DV-MEGA Raspberry Pi Radio... and other stuff!

I have been somewhat amiss these last few months.  I've neglected to blog about the work of Guus van Dooren PE1PLM in The Netherlands.

Guus has been very busy working on various kinds of D-Star compatible hardware and supporting firmware for quite some time.

Here is a quick tour of what Guus has been up to!


DV-MEGA Dual Band Radio

The Dual-band Arduino shield has two Analog Devices AD7021 GMSK RF transceivers on board and plugs into an Arduino.  The Arduino then is loaded with firmware and is plugged into a computer via USB.  The G4KLX D-Star Repeater software directly supports this combination.



DV-MEGA GMSK DV Node Adapter

The GMSK Node Arduino shield once again plugs into an Arduino and the allows you to use an external N-FM transceiver to put together a higher powered D-Star Hot Spot... or with two radios a full repeater. As before the G4KLX software supports this hardware combination. 

Below is a 3D rendering of the GMSK Node shield.


DV-MEGA AMBE3000 Shield

The upcoming AMBE Shield is another Arduino accessory.  It has an onboard AMBE3000 vocoder chip and will be able to be used to directly encode/decode D-Star (and other?) digital audio.  Unlike the NW Digital Radio AMBE3000 board, the DV-MEGA board has connections for microphone/PTT and audio out.


DV-MEGA Raspberry Pi Radio

This is one DV-MEGA product I have had direct, personal experience with.  I ordered one and received it mid June 2014!  The Raspberry Pi Radio uses an Analog Devices AD7021 transceiver chip and plugs directly onto the Raspberry Pi GPIO connector.  As with other DV-MEGA products, the Raspberry Pi Radio is fully supported in the G4KLX D-Star Repeater software.

After some inital teething issues with getting the G4KLX software configuration right, the DV-MEGA Raspberry Pi Radio has performed perfectly.  I still have to modify the Raspberry Pi case I use in my Portable D-Star HotSpot to allow for the R-Pi Radio SMA connector and ATMEL micro.

I bought it to turn my Portable D-Star HotSpot into a dual band system!  I now have a "C" module (2m DVAP) and a "B" module (Raspberry Pi Radio).

I've uploaded some photos of my Raspberry Pi Radio here!



My DV3000 AMBE board has arrived!

Well, that was quick!

I was able to get an order in for one of the first batch of NW Digital Radio DV3000 boards... and it arrived on June 3rd!  First shown to amateurs at the 2014 Dayton Hamvention, an initial run of one hundred DV3000 boards were made.

I had already installed the latest G4KLX Dummy Repeater software on my office PC (with support for the DV3000 as well as the DV Dongle) so all I needed to do was setup a Raspberry Pi with the DV3000.

I followed this excellent document written by Jonathan Naylor G4KLX and John Hays K7VE.

Creating an AMBEserver

The first section of the document details how to prepare the Raspberry Pi for the DV3000. This consists of (a) increasing the clock to the Raspberry Pi UART, (b) disabling the getty (to allow terminal login) running on the Raspberry Pi serial port, and then (c) disable the console on the serial port.

You are then able to power down the Raspberry Pi and fit the DV3000 to the Raspberry Pi GPIO connector.

Then is the process of updating the Raspberry Pi operating system, installing required software libraries including downloading and building wiringPi.

Next you copy over the latest G4KLX AMBE Tools source code from the ircDDB Gateway Yahoo Group and then build the dv3000d AMBE Server daemon.

The resulting dv3000d executable can then be moved to a convenient location and started with sudo ./dv3000d.

sudo ./dv3000d -d will return control back to the console and leave dv3000d running in the background.

Once the AMBE Server is up and running, you can "point" the G4KLX Dummy Repeater or AMBE Tools software at the DV3000 equipped Raspberry Pi.  It's a great alternative to the DV Dongle.

My only (little) issue with the DV3000 board is that it sits a little high.  This is due to the piggy back connector arrangement that allows other expansion boards to be plugged into the Raspberry Pi/DV3000 combo.  My DV3000 equipped Raspberry Pi won't fit into any of my cases!  I am contemplating unsoldering the piggy back connector and fitting a lower profile one so I can fit it into my cases.  I don't really need the ability to plug another board into the top of the DV3000. 


If you have an early release Raspberry Pi board without the two mounting holes you will need to be careful with the 1/2" threaded spacer to ensure it doesn't short out to the Raspberry Pi PCB.  It may pay to remove it if you have one of these earlier Raspberry Pi boards.

In short... I am VERY impressed with the DV3000 board. It works well, the build quality is excellent and the inital software support ensures you can have fun with it immediately.

I've uploaded some photos of my DV3000 in the photo gallery.





DV3000 AMBE board from NW Digitial Radio

NW Digital Radio has announced a plug-in AMBE3000 board for the upcoming UDRX-440 transceiver and Raspberry Pi computer!  Both of these amazing devices share a compatible GPIO connector.


• DVSI AMBE3000 Chip
• 26 Pin Stackable Header compatible with UDRX and Raspberry Pi
• UART Packet Interface 230.4 kbaud
• Expansion Port w 4 GPIO
• Serial Test Software included

Open Source Applications:

• ircddbgateway/repeater
• dvtool file converter
• Bi-directional analog to AMBE
• UDRX Support for D-STAR DV

AMBE Vocoder For:

• DMR (DMR operation may require licencing from Motorola)
• dPMR
• Yaesu Fusion

The DV3000 adds D-STAR DV capability to UDRX or Raspberry Pi and is sold as a tested PCA with applications software offered by others.
The DV3000 provides a Packet UART interface at 230.4 kbaud. Audio Data is sent as 16 bits pcm at 8kHz sampling rate. The AMBE Vocoder returns a 3600 bps compressed stream with FEC (Forward Error Correction) which is muxed with 1200 bps of ancillary digital data by the D-Star protocol to produce a 4800 bps D-STAR DV stream.

By using the UART for both Audio and compressed data, the Pi’s SPI, I2C and PCM pins are available for other functions. GPIO Pins 22-25 are routed to pads for uses such as PTT or COR (external signal conditioning may be necessary).


I already have an UDRX-440 transceiver on pre-order and am seriously thinking about purchasing the DV3000 AMBE board as well.  Being compatible with the Raspberry Pi make this board a great tool for the home-brew D-Star experimenter.  The potential to decode other digital voice formats is a huge plus!




Homebrew D-Star History!

I was going through some old papers the other day, sorting out what I needed to keep and what should be thrown into the trash.

I found the envelope that Satoshi Yasuda used to send my original DV Node Adapter PCBs.  I first came across Satoshi's website in early November 2008 after finding a link on a web page maintained by Adrian VK4TUX.  There was virtually NO software to use with the DV Node Adapters back then, but I wanted to build a stand-alone D-Star repeater and the Satoshi boards could do this with the addition of a 2nd PIC.

I ordered two boards for USD$22 including postage.

The boards were sent on 3rd November 2008!

I received v01.01 boards from Satoshi.  This version had USB-A sockets instead of the more common USB-B.  I had a track down USB-A to USB-A cables to connect them to a host computer.

While I had ready access to 99% of the components I needed to build the DV Node Adapter boards, the CMX589 modem chips came from Fred van Kempen PA4YBR in The Netherlands.  He too was working on GMSK modems for use with D-Star and was able to get a good price for the modem chips in bulk.  I received two CMX589 chips from Fred in early February 2009.

Both of my original Satoshi DV Node Adapter board are still fully operational, there is one in each of my home brew D-Star repeaters!



Motorola MTR2000 D-Star Repeater

I recently received a very interesting email from Dimitris SV1EDZ in Greece.  He sent me a link to a YouTube video showing a Motorola MTR2000 based D-Star repeater he built.

This is a 40W UHF repeater.  TX 438.8375 MHz -7.6 Mhz offset.

It uses the excellent ON8JL standalone D-Star Node as the D-Star controller.  You only need to add power, internet and a radio (or repeater) to get a fully functioning D-Star HotSpot or repeater.

As with most equipment from Motorola, the MTR2000 is very well engineered and is well suited to high duty cycle repeater operation.  It it rated for 100% duty cycle at full power.

The appropriate flat audio in/out, PTT and ground connections were found on one of the expansion connectors.

Dimitris has access to a LOT of nice test equipment to set up the deviation and tune the flatpack notch duplexer.

Dimitris told me that this repeater is always connected to REF045 C.

Seeing how other amateurs around the world are building their own D-Star compatible infrastructure is very encouraging!

I've uploaded all the photos that Dimitris sent me to the photo gallery.

You can find his YouTube Channel here!