VK5REX C is operational!

Sorry for the lack of posts over the last few months. 

On the 29th January 2015, Tony VK5RF and Michael VK5ZEA drove to Whyalla (540 km round trip) to collect three duplexers from the QTH of Arne VK5NEX.   In the previous week, Matt VK5ZM had transported them from Paul VK5BX in Adelaide (390km).  Quite a journey!

One duplexer was destined for the VK5RAC 70cm FM repeater at Pillaworta Hill.  This was built from a flat-pack notch duplexer and a pair of bandpass cavities.  The notch duplexer was the one previously used at the VK5REX D-Star repeater.  This was to replace a HUGE six cavity duplexer that was too big to fit in the rack.  The new duplexer fits nicely in the 19" rack, sitting just above the 70cm repeater equipment.

The other two duplexers were for the VK5REX D-Star repeater and these were installed on the 31st January 2015.  A new 70cm duplexer to replace the temporary unit provided by Paul VK5BX.  This new duplexer uses my original 1MHz wide six-pole DCI filter, a notch cavity filter and a pair of pass cavities.  A circulator/isolator is also used on this duplexer.

The performance of this new duplexer also allowed me to permanently remove the ARR 70cm preamp from the receiver path.

The other duplexer has been a long time coming!  The 2m VK5REX C D-Star repeater finally has it's own duplexer and is now fully operational.  The home-brew 2m D-Star repeater has been operating with a hybrid two antenna setup for a while after it's installation, and for the last year or so has been off the air.  The repeaters VHF folded dipole has been used for the MarineTraffic AIS receiver

Eventually I'd like to relocate the VK5REX C antenna higher on the tower... but that will have to wait until the weather is a little more predictable.  For now I am more than happy just to have it on the air!

You can find more photos in the gallery!

Thanks to Paul VK5BX, Tony, VK5RF, Matt VK5ZM and Arne VK5NEX.




North West Digital Radio Thumb DV

A few months ago the guys at North West Digital Radio announced the development of the DV3000U or Thumb DV product.

The Thumb DV packs the same DV3000 AMBE vocoder chip found in the DV3000 Raspberry Pi/UDRx440 plug in board in a convenient USB "thumb drive" form factor.

I put my hand up for a Thumb DV and I received one from the first production run.


At the time of writing this blog post, the Thumb DV has software support via AMBEserver for Linux and AMBEserverWin for Windows based machines.  The G4KLX Dummy Repeater software can use the AMBEserver via UDP IP.

I believe direct connected USB support for the Thumb DV in the both the G4KLX Dummy Repeater and the Dutch*Star WinDV software isn't too far away.

At US$119.95 + shipping, the NWDR Thumb DV represents excellent value for money.  This product places the DVSI AMBE3000 chip in an easily deployable and convenient form factor. 

I hope the availability of the Thumb DV will prompt both hardware and software developers to create new and exciting products for amateur radio.  There is a LOT of D-Star hardware support for GMSK modems, but not a lot for other digital formats.

You can find the Thumb DV specification sheet here.




JARL D-Star Protocol Specification Ver.5.00

Today I noticed a new, updated JARL D-Star Protocol Specification document on Satoshi's web page.

It's been quite some time since the last update... Ver.4.3c was released in March 2004!

I have sent an email to JARL enquiring if an English version will be produced.  Hopefully the entire document will be translated, just scanning through and picking up on English words it seems there is a lot of interesting stuff in there.

I also sent an email to Satoshi, asking him what was new.  He replied that there is a new part defining the new data only D-Star mode where the entire 4800 bps D-Star stream is used for data (no interleaved voice/data).  This mode will make it's appearance in the soon-to-be-released 50th anniversary edition of the Icom ID-51A/E radio.

Satoshi has also confirmed that existing repeater infrastructure/gateways will be able to deal with this new data only mode.  

Seeing as the ID-31A/E, ID-5100 and IC-7100 radios have user upgradable firmware, I hope they will be able to support this new data only mode.





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.