Self Driving Cars

I’m a believer in self driving car technology, and predict it will have enormous effects, for example:

Our cars currently spend most of the time doing nothing. They could be out making money for us as taxis while we are at work.
How much infrastructure and frustration (home garage, driveways, car parks, finding a park) do we . . . → Read More: Self Driving Cars

FreeDV Robustness Part 6 – Early Low SNR Results

Anyone who writes software should be sentenced to use it. So for the last few days I’ve been radiating FreeDV 700 signals from my home in Adelaide to this websdr in Melbourne, about 800km away. This has been very useful, as I can sample signals without having to bother other Hams. Thanks John! . . . → Read More: FreeDV Robustness Part 6 – Early Low SNR Results

8 Mega Watts in your bare hands

I recently went on a nice road trip to Gippstech, an interstate Ham radio conference, with Andrew, VK5XFG. On the way, we were chatting about Electric Cars, and how much of infernal combustion technology is really just a nasty hack. Andrew made the point that if petrol cars had been developed now, we would . . . → Read More: 8 Mega Watts in your bare hands

Trellis Decoding for Codec 2

OK, so FreeDV 700 was released a few weeks ago and I’m working on some ideas to improve it. Especially those annoying R2D2 noises due to bit errors at low SNRs.

I’m trying some ideas to improve the speech quality without the use of Forward Error Correction (FEC).

Speech coding is the art of “what can I . . . → Read More: Trellis Decoding for Codec 2

WTF Internal Combustion?

At the moment I’m teaching my son to drive in my Electric Car. Like my daughter before him it’s his first driving experience. Recently, he has started to drive his grandfathers pollution generator, which has a manual transmission. So I was trying to explain why the clutch is needed, and it occurred to . . . → Read More: WTF Internal Combustion?

FreeDV Robustness Part 5 – FreeDV 700

We’ve just released FreeDV v0.98 GUI software, which includes the new FreeDV 700 mode. This new mode has poorer speech quality than FreeDV 1600 but is far more robust, close to SSB on low SNR fading HF channels. Mel Whitten and the test team have made contacts over 1000 km using just 1 Watt!

You can . . . → Read More: FreeDV Robustness Part 5 – FreeDV 700

New Charger for my EV

On Sunday morning I returned home and plugged in my trusty EV to feed it some electrons. Hmm, something is wrong. No lights on one of the chargers. Oh, and the charger circuit breaker in the car has popped. Always out for adventure, and being totally incompetent at anything above 5V and 1 . . . → Read More: New Charger for my EV

Lower SNR limit of Digital Voice

I’m currently working on a Digital Voice (DV) mode that will work at negative SNRs. So I started thinking about where the theoretical limits are:

Lets assume we have a really good rate 0.5 FEC code that approaches the Shannon Limit of perfectly correcting random bit errors up to a channel BER of 12%
A real-world code . . . → Read More: Lower SNR limit of Digital Voice

SM1000 Part 13 – Shipping!

The enclosure has arrived from the new manufacturer! Edwin and team at Dragino are now assembling, testing, and shipping the first batch of 100 SM1000s. We plan to ship all Aliexpress pre-orders in week starting 3 May, Australian orders the week starting 10 May.

We have sold almost all of the first batch . . . → Read More: SM1000 Part 13 – Shipping!

Minimalist VHF Software Defined Radio Part 2

Shortly after I published the first post on a simple VHF SDR, Brady KC9TPA started making suggestions about optimising the code. So I encouraged him to have a look into the transmit side. How can we take a baseband modem signal (like GMSK) and convert it up to a HF IF frequency like 10.7 . . . → Read More: Minimalist VHF Software Defined Radio Part 2