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Delivery is in the eye of the beholder

Just finished showing the APRS 9600 Transmit Demo at Pacificon.

Dennis has the IQ Receiver socket pushing data thru to his workstation allowing post processing of the eye pattern. Here’s a snapshot:


At this point we’re pretty comfortable with accepting orders for the UDRX this year for delivery in Q1!

I will continue to post progress updates as we move forward.

News from DCC in Austin

Basil has the complete AX25 stack bolted to the transmitter. Proto 3 was shown tossing 9600 APRS packets to a Yaesu VX-8 at DCC in Austin. This includes the socket interface with support for IPV4 and V6.

We are now doing compatibility testing with commonly deployed 9600 TNCs. We don’t anticipate any issues with any properly functioning TNC, this is just a verification list:

  • Kantronics 9612 plus
  • Timewave PK96
  • Yaesu VX-8
  • Kenwood D710

Dennis has a non-coherent receiver working (it actually does FM Voice) which is the front end for the decoder. He is also working on a coherent receiver for higher speed modems which will give us an additional few dB.

We will provide another update after Pacificon in a few weeks.

Keep the Faith,

UDRX Proto 3 has arrived

6 Units of the third, and hopefully final, UDRX prototype have arrived and passed power-up. We’ll release a complete project up-date at the TAPR/ARRL Digital Communications Conference in Austin TX on September 6th.

Hope to see many of you there,
Bryan – K7UDR


Customs Declaration

To our International Customers:

We all like to save money and don’t always agree with our Government’s Tax Policy.

But please, don’t ask us to falsify the customs declaration on your order.

Bryan K7UDR

International Shipping

I did a quick check today on our International Shipments via the US Postal Service.  Here are the results:


  • Australia
  • Canada
  • France
  • Netherlands
  • Poland
  • Spain
  • Switzerland
  • United Kingdom


  • Germany


  • Belgium
  • Ireland
  • Italy
  • Japan
  • Norway
  • Russia
  • Ukraine

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!

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