.

Note: It was discovered that pin 5 on the DR-1X was not connected inside the repeater and could not be used as the ground on the cable to the RA-40 board pin 10 had to be used.
Note: Pin 11 is also grounded on the repeater controller port to force the repeater into Analog FM mode when the controller goes active.

DR-1X Repeater Pinout

Pinnout Definitions

Control Modes

Pannel Rear

The ACC jack is used only for firmware upgrades. All remote control functions are done through the 15 pin Control I/O Port.

Cabinet Photos

CAbinet Views

DC Power Distribution and Battery Backup


The DC power distribution panel was custom made to handle a standby battery box with low voltage cutoff, a DC power supply, and some control switches, including the 2 Pi/3's and the internal light LED strips for working inside the cabinet.

Original Design Print

Shelf Layout Print

Note the Sealed Automotive Fuses used inside the insulated automotive battery box as a safety feature. Nothing worse then shorting out battery leads with no protection.
Then right up front on the panel is a battery disconnect switch / breaker between the rectifier and the battery, then finally the load disconnect breaker switch protecting the low voltage cut off unit.
The cabinet should never draw over 25 amps total, with both repeaters transmitting and all the other loads turned on.


RA-40  Supplier

Masters Communication Site   by Kevin Custer W3KKC

[I do not recommend the cables they recommend for the DR-1X repeater, as they strap the DR-1X permanently into remote mode.
To switch back to local mode you must pull the control cable off the back of the repeater.
With the RA-40 modification detailed in this document above you can simply turn the power off to the Pi.]

Pi 2/3 Software

Asterisk Allstar Software Site  For the Raspberry Pi 2/3

They recommend at least a 4 G byte micro SD chip for the Pi. We have been using both 8 and 32 Gig chips successfully in our Pi /3's.
Once loaded they can only be copied to identical size chips, if you want backups of the software for each repeater.
If I did it again I would use all 8 Gig chips, they are cheaper and still lots of extra room.
You may spend some hours setting up each repeater build, so this is an important consideration.

Software will require obtaining an Allstar node number and an account. Normally the Trustee of the repeaters by the club will have to do this one.
Numbers below 2000 can be used locally, over 2000 will be assigned by the world wide area network group when you establish your account.
If you operate two repeaters on the same local Internet box subnet, you can assign the second one yourself below 2000, and they can be linked together via the local network,
however only one will be accessible from outside if your Router only has one IP address on the Internet.

Echolink will also require a unique node number be assigned  in your software, granted by the Echolink account process.
Both will require a valid Repeater Call Sign with the FCC, and there is a waiting time involved after account setup.
You must first obtain the Allstar node number to bring up the software, before Echolink can be activated using it's node number.

Pi / 3 programming was done by Todd Dokey KL4EL

Software Support


Yaesu DR-1X

Yaesu DR-1X

Note this document is only for the DR-1X, the DR-2X does not have the same control port.

Document preparation and site Admin - David Lowrance AL5X

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