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Comment: Re:For that matter... phones. (Score 1) 790

by Hank the Lion (#48793311) Attached to: Ask Slashdot: Sounds We Don't Hear Any More?

I dialed phone numbers by rapidly depressing the hook. Worked like a charm.
I then found out that 11 pulses followed by a few (2 or so) 'normal' digits would also give you a connection.
Judging by the response I got, I presume this was a number within the telephone company.
I was 10 years old at that time, so I hung up in a hurry ;-)

Comment: Re:We Wish (Score 1) 663

by Hank the Lion (#43602637) Attached to: Ask Slashdot: What If We Don't Run Out of Oil?

If it would consume more energy to produce a solar panel than it will produce in its lifetime, then either:
- I would not be able to ever recoup my investment (but I can with current energy prices reach this in 15 years), or
- Solar panel producers pay far less for their energy than I do, or
- they would make a loss and go bankrupt.
The price of a solar panel will (except for subsidies) never be lower than the price of the energy needed to produce it.
As long as I can install one and make a profit, I don't believe that producing it will have cost more energy than it will ever produce.

Comment: Re:Fuel costs money (Score 1) 587

by Hank the Lion (#43348267) Attached to: Samoa Air Rolling Out "Pay As You Weigh" Fares

Why isn't this reasonable? If I send a package by airmail, I pay by weight, even if I don't have the option of making the package lighter.
Why should that be any different if the package is myself? It will cost more fuel to transport me if I'm heavier, so why should other people bear that extra cost?

Comment: Re:Preach it (Score 1) 59

by Hank the Lion (#42320675) Attached to: Researchers Convert Phones Into Secret Listening Devices

So if the ringer was ringing and you pick up the phone there might leak some of the 90 V signal into the microphone?

That wouldn't be too good for the microphone.
The switches of the hook are there to prevent that.
They connect/disconnect in such an order that the telephone exchange is signalled that you pick up the receiver so the ringer signal is switched off before the speaker and mic are connected. I once had a telephone where this dis not work properly. When you picked it up at the exact moment of a ring, a loud buzzing sound came out of the earpiece. Not nice.

And did you consider what happens if you put a High frequency signal onto the line? Some of the signal might be affected by the condensator combined with the mic, and a usable signal might gotten of it.

If the receiver is on hook, both mic and speaker are completely disconnected, as you can see.
The capacitor is in series with the ringer, not with mic/speaker.
Please let me know from the schematic (the one I linked to, or another one if mine is not correct for the phone you have in mind) what exact signal pathway you have in mind. "Some of the signal might be affected" is too vague to be refuted or confirmed.

Comment: Re:Preach it (Score 1) 59

by Hank the Lion (#42320043) Attached to: Researchers Convert Phones Into Secret Listening Devices

Yes, I know the difference.
I have disassembled T65 telephones, myself, and I did not find any difference to the schematic I linked to.
That is why I asked you to post the schematic of the telephones you disassembled that were different.
Unless you can do so, and explain how a telephone off hook can be used to eavesdrop on you, you confirm my opinion that you are a troll.
A moderately competent one, I must say: I'm still feeding you...

Comment: Re:Yeah I remember that (Score 1) 64

by Hank the Lion (#42312975) Attached to: Current Radio Rules Mean Sinclair ZX Spectrum Wouldn't Fly Today

Yeah, the display hardware of the ZX81 was brilliant in its simplicity.
Not only did it use the program counter as the character point er for the display, but the I/R (interrupt and DRAM refresh) register pair was used as a pointer into the character ROM. These were output automatically by the processor directly after the fetch of the instruction.
And each line of the display was ended by a HALT instruction, so short lines did not need the full 32 bytes.
And, and, and... I loved that machine for its (albeit just a _little_ bit convoluted) design!

Comment: Re:Preach it (Score 2) 59

by Hank the Lion (#42312569) Attached to: Researchers Convert Phones Into Secret Listening Devices

I'm guessing you never disassembled one to see how it actually worked. I did. Go ahead and find an exemplar and give it a go.

OK, here is the schematic of the most widely used mechanical telephone in The Netherlands: the T65.
When the telephone is on hook ("hoorn"), only the ringer (bel) is connected to the line.
I really cannot think of another arrangement: the ringer voltage is high (100V?) so you don't want that appearing over your mic or speaker.
Please share with us the schematic of the phones you disassembled, or are you really a troll?

Comment: Re:Well I'm convinced it's true (Score 1) 216

Explaining it to the manufacturers of 900 kV stun guns will have no effect.
They know very well that their product does not reach 900 kV.
Those tasers may very well reach 90-100 kV (spark length of 3-3,5 cm), but not tenfold that.
It's just as with the 200W PMPO computer speaker sets that are supplied from a 12W transformer: pure marketing hype.

But, I agree with your main point: it is trivial to create a sufficiently high voltage in a small volume.
Even the simplest 2 kV fly swatter tennis rackets show that.

Comment: Re:Well I'm convinced it's true (Score 4, Informative) 216

I built a stun gun capable of generating 900,000 volts on-demand out of a few dollars worth of parts and a 9 volt battery, and it fits in the palm of your hand

900V or 9 kV I would believe, 900 kV not so much.
You would need creeping distances of more than 300 mm just to prevent arcing and making the voltage collapse before it even reached the 900 kV.
"900 kV" and "fits into the palm of your hand" are mutually exclusive, I think.
(and yes, I've designed and built multi-kV devices myself)

Comment: Re:An even more economical way to store electricit (Score 1) 295

by Hank the Lion (#41465495) Attached to: Microsoft Pollutes To Avoid Fines

Ah, the second link made things clear.
If you just compress air without adding water, it heats up.
This heat is lost over time, lowering efficiency.
When you spray in water, you take this heat loss up front, that is: if you don't re-use the heat in the water.
The brilliant thing LightSail Energy is doing is that they re-use the heat in the water on expansion.
And because the heat capacity of water is much higher than that of air, relatively little water is needed.

If you would just release the heat in the water to the environment (which I thought was what happened when you described the cooling step), efficiency would be lower than without the cooling step.

% APL is a natural extension of assembler language programming; ...and is best for educational purposes. -- A. Perlis