SM1000 Part 9 – First Betas

Edwin and his team at Dragino have hand assembled the first two SM1000 Beta units in Shenzhen. I’m working with him to perform some initial tests while we wait a few days for the prototype enclosures to be made. Then Rick and I will both get a SM1000 shipped to us for testing. . . . → Read More: SM1000 Part 9 – First Betas

SM1000 Part 8 – Video and Beta CAD work

Over the last few months Rick KA8BMA has been working steadily on the schematic, PCB, and enclosure CAD work for the SM1000 Beta. This is now complete, the Beta PCBs have been made, and the first 2 Beta units are being hand assembled by Edwin at Dragino. Rick and I will test these, then . . . → Read More: SM1000 Part 8 – Video and Beta CAD work

OpenRadio Part 3 – Filters

Over the past week I’ve built my own OpenRadio prototype, using the construction notes Mark has put together as a guide.

To help others I measured a few DC voltages and recorded them. I found one small bug in my assembly: one of the flip-flop pins was not soldered correctly, leading to erratic signals. After . . . → Read More: OpenRadio Part 3 – Filters

FreeDV Robustness Part 4

I’m working on increasing the robustness of FreeDV over HF radio channels, in particular compared to analog SSB.

Why HF Digital Voice so Hard

HF radio channels are bad news for digital data. Here is a plot of the Bit Error Rate (BER) versus Eb/No for two different modems (DQPSK and QPSK) and two different channels (AWGN and . . . → Read More: FreeDV Robustness Part 4

OpenRadio Part 2 – Prototype Works!

Since the first post on the OpenRadio project Mark has been moving ahead and leaps and bounds. In just a few late nights work he has assembled and tested the radio, managed to receive off air signals, and even tested the PSK31 transmitter! Fine business Mark.

Mark writes:

Hooked it up to a real antenna tonight:

That’s . . . → Read More: OpenRadio Part 2 – Prototype Works!

OpenRadio – a one day Software Defined Radio project

For the 2015 Linux Conference, I am working with Kim Hawtin and Mark Jessop on a 1 day Open Radio Mini-conference.

In this mini-conf a classroom of people will solder together their very own software defined radio (SDR) transceivers in just a few hours. It will be capable of receiving signals on the HF . . . → Read More: OpenRadio – a one day Software Defined Radio project

JackPair – Secure Phone Calls using Codec 2

I’ve just found out about a new Kickstarter for JackPair, a device that enables secure phone calls over a mobile phone. It uses Codec 2.

Over the past 12 months I have been approached by a couple of groups interested in building a similar product (but not JackPair). These groups asked me to develop a . . . → Read More: JackPair – Secure Phone Calls using Codec 2

SM1000 Part 7 – Over the air in Germany

Michael Wild DL2FW in Germany recently attended a Hamfest where he demonstrated his SM1000. Michael sent me the following email (hint: I used Google translate on the web sites):

Here is the link to the review of our local hamfest.

At the bottom is a video of a short QSO on 40m using the SM-1000 over about . . . → Read More: SM1000 Part 7 – Over the air in Germany

Degrowth Economy

Just read this article: Life in a de-growth economy and why you might actually enjoy it.

I like the idea of a steady state economy. Simple maths shows how stupid endless growth is. And yet our politicians cling to it. We will get a steady state, energy neutral economy one day. It’s just . . . → Read More: Degrowth Economy

SM1000 Part 6 – Noise and Radio Tests

For the last few weeks I have been debugging some noise issues in “analog mode”, and testing the SM1000 between a couple of HF radios.

The SM1000 needs to operate in “analog” mode as well as support FreeDV Digital Voice (DV mode). In analog mode, the ADC samples the mic signal, and sends it . . . → Read More: SM1000 Part 6 – Noise and Radio Tests