"You" wrote in message
...
In article .com,
"W5DXP" wrote:

On Feb 25, 1:05 am, Steve Bonine wrote:
On the other hand, you occasionally see these flashlights or radios
that
are powered by a crank that winds a spring and as the spring unwinds
it
generates enough power to create light or run the radio. So the
technology has improved since the vintage model that we used for FD.
Maybe it's now efficient enough (and small/light enough) to be usable.

There's a big difference between powering a receiver and powering a
transmitter. I have a Sony that receives for many hours on a single
AAA battery. But 100 watts output from a transmitter cannot be
reduced below 100 watts of supplied power. Given that efficiency may
be around 50%, 200 watts of human generated energy is a heck of a
lot of calories. Need to lose some weight?
--
73, Cecil, w5dxp.com


It is well documented that a very "FIT" human male can output in
the 100 Watt range on a well designed peddle powered Generator.
Most of the WWII handcranked gensets powered radios in the 20
- 40 watt range. Australia' Peddle Powered HF Sets were also
in the 40 watt range.

There was a very interesting article in the latest Invention magazine about
the development of cell phones made possible only because of the short range
cellular concept and improved batteries.

As to human power... the Daedalus human powered airplane that flew the Greek
islands got its power from an athlete. The actual power that can be
generated from a human being for an extended period is something like one
tenth of a HP... in theory something like 75 Watts... but as has been shown
in this thread, seems like by the time all the juice goes through all the
resistors you only get something like 40 Watts.