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 me just how stupid internal combustion engines are.

Dad: So if you dump the clutch too early the engine stops.
Son: Why?
Dad: Well, a petrol engine needs a certain amount of energy to keep it running, for like compression for the next cycle. If you put too big a load on the engine, it doesn’t have enough power to move the car and keep the engine running.
Dad: Oh yeah and that involves a complex clutch that can be burnt out if you don’t use it right. Or an automatic transmission that requires a complex cooling system and means you use even more (irreplaceable) fossil fuel as it’s less efficient.
Dad: Oh, and petrol motors only work well in a very narrow range of RPM so we need complex gearboxes.
Dad thinks to himself: WTF internal combustion?

Electric motors aren’t like that. Mine works better at 0 RPM (more torque), not worse. When the car stops my electric motor stops. It’s got one moving part and one gear ratio. Why on earth would you keep using irreplaceable fossil fuels when stopped at the traffic lights? It just doesn’t make sense.

The reason of course is energy density. We need to store a couple of hundred km worth of energy in a reasonable amount of weight. Petrol has about 44 MJ/kg. Let see, one of my Lithium cells weighs 3.3kg, and is rated at 100AH at 3.2V. So thats (100AH)(3600 seconds/H)(3.2V)/(3kg)=0.386MJ/kg or about 100 times worse than petrol. However that’s not the whole story, an EV is about 85% efficient in converting that energy into movement while a dinosaur juice combuster is only about 15% efficient.

Anyhoo it’s now possible to make EVs with 500 km range (hello Tesla) so energy density has been nailed. The rest is a business problem, like establishing a market for smart phones. We’re quite good at solving business problems, as someone tends to get rich.

I mean, if we can make billions of internal combustion engines with 1000′s of moving parts, cooling systems, gearboxes, anti-pollution, fuel injection, engine management, controlled detonation of an explosive (they also make napalm out of petrol) and countless other ancillary systems I am sure human kind can make a usable battery!

Internal combustion is just a bad hack.

History is going to judge us as very stupid. We are chewing through every last drop of fossil fuel to keep driving to and from homes in the suburbs that we can’t afford, to buy stuff we don’t need, making plastic for gadgets we throw away, and flying 1000′s of km to exotic locations for holidays, and overheating the planet using our grandchildren’s legacy of hydrocarbons that took 75 million years to form.

Oh that’s right. It’s for the economy.

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

SM1000 Part 12 – Testing in the US

Walter, K5WH has one of the 3 pre-beta SM1000 units. He writes:

Here’s a pic of the operations setup of the SM1000 on the air today from Houston Texas, into my HPSDR radio. With average Power down to 3 watts even. Made successful contacts to Mel-K0PFX and Gerry-N4DV. After working the audio levels a . . . → Read More: SM1000 Part 12 – Testing in the US

FreeDV and Codec 2 2015 Road Map

Last week I had a great chat with Gary Pearce KN4AG from Ham Radio Now:

Which brings me to my plans for 2015……..

2015 Open Digital Voice Road Map

I’m pretty excited about where Open Source Digital Radio is going in 2015. My goals for this year are:

A “sub zero” negative SNR FreeDV HF mode.
VHF FreeDV mode(s) that . . . → Read More: FreeDV and Codec 2 2015 Road Map

SM1000 Part 11 – Accepting Pre-orders!

The first batch of 100 SM1000s are being built in China right now and we estimate shipping will start in late March April. Due to popular demand I am accepting pre-orders right now!

Australian customers can buy directly from my Store, rest of the world please use the Aliexpress Store for direct shipping from . . . → Read More: SM1000 Part 11 – Accepting Pre-orders!

Minimalist VHF Software Defined Radio Part 1

I think the future of radio hardware is a piece of wire connected to a GPIO pin.

The rest of the radio will be “gcc compilable” free software running on commodity CPU horsepower. I spoke about this at length in my recent 2015 talk.

For the last two weeks I’ve been developing a simple radio architecture . . . → Read More: Minimalist VHF Software Defined Radio Part 1