UDRC

A Short UDRX and UDRC Update from MicroHAMS 2016

John Speaks on DV Modes at MicroHams

Introducing the UDRC

Universal Digital Radio Controller
–UPDATED–

Here at NW Digital Radio we are always looking at ways to enhance digital communications for the radio amateur. As we have been marching forward with the development of the UDRX-440 there have been a few products that have come to market both from us and from other manufacturers.

When designing the UDRX-440 we wanted to enable D-STAR voice communications and designed a daughter card to provide the AMBE vocoder. We choose the DVSI AMBE-3000™ chip which has the potential of providing superior voice reproduction on D-STAR, but also supports AMBE+2 which is used by other radio standards such as DMR, NXDN, Yaesu Fusion, APCO P25 Phase 2, … We created the DV3000, which is available as a standalone product along with the open source AMBEServer to make AMBE vocoding available over a network. This Raspberry Pi shield rapidly gained a following and hundreds are now deployed around the world. Later, we created a USB connected version of this device called the ThumbDV™, which has opened up AMBE vocoding to hundreds of additional users.

When Yaesu offered their new DR-1X Fusion repeater to clubs for $500  (updated information), the Northwest Digital Radio Club (not part of NW Digital Radio company) purchased one and put it on the air in Edmonds, WA as NW7DR.  The half rate digital voice is very good and the full rate voice is excellent. It wasn’t long before John (K7VE) looked at the external accessory adapter and wondered if the repeater could also do D-STAR. After considerable research and experimentation using a Raspberry Pi B+/2 for control and a DVRPTR V1 GMSK modem it was discovered that the DR-1X made an excellent D-STAR repeater. By comparison, John’s Kenwood based repeaters often run significant BER (bit error rate) on receive, at one location the Kenwood runs around 7+% BER, while the DR-1X is at 0%. (The repeaters are co-located and both use the DVRPTR V1.)

At first, the experiments ran into a known lockup condition when using an external controller in combination with Yaesu Fusion Digital mode. With the latest generation firmware the DR-1X is able to provide D-STAR, Analog, and Fusion Digital all on the same channel on a per transmission switched mode.  Mode control is accomplished using GPIO pins on the Raspberry Pi.

NW Digital Radio looked at the Raspberry Pi control system and soon decided that a combination control board with integrated CODEC could be built as a hat for 40 PIN GPIO headers on the Raspberry Pi and thus is born the Universal Digital Radio Controller or UDRC.

With the addition of the UDRC, the DR-1X will operate in these configurations. (WIRES-X requires a Yaesu HRI-200 attached to an external radio)

  • With the latest 1.00 family of firmware on the DR-1X
    • D-STAR/Analog
  • With the latest 1.10 family (after December 2015) on the DR-1X
    • D-STAR/Analog
    • D-STAR/Digital Fusion
    • D-STAR/Digital Fusion/Analog

The UDRC does not transcode between D-STAR and Fusion, it allows the DR-1X to repeat D-STAR transmissions and use the ircDDBGateway to communicate with stations, linked reflectors and repeaters, STARnet Digital Groups, etc.  Analog, Digital Fusion, and D-STAR are switched at the repeater on a per transmission basis.

The UDRC is designed as a simple to install addition to the DR-1X, however, NW Digital Radio has kept the experimenter in mind by providing various headers to allow straightforward hardware modification for integration with other hardware and applications. The built-in CODEC also will be available via a amateur packet radio standard mini DIN-6 port for software developers to adapt other modes, e.g. Packet Radio, VOIP (Asterisk/IRLP/Echolink), Codec-2, … Additionally, all GPIO and audio pins are available as solder through pads.

Share your application ideas on the UDRC group.

Estimated price for the UDRC is $89.95