Tuesday, June 25, 2019

DV-Mega DVStick 30

Operation of Internet Radio has been discussed in the posts about the Inrico TM-7 and the RT-4 Radio. The DV-Mega DVStick 30 offers another system to experience both DMR and D-star Radio by simply plugging the device into a computer and running Blue DV by PA7LIM.  The DV-Mega DVStick 30 is available from CombiTronics for 95 Euro.

The DVMEGA DVstick-30 contains a codec by the manufacturer DVSI, the AMBE-3000©. This is a state-of-the-art codec chip, which supports various encoding systems. The DVstick-30 with suitable software can operate different systems like DMR or D-Star and in the future, may also operate with other systems as the software is developed.

A suitable software for use with the DVstick-30 is Blue DV by PA7LIM. This software is available for many platforms like Windows, some IOS versions (Ipad, Iphone) and Linux, and with suitable hardware (OTG capable) even on Android and IOS. Either the internal mic/speaker system in the computer or an external USB headset may be used. PTT keying is done via button defined by the software.

Before operating the system it is necessary to set up the program with personal details and server details for both DMR and D-Star.

The Set-up Screen is shown below

General Settings:

1) Call sign
2) Com Port
3) Can enter your Lat Lon
D-Star Settings

Change the Default reflector to your preference DCS 049 I is used in Ireland and has a lot of Northern Ireland Activity on it

DMR Settings

1) Your DMR ID
2) DMR Type - we use BM in Ireland      can be set to DMR PLUS
3) DMR Master - BM_IRELAND_2721
4) Password - passw0rd

IF DMR + is selected
1) Master - Phoenix F
2) Default Reflector - 4400 UK calling channel - Phoenix is not used in Ireland

Fusion only works on the receive side at present


1) Tick the AMBE box
2) Select the correct port
3) Select the speed that works best - try the highest first
4) Kill Timer - 3 mins

Click on save and go to the operating Screen

Click on AMBE to select Microphone and Speaker

Select Serial to enable the DVMEGA DVstick-30

Select DMR and the system will default to the BM Server and Reflector selected

Use the slide on the bottom Right hand side for PTT or designate the Space Bar as PTT.

To change Reflector or Talk Group insert the number in the box arrowed. Note that the slider to the right of the Reflector/Talk Group Box selects P for Private Call or G for Group Call.

One of the advantages of this system, is that it is possible to select a Talk Group on screen to sample the activity on it. If there is nothing another can be selected on screen. This makes it easy to find the active Talk Groups without having to go to the trouble of programming the radio and then finding that the Talk Group has little to no activity on it.

The same applies to D-Star as the system un-links and re-links to the new Reflector when selected selected.

Whilst this is a computer based system, it does provide good access into the D-Star and DMR networks with Yaesu Fusion to follow at some stage. There are plenty of avenues for experimentation here.

The The DV-Mega DVStick 30 does provide a quick and easy way to rapid cycle through,  select and test out Talk Groups and D-Star Reflectors prior to programming them permanently into a radio. The DV Stick also serves a good system to monitor D-Star and DMR Reflectors and Talk Groups.

Basically, if you want to try our D-Star and don't want to take out a mortgage, this is the item for you. At approximately 100 Euro and with the copy of Blue DV for windows this will have you fully functional on DMR and D-Star. The Down side is having to lug around a Laptop and ancilliary bits like a Headset and microphone.

What does the DVMEGA DVstick-30 do and how ?

All digital modes in ham radio require a voice codec (coder/decoder aka vocoder (voice codec)). The purpose of a codec is the transformation of voice into a digital data stream and vice versa, from digital information to analogue voice. During this transformation much happens inside the codec than just an analog/digital conversion. The goal is to reduce the data rate as much as possible, because this will require less bandwidth in the limited radio spectrum. This is achieved by reducing and compressing voice in various ways, on the analog and digital side. These procedures are quite elaborate and hard to develop and therefore well protected by patents.  

Since the digital ham radio systems borrow technology from commercial systems, the codec definitions have been adopted. Although there are free open source codecs available, these free codecs are not compatible with commercial systems because they use different protocols. Every digital radio for D-Star, DMR, P25, C4FM, NXDN etc contains such a codec chip as a component of the radio. All radios need such a a codec chip to transform the digital data into analog and vice versa. This is exactly what the DVMEGA DVstick-30 does.

The benefit of such a 'radio less' application in ham radio is the possibility to stay in touch with the friends at home when traveling without a radio, or where no suitable digital repeaters are nearby. The requirements for the Internet data rate are, thanks to the capable codec chip, quite low, usually an ISDN line with 64 kbps is absolutely sufficient.