Crystal ladder filter using 32.768 kHz watch crystals will give you around a 1 Hz bandwidth. 3 or 4 crystals and a few capacitors.. total cost = peanuts.
Featured in Technical Topics by Pat Hawker.
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http://www.rsgbshop.org/acatalog/GB2RS.html
ISBN 9781-9050-8639-9...
Current batteries are 100 - 200 times less dense than petrol.. Wh/kg. There are new battery technologies such as aluminium batteries and lithium-air which have much high Wh/kg.
Are you joking?? Power from Wi-fi It would take something like 100,000 hours to gather 1 Watt-Hour 2 metres from a 100 mW source. That is over 12 years! In practice you would get nothing because the received signal would be too weak to drive any type of rectifying diode into conduction.
Splitters are generally made of 1/4 wavelengths of coax cable. A 50 Ohm source can be fed to two 50 Ohm aerials. A 1/4 Wave of 75 Ohm cable with transform the impedance to roughly 100 Ohm.. Two in parallel brings you back to 50 Ohm. 4 x 50 Ohm aerials are combined using 1/4 Wave of 50 Ohm...
You need a decent size fan and that means quite a few Watts.
Solar panels are usually rated at maximum output which is only achieved on bright days and only when the Sun is square on to the panel. Typical output is far less than the max. You need to store the elec in a battery.
You will...
At the other end of the scale Profs in some of the World's most prestigious universities can be totally impractical thinking they can prove all sorts of stupid things with mathematics. Engineers with years of experience could tell them in a second they were talking nonsense.
The MIT Prof...
A real transformer does consume power with no load.
The output voltage is not the ratio of the turns x the input voltage for a real transformer... certainly not with with more than just a very light load on it.
Nah.
It will remain remarkable difficult for many decades if ever viable. The private sector won't get involved unless promised loads of public money which will never be forthcoming.
Space elevator? Another fantasy.
The proposal I saw was for 1GW of steerable solar panels which would cover an enormous area. The DC would be converted to about 2.4 GHz using thousands of magnetrons and then beamed to Earth with a 2 Km diameter dish. The dish would have a beamwidth of a tiny fraction of degree and therefore...
3 Phase AC and rotating fields were pioneered by John Hopkinson in Britain.
I would rate Tesla as a minor figure in science and engineering. Most of his 'things' were done before by other people. Folks were producing huge sparks with Nicholas Callan's induction coil when Tesla was a baby.
How can anybody seriously believe that Tesla could do things over 100 years ago that nobody has been able to repeat?
Tesla is the patron saint of crackpots.