Friday
Nov092012

My next D-Star project!

As mentioned a few blog posts back, I am planning on building a portable D-Star Hot Spot based on the amazing little Raspberry Pi computer.   I've been consistently amazed at how well the ircDDB Gateway/DVAP Node software works on the Raspberry Pi. A MikroTik Routerboard RB/751U together with a Huawei 3G USB dongle will be used for internet connectivity on the go.  

I could connect the 3G dongle directly to the Raspberry Pi (via a powered USB hub) and connect to the internet via a PPP session, but I like the flexibility that the dedicated external router provides.  I will be able to use the Routerboard internet connection for other devices, directly via Ethernet or via WiFi.  If I am in a location that has internet will be able to plug the Raspberry Pi directly into a DHCP enabled network and not have to worry about having to change the R-Pi TCP/IP configuration.  Being behind a NAT router is nice and secure too.

I am slowly gathering all the parts needed for it to come together.  On a recent trip to Adelaide I purchased a Pelican 1200 case... in Desert Tan!  I thought I might have been able to squeeze everything into the smaller 1150 case, but it would have been an engineering nightmare, especially when you need to factor the space that connectors take up.  An assortment of right-angle and up-angle Mini and Micro USB cables have been ordered via eBay that should make connections between the components easier.  A 8-36V to 5V switch mode DC-DC converter arrived today, this will power the Raspberry Pi and USB hub.  

Everything will be mounted on a small 2mm thick aluminium plate secured to the bottom of the Pelican case with 4mm metal threads bolts secured into "nutserts".  I will be using small squares of Super Velcro to keep all the individual components in place.  I may have to end up fabricating some small brackets to hold the router securely.

A Pi Bow case has been ordered for my Raspberry Pi to keep it physically safe and for mounting convenience.

At this stage my portable D-Star Hot Spot will be single band using a 2m DVAP Dongle.  The powered USB hub will allow me to add a 2nd 70cm DVAP Dongle without stressing the limited power budget available from the Raspberry Pi USB sockets.  I will be fitting two "chassis mount" F-F SMA adapters in the Pelican case on either side of the pressure relief valve for antennas.

Stay tuned for updates on this project!

 

Thursday
Nov082012

DV-RPTR V2 & enclosure and OLED display

Some pictures of the new DV-RPTR V2 board in its custom enclosure have become available on the DV-RPTR Yahoo Group.

 

The engraved front and rear panels look very nice.  One of the Mini DIN sockets on the rear is a serial port for GPS input. I originally though it might have been for a 2nd transceiver.   The inclusion of Ethernet is interesting and opens up the possibility of the DV-RPTR V2 communicating directly with D-Star reflectors and gateways on the internet without the need for a computer.

The rotary encoder can adjust receive volume and can also be pressed to access a menu.  It looks like it has a transparent shaft with LED illumination.   The small OLED screen is for user feedback and is the same display that can also be connected to the DV-RPTR V1 board.

Several version of the DV-RPTR V2 board will be available, including one with no AMBE vocoder or Ethernet capabilities.  This is ideal for those needed a basic USB connected GMSK modem for a D-Star Hot Spot or repeater where you don't need the extra hardware.

Some more photos of the DV-RPTR V2 board in it's enclosure can be found in the Photo Gallery.

Friday
Oct192012

D-Star tastes good with Raspberry Pi

I have finally installed the G4KLX D-Star ircDDB Gateway / DVAP Node software and configured it to work on my Raspberry Pi computer.

Prior to this, I have also been trying to get the G4KLX software working on my HardKernel ODROID-X board... but without much success.  I haven't given up on the ODROID-X... however it's back on the shelf at the moment.

Getting the G4KLX software working on the Raspberry Pi was quite easy.  This is mainly due to the work of a dedicated group of pioneering Raspberry Pi/D-Star enthusiasts who spent time porting the software over to run on the ARM based Raspberry Pi, thus making it easy for others to follow in their footsteps.  

Hans DL5DI has set up an repository that makes installing the G4KLX software on the Pi a painless process.

 

The ARM based Raspberry Pi runs the Debian based Raspbian Wheezy Linux distribution.  Because of how the source code was compiled, the Soft Float version of the operating system needs to be used.

I did the entire installation via a puTTY SSH session, all I needed to do was find the Raspberry Pi's IP address from my DHCP server, log in and go though the install procedure.  I plan on running the Raspberry Pi "headless", without a monitor/keyboard/mouse.  I did have some concerns that turning the Raspberry Pi off by "pulling the plug" not going through a proper shutdown would have the potential to corrupt the OS on the SDHC card... but so far it hasn't caused any issues.

The configuration of the G4KLX software can be a little confusing to people unfamiliar with it.  I have been playing around with the Windows version of the G4KLX software so most the config setup made sense to me.  Hans DL5DI has also put together a great script that leads you through each step of the configuration... thanks Hans!!

Look in here for some documentation on the G4KLX software.

Eventually I plan to build up a transportable D-Star Hot Spot with a Raspberry Pi, DVAP Dongle, Mikrotik Router, 3G USB dongle for internet connectivity and a 12V gel battery pack... all neatly mounted in a nice ready-to-go package, something like a small Pelican case.

I was thinking about using my Huawei 3G USB dongle directy on the Raspberry Pi... but have decided to use a Mikrotik RB715U 3G WiFi router so other devices can use the internet connection if needed... and I wanted to keep the configuration of the Raspberry Pi as simple as possible.

Stay tuned to the VK5REX website for updates when I start on this next project!

 

Thursday
Oct182012

DV-RPTR board.... version 2!

Some photos of the new DV-RPTR board have been posted in the DV-RPTR Yahoo Group.

It is bigger than the original DV-RPTR board, but also contains an on board AMBE vocoder and some other hardware enhancements.  

Some interesting looking RCA connectors, an RJ45 modular microphone socket, a 3.5mm socket, LED indicators and what looks like a rotary encoder are on the "user" end of the board.

There seems to be an Ethernet socket on the "back" end of the board along with (possibly two) 6 pin mini DIN socket/s for the radio connections, power in and mini USB socket.  It would be very nice if this board could connect directly to a network for "gateway" communications.

The firmware being developed for the new board will be backwards compatible with the old version, albeit with limited functionality due to hardware limitations.  This is good news for owners of the original DV-RPTR board, they will not have an orphan device on their hands.

Hopefully the DV-RPTR board guys will come up with a nice enclosure to match the board... although it would be a shame to hide this beautiful looking board away from view.

Wednesday
Sep262012

VK5REX B survives the 2012 D-Star QSO Party!

I was a little apprehensive of the potential thermal stresses the home-brew VK5REX UHF D-Star repeater was going to face during the 2012 D-Star QSO Party held this last weekend (21st-23rd Sep).

VK5REX B was linked to REF001 C most of the time, I'm sure that it was transmitting at least 95% of the time during the entire event.  The fan I am using for the transmitter cooling was deemed sufficient for "normal" use, but I wasn't quite sure how good it would be for long term high duty cycle operation.

My work required me to go to the repeater site on Monday morning (South Australia local time) during the end stages of the D-Star QSO Party.  I took the opportunity to do a "touch test" on the transmitter heatsink and was pleasantly surprised to see that it wasn't as hot as I thought it might be.

Mobile radios are generally not designed for high duty cycle operation so fan cooling is essential!

I had a fantastic time during this years D-Star QSO Party.  29 countries contacted, 135 overall contacts made.  Some of the more exotic countries I contatced included Guatemala, Mexico, Namibia and Russian Federation.  

REF001 C was very very busy and this is where I made most of my contacts.  I did use some of the great web pages out there to chase contacts.  http://www.nj6n.com/dplusmon provides a real time update of Dplus activity and of course http://www.dstarusers.org shows a good history of past transmissions on D-Star Monitor enabled repeaters around the world.  I used a DVAP Dongle and D-Star HotSpot to go "hunting" for contacts away from REF001 C.

I really hope that Icom conducts another D-Star QSO Party next year!