Orchid XP v3 wrote:
>>>> Why do you think that those frequencies are far above 50 Hz?
>>>
>>> My engine *idles* at several thousand RPM...
>> The significant character here is 'M'
> 
> Hmm. What is 2,000 RPM in Hz? 33 Hz? That's interesting...
> 
>>>> What sound does your motor make? Can you find the base frequency on 
>>>> your keyboard?
>>>
>>> Surely that's just the resonant modes of the exhaust system and the 
>>> chasis?
>>>
>> Whatever it is, that is what you see. If it moves faster than 50 Hz 
>> you either see it not moving at all or, viewed in the right direction, 
>> as a semitransparent surface.
> 
> AFAIK, the retina sees the "integral" of incident light over time, 
> roughly. 
Not really
> So I'm not sure why an object moving fast enough would appear 
> to stop moving. Become invisible, perhaps, if it's small enough...
> 
>> If you can prove that you can see something moving at, say 200 Hz, I 
>> have a couple of friends working on the retina that would be most 
>> interested in such a physiological anomality. ;)
> 
> How about my tuning fork? That says "440 Hz" on it, and I can see that 
> vibrating plainly enough... ;-)
Again the question is if you see the 440 Hz or a much lower frequency 
wobble. The ends of the fork should be a little wider and a little 
transparent. Anyway I think what you see is that it is moving, not the 
movement itself.
> 
> (Oddly though, it doesn't seem to make much audible sound, despite the 
> ends of the fork traversing really quite some distance. I can only 
> surmise that it doesn't move the air around very much or something...)
> 
Perhaps otherwise it would loose energy too fast and the tone would die 
out quickly.

Post a reply to this message

46D### [at] hotmailcom...
>>
>> (Oddly though, it doesn't seem to make much audible sound, despite the 
>> ends of the fork traversing really quite some distance. I can only 
>> surmise that it doesn't move the air around very much or something...)
>>
> Perhaps otherwise it would loose energy too fast and the tone would die 
> out quickly.
Think of a big impedance mismatch between the fork and air.
You get a better match when you put the round end on a thin hard surface as 
a guitar top or a box.
Then the vibrating surface is much bigger and can transmit energy to the 
air.
Note that the sound dies faster then.

Marc

Post a reply to this message

On Tue, 04 Sep 2007 10:13:37 +0200, scott wrote:

> Of course if you are in a call average power use will be much higher,
> which is why "talk-time" is something like 8 hours and "standby time" is
> usually a week or so.

I don't know anyone who gets that kind of standby time.  My phone (which 
is fairly new) only gets about a day, maybe two of standby time.  Course 
I use it for other things (like navigation) which cut down on the 
available battery, natch.

Jim

Post a reply to this message

On Mon, 03 Sep 2007 16:40:09 -0700, Darren New wrote:

> Depends on the phone system. CDMA was originally designed to be an
> undetectable transmitter for military use. IIRC, its power ranges
> between 2.5mW and 5mw.

That sounds like the range I was thinking of.  1 mW isn't very much.

Jim

Post a reply to this message

"Orchid XP v3" <voi### [at] devnull> wrote in message 
news:46dda414$1@news.povray.org...
>>> And when I start up the engine of my car, the various parts move far too 
>>> fast for the eye to follow. But you *can* see the blur of moving 
>>> objects, and there is little doubt that they're moving. ;-)
>
>> Why do you think that those frequencies are far above 50 Hz?
>
> My engine *idles* at several thousand RPM...

No it doesn't!

What kind of engine do you run in your car???  a nitro engine???

Any car engine is capable of idling far below 1000rpm.  Most idle aroun 
600-800rpm depending on auto or manual gearbox...

HTH

Cheers Dre

>> What sound does your motor make? Can you find the base frequency on your 
>> keyboard?
>
> Surely that's just the resonant modes of the exhaust system and the 
> chasis?
>
> -- 
> http://blog.orphi.me.uk/

Post a reply to this message

> Nah, one of these :)
>
>
http://www.peoplepoweredmachines.com/reel_mower_landing.htm?gclid=CJjJm8adqY4CFQsEIwod4SvTSw

Ah, I thought they ran on beer =)

Post a reply to this message

Gail Shaw wrote:
> "Orchid XP v3" <voi### [at] devnull> wrote in message
> news:46dc4c7a$1@news.povray.org...
> 
>>John VanSickle wrote:
>>
>>
>>>>Damn... pitty we can't use heat to do *useful* stuff!
>>>
>>>Heat already does useful things.  For instance, it causes cute girls to
>>>wear skimpy clothing.
>>
>>Hey, neat!
>>
>>(Pitty it's too damn hot to do anything about it...)
>>
> 
> 
> Two words...
> 
> Swimming pool

Which results in--even skimpier clothing!  Win-win!

Regards,
John

Post a reply to this message

Dre wrote:
> No it doesn't!
> 
> What kind of engine do you run in your car???  a nitro engine???
> 
> Any car engine is capable of idling far below 1000rpm.  Most idle aroun 
> 600-800rpm depending on auto or manual gearbox...

I've seen several engines that idle at more than 1000rpm.  I even saw 
one go as high as 1 800 (though I'm pretty sure there was something 
wrong with it).

-- 
...Ben Chambers
www.pacificwebguy.com

Post a reply to this message

Orchid XP v3 wrote:
> AFAIK, the retina sees the "integral" of incident light over time, 

Errr, not even close. Indeed, if something is completely still, you 
can't see it at all. That's why your eyes are always moving (saccades).

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

Post a reply to this message

Chambers wrote:
> Dre wrote:
>> No it doesn't!
>>
>> What kind of engine do you run in your car???  a nitro engine???
>>
>> Any car engine is capable of idling far below 1000rpm.  Most idle
>> aroun 600-800rpm depending on auto or manual gearbox...
> 
> I've seen several engines that idle at more than 1000rpm.  I even saw
> one go as high as 1 800 (though I'm pretty sure there was something
> wrong with it).
> 

My 4 stroke, 49.9 cc moped engine idles at 1800 to 2200. That is, if the
manual is to be trusted, since in all three places it lists an ideal
idle speed it has a different number. But, there is a difference between
cars, and chainsaw motors with wheels.

Post a reply to this message