NW Digital Radio Blog page 9

DV3000 Back in Stock

We have have received another batch of 100 and all back-orders have been filled leaving about 70 in stock.

We’re working on some app notes as well.

Well that was quick …

The first 100 DV3000s are sold at the intro sale price and have been shipped to 10 different countries. We have started a new build cycle and are accepting back-orders. We intend to maintain units in stock after that.

Thanks for getting this off to a great start!

Preparing the Raspberry Pi for DV3000 Applications

See the basic installation instructions for the DV3000 and the dv3000d daemon in the document DV3000 – AMBEServer

Note: All production DV3000 units are configured for 230400 bps and do not have jumpers. 115200 bps is insufficient, but the board can be easily modified to add jumpers to configure baud rate, see the schematic at in the datasheet.

The dv3000d is the basic building block for the first set of applications for the DV3000.  It is a server which receives PCM audio over a UDP socket and returns AMBE or receives AMBE and returns audio.

DummyRepeater from the Yahoo! pcrepeatercontroller forum can access the daemon either locally or over a UDP/IP link. DummyRepeater in conjunction with ircDDBGateway will allow you to link to reflectors and repeaters around the world.  See notes.

You will also find utilities to convert between ‘wav’ and ‘dvtool’ or ‘ambe’ files in the ircDDBGateway file AMBETools.


DV3000 AMBE Card Available Now

The UDR supports an optional AMBE Vocoder card for D-STAR Digital Voice or DV. During the last prototype layout of the UDR, it occurred to me that there are over 2 million Raspberry Pis, so if we used the same connector as the Pi, it would have the following advantages.

  • Pi users would have access to AMBE
  • Software development would be in parallel with UDR development
  • Other cards made for the Pi could potentially be used on the UDR

Jonathan Naylor, G4KLX, has adapted his Dummy Repeater to work with the DV3000 on the Pi. This let’s hams talk over the D-STAR network using their computer instead of a radio. He also built several wav / AMBE conversion utilities for testing and comparison of different vocoders. Jonathan joined us at Hamvention for the release of the DV3000, where we sold over 30 units.

The AMBE3000 Chip supports vocoding for:

  • D-STAR – Supported NOW by G4KLX
  • DMR and dPMR
  • Yaesu Fusion
  • P25 Phase 2

Check out the DV3000DS or go to the PRODUCTS page to buy online.

There is a Hamvention special for $89.00, which will be honored for 1 month or until the first run of 100 is gone.

Receiver Sensitivity

Just out of the RF Lab, the receive chain with 25kHz IF is fully functional and initial testing shows a MDS (Minimum Detectable Signal) of better than -130dBm (0.07 uV). That’s before any process gain in the modem section. We will release complete Eb/No curves for the receiver prior to shipment.

Here’s a sample of the receiver performance at 440MHz. Dennis hooked a key up to his Agilent Sig-Gen. Note if you were actually working CW you’d add in a SW narrowband audio filter after the 25KHz IF stage.

-100dBm -110dBm -120dBm -130dBm


This completes initial testing of the LNA thru the IQ XCVR and into the processor. The 100kHz IF stage needs some changes in the SAW filter circuit, so we can’t check that off just yet.


UDRX is on the air

We have the Transmit side of the RF deck checked out and operational. This includes the 9600 FSK Modem and 25kHz IF stages.

Dennis is working on the 100kHz IF while I’m checking out the TX/RX switch.

Keep the faith,
Bryan K7UDR

DDS Success

We redesigned the DDS (Direct Digital Synthesizer) for prototype II because it wasn’t meeting design goals for phase noise after being up-converted to our 740MHz LO.

LO = (Fout-IF)*2

Noise present in the LO appears in the final output and limits the amount of amplification available. This is why many HTs and other integrated radio products cannot be attached to power amps and stay legally in the channel.

The new design is working now and tests show adequate margin to take this design to production. This is a significant milestone behind us and puts us one large step forward to production.

Bryan K7UDR

To learn more about PhaseNoise

Q1 Progress Report

Prototype 2 has come back from assembly and passed initial bring-up. It is now in RF characterization. I expect this prototype to be fully functional but require some changes for full power operation.

We will have a full report at the MicroHAMS Digital Conference.

Thanks for your patience,
Bryan, K7UDR

Band Limited SDR …

… and a lot of other stuff

From my 2013 DCC Presentation.

Thanks to Gary Pearce of  HAMRADIONOW.tv for his videography.

Rag Chew in Portland OR

I’ll be speaking with the hams of TERAC on Thursday evening for anyone in the Portland OR area that is interested in the latest developments on the UDRX.

Pre-Meeting Dinner at 6pm
Meeting starts at 7:30

Max’s Fanno Creek Brew Pub
12562 SW Main St
Tigard OR 97223