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DV4 is a unit capable of handling most digital modes. D-Star, DMR, Echolink, PSK31, WSPR, RTTY



Here you can follow the progress of the DV4 development cycle. I am planning weekly updates.

June,21 2015 status:

DV4mini USB Stick:

The stick can be reserved, please see: www.helitron.de/shop. If you are interested, please register for a stick. This gives us an overview about the quantity and we can plan the first manufacturing lot accordingly. The software for Windows and Linux is ready. The stick will be shown on the Ham Radio fair by DG1HT (Hytera booth).


the layout for the first little series is done and in production. We will manufacture 6 pieces next week in order to show them on the Ham Radio fair and to test some details before we manufacture higher quantities. Another important decision was the type of interface between the single board computer and the DV4 hardware. We are now using an interface which makes it possible to use almost any single board computer like Raspberry, Odroid, Banana-PI and others (minimum requirement: dual-core).

June 3, 2015 status:

the story contunues: Today the DMR transceiver mode has been implemented and tested successfully. Now a direct QSO to a DMR handhald is possible. A mode which allows you to speak via repeaters will be done later when we get a couple of Hytera Repeaters for testing.

As you can see below in the softwar elist we are almost done. In order to use the time until the hardware is available we have decided to implement Fusion-C4FM (Yaesu). Maybe this is the opportunity for   C4FM to get a usable reflector connection, we will see.

Regarding the DV4 board: the final layout was planned for mid-June. It looks like this plan is realistic and we can start in early July the manufacturing of the pilot series.

June 2, 2015 status:

Today the TX direction of the DMR Hotspot was completed. Apart from the previous tests, the first real QSO happend at 22:00 between DJ0ABR (with PD365 handheld radio via DV4 Hotspot) and DL1BH on DMR 4012 and DH5RAE on DCS001V (D-Star DMR Gateway). The connection went fine with good modulation rapports. Thus the DMR Hotspot is finished and ready for use.

I know that many of you want to know when they can get a device. We will need about 2 weeks to the complete the work on the hardware and to do a calculation. I will keep you updated on this webpage.

June 1, 2015 status:

the next step is done: the DMR hotspot in RX direction. Today we did the first DMR digital voice transmission via DV4 Hotspot. The transmission path looked like that:

PD365 handheld  -->> DV4-Hotspot (Bavaria East) -->> DMR Reflector 4012 -->> Hytera Relais (Hamburg) -->> PD785 handheld  

The voice quality was good, a couple of OMs listened to these first tests.

May 31, 2015 status:

A small but extremely important step has succeeded. For the first time we were successful to receive the data of a DMR walkie talkie via radio on 70cm and for decode it correctly (without bit errors). From what we know it looks like a first worldwide in ham circles. This was the toughest hurdle and now we can concentrate on programming the DMR hotspots as planned. The DV4 will be the the worldwide first 70cm device that can handle D-Star and DMR and I hope to have more good news next weekend.

May 22, 2015 status:

This week we reached an important milestone. The first two-way DMR QSO with entirely home-brew units. Looks like a world premiere.

After over a year of research and programming OM Torsten (DG1HT) delivered the DMR Dongle Client and in a midnight session I inserted it into the DV4 prototype. After a short debug we conducted the first DMR QSO between Bavaria and Hamburg. The audio quality was excellent. The QSO was conducted via the DMR Reflector 4012.

This means the DMR Dongle mode is complete and we can concentrate on the 70cm Hotspot mode.


Prototype wiring development done
PCB layout of prototype done
Manufacturing prototype done
First operation of prototype done
Microphone amplifier done
Speaker amplifier ready but still needs testing
70cm transceiver done
AMBE Codec connection (Dstar+DMR) done
Display done
Selector knob done
Audio in and output and PTT done
WLAN (WiFi) done
ARM processor board done
enclosure selection  
finalizing circuit for pilot units in process
PCB layout of pilot units in process
manufacturing of pilot units  
operation of pilot units  
corrections for final series production  
series production  
tests and certifications  
available for orders with stock available  


Linux Device Driver done done
GUI driver (selector know, display ) done done
WLAN (WiFi) done done
Sound (microphone, speaker) done done
HDMI for external display done done
USB (keyboard, mouse etc) done done
D-Star hotspot done done
D-Star dongle mode done done
D-Star transceiver mode done done
D-Star conference mode done done
DMR hotspot in process done
DMR dongle mode done done
DMR transceiver mode done
DMR conference mode done
Fusion-C4FM hotspot in process  
Fusion-C4FM dongle mode done in process
Fusion-C4FM transceiver mode  
Fusion-C4FM conference mode  
Fusion-C4FM Reflector System FCS in process
implementation of FLDIGI (PSK31, RTTY ..) done
WSPR done


German guide  
interface descriptions regularly updated, see HERE
presentation material done