Outernet modem and LDPC using Octave

I’ve recently started a project to develop a L-band satellite modem with the good people at Outernet. The application is one way broadcast data into the developing world. The “earth station”, or user terminal hardware, is an Outernet LNB and purpose-built patch antenna connected to low cost USB SDR dongle receiver. The modem will . . . → Read More: Outernet modem and LDPC using Octave

FreeDV SM1000 v SSB demo

Great demo of FreeDV 1600 (SM1000 at one end) and SSB between AA6E and K5MVP. You can really notice the reduced audio bandwidth and ever present noise of SSB compared to FreeDV. This is just the start – we are gradually improving the low SNR robustness and speech quality of FreeDV. Thanks so . . . → Read More: FreeDV SM1000 v SSB demo

Dual Rav 4 SM1000 Installation

Andy VK5AKH, and Mark VK5QI, have mirror image SM1000 mobile installations, same radio, even the same car! Some good lessons learned on testing and debugging microphone levels that will be useful for other people installing their SM1000. Read all about it on Mark’s . . . → Read More: Dual Rav 4 SM1000 Installation

Codec 2 Masking Model Part 1

Many speech codecs use Linear Predictive Coding (LPC) to model the short term speech spectrum. For very low bit rate codecs, most of the bit rate is allocated to this information.

While working on the 700 bit/s version of Codec 2 I hit a few problems with LPC and started thinking about alternatives based on the . . . → Read More: Codec 2 Masking Model Part 1

A Miserable Debt Free Life Part 2

The first post was very popular, and sparked debate all over the Internet. I’ve read many of the discussions, and would like to add a few points.

Firstly I don’t feel I did a very good job of building my assets – plenty of my friends have done much better in terms of net worth and/or . . . → Read More: A Miserable Debt Free Life Part 2

Hamburgers versus Oncology

On a similar, but slightly lighter note, this blog was pointed out to me. The subject is high (saturated) fat versus carbohydrate based diets, which is an ongoing area of research, and may (may) be useful in managing diabetes. This gentleman is a citizen scientist (and engineer no less) like myself. Cool. I . . . → Read More: Hamburgers versus Oncology

Is Alt-Med Responsible for 20% of Cancer Deaths?

In my meanderings on the InterWebs this caught my eye:

As a director of a cancer charity I work with patients everyday; my co-director has 40-yrs experience at the cancer coalface.We’re aware there are many cancer deaths that can be prevented if we could reduce the number of patients delaying or abandoning conventional treatment while experimenting with . . . → Read More: Is Alt-Med Responsible for 20% of Cancer Deaths?

OLPC and Measuring if Technology Helps

I have a penchant for dating teachers who have worked in Australia’s 3rd world. This has given me a deep, personal appreciation of just how hard developing world education can be.

So I was wondering: where has the OLPC project gone? And in particular, has it helped people? I have had some experience . . . → Read More: OLPC and Measuring if Technology Helps

A Miserable Debt Free Life

I have a lifestyle that is different to many people, and I have been encouraged to write about it. According to my friends, I am “living the dream”. I get up in the morning and can choose to do anything I want. I don’t work for money any more. I’ve been able . . . → Read More: A Miserable Debt Free Life

FreeDV Robustness Part 7 – FreeDV 700B

For the last few weeks I’ve been working on improving the quality of the 700 bit/s Codec 2 mode. It’s been back to “research and disappointment” however I’m making progress, even uncovering some mysteries that have eluded me for some time.

I’ve just checked in a “FreeDV 700B” mode, and ported it to the FreeDV API . . . → Read More: FreeDV Robustness Part 7 – FreeDV 700B