your cell phone can be located even when turned off

[AnotherOneAmerican]

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

No need to imply, he was British. (father Italian, mother British)

Very posh British family who owned 'Jameson & Sons' whiskey distillers and Daphne Castle in Ireland.

Edited July 29, 2013 by AnotherOneAmerican

[hawker9000]

Batteries were non essential for communications even 40 years ago....

A crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no battery or power source and runs on the power received from radio waves.

And how do you think the readio waves were generated without power?

"Even 40 years ago"? LOL - you mean back in the prehistoric 1970s?!

Anyway, no, they weren't. Being able to generate RF waves and receive them are two different things. Transmitters do require power; crystal receivers do not, but can only produce a weak sound (practically-speaking requires some kind of headset) and tune not-too-distant stations. If a cellphone is able to transmit anything with the battery removed, or actively respond to an external signal, then it's got some other internal secondary power source. I guess that's possible with some phones, but I really don't think any such phones are in common use. Some transceivers, and PCs for that matter, can generate detectable electromagnetic fields and be detected in the process of receiving and amplifying an incoming signal (sensitive communications involve the use of metallic shielding to prevent this), but if so then they too must have a power source to begin with.

As a practical matter, take the battery out of your phone and unless it was issued to you by the CIA, NSA, etc., it's almost certainly untrackable. If your phone has no fancy "wake-up on alarm" functions or settings that make things happen even when the phone is OFF, then powering it down (not just sleep, hibernate, screen off, etc.) probably does what you think it should do.

[slipperylobster]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

[slipperylobster]

Putting all this together. Ok, I can see that radio waves generate enough power to a receiver to activate it some way. You can actually listen to a broadcast. This is called converted energy. The design a a cellphone must incorporate this technology in the forms of a "diode". Perhaps, stored current is retained in phone, even after the battery is taken out. Therefore perhaps a radio wave can activate a switching system that uses the stored powered in the circuitry to return a signal. That signal would only need a short burst of power and a "handshaking system" and thus transmit stored information (binary). I really don't know...but 100 years after Marconi, I suppose it is being done regardless. Perhaps Microwave Communications capitalize on this basic knowledge of converting radio frequencies into energy (power). So whats all the hoopla about?

[slipperylobster]

Oh...I forgot, here is some other food for thought, in the form of a link. Next time you think somebody from the NSA is trying to listen to you/locate your phone when its powered off, consider this consortium... I, err, kinda sorta figured it was not publicized, but I located it so its public knowledge...

http://en.wikipedia.org/wiki/AUSCANNZUKUS

lol..whose the bad guys?

And, Hey, build your own Radio Receiver (No batteries/electrical power required)...

http://www.wikihow.com/Make-a-Crystal-Radio

[JakeBKK]

Yes, I do understand the confusion among concerned international communities. Historically speaking, the Brits, I believe, were the first to crack the Japanese code before Pearl Harbor. I will present to you that they indeed knew of the oncoming invasion, but were unable to release the knowledge of their capabilities. Did I not hear of a clandestine national effort (In England) to monitor communications abroad during that period of time?

https://en.wikipedia.org/wiki/Bletchley_Park

i'll guess the have moved, since.

Yes they've moved to here:

this is a bit more fancy...on the other hand we are not at war with the germans any more. wait, we are at war against terror. or it was Boris Johnson's haircut, i can't remember.....

Edited July 29, 2013 by JakeBKK

[canman]

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

No need to imply, he was British. (father Italian, mother British)

Very posh British family who owned 'Jameson & Sons' whiskey distillers and Daphne Castle in Ireland.

He was born and died in Italy, went to Cambridge and every reference i have seen to him says he is Italian.

[canman]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

My reply was aimed at addressing the opening line of your post: "Batteries were non essential for communications even 40 years ago...." Just pointing out that a power source was required for the transmit side of radio communications. I see that you do understand that. I built a couple crystal sets as a kid, with a good earth and a long antenna I could pull in SW stations from all around the world on a good night.

The pupose of the crystal is that it simply acts as a diode, you could also get the same effect by substituting a razor blade and a thin wire "cats whisker" set I think they were called.

[canman]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

My reply was aimed at addressing the opening line of your post: "Batteries were non essential for communications even 40 years ago...." Just pointing out that a power source was required for the transmit side of radio communications. I see that you do understand that. I built a couple crystal sets as a kid, with a good earth and a long antenna I could pull in SW stations from all around the world on a good night.

The pupose of the crystal is that it simply acts as a diode, you could also get the same effect by substituting a razor blade and a thin wire "cats whisker" set I think they were called.

[canman]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

My reply was aimed at addressing the opening line of your post: "Batteries were non essential for communications even 40 years ago...." Just pointing out that a power source was required for the transmit side of radio communications. I see that you do understand that. I built a couple crystal sets as a kid, with a good earth and a long antenna I could pull in SW stations from all around the world on a good night.

The pupose of the crystal is that it simply acts as a diode, you could also get the same effect by substituting a razor blade and a thin wire "cats whisker" set I think they were called.

[slipperylobster]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

My reply was aimed at addressing the opening line of your post: "Batteries were non essential for communications even 40 years ago...." Just pointing out that a power source was required for the transmit side of radio communications. I see that you do understand that. I built a couple crystal sets as a kid, with a good earth and a long antenna I could pull in SW stations from all around the world on a good night.

The pupose of the crystal is that it simply acts as a diode, you could also get the same effect by substituting a razor blade and a thin wire "cats whisker" set I think they were called.

Yes. I enjoyed DXing as well...never built a receiver, Ordered a Kenwood (forgot the model) superheterodyne. Could separate sidebands and stuff. Had quite a pocket full of QSL cards from around the world (1972), that "went missing". Had a good location on the island of Crete (at 17 years old)

[JakeBKK]

Bit OT , never mind. i had pulled mr Heinrich hertz which is a bit more on the head. But i join the club. president Lincoln 11 m and various 2m and 70 cm gear good times.

[Somtamnication]

Batteries were non essential for communications even 40 years ago....

A crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no battery or power source and runs on the power received from radio waves.

And how do you think the readio waves were generated without power?

http://www.youtube.com/watch?v=glHxEkyulEU

[harrry]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

Poor guy must have had to live on gnochi every day. Of course a capacitor could probably hold enough charge to power the locator.

[hawker9000]

Think "Crystal" and research a man in Britain called "Marconi". He was powering radio receivers in the year 1910, without electricity. dam_n receiver was powered by remote radio waves. I hate to belittle your intelligence, but its ancient history.

The first radio transmitters were spark gap transmitters. They required electricity to provide the spark. Where did you get your information that Marconi did not use electricity to generate RF energy ie radio waves?

You seem to imply that Marconi is British (a man in Britain called "Marconi")? Marconi was Italian

As to your first issue about "transmitters" , you are correct. However, I was only referring to a "Crystal Receiver" and my information is correct on that. You can just google it, but here is a link that explains it all. A "Crystal" receiver requires no internal power. The power comes from incoming radio waves. Here is the link

http://en.wikipedia.org/wiki/Crystal_radio

Father's name Italian, Mom was "Irish". His company was founded in England... I suppose his birth was "Italian" and his name was "Italian" for sure..... I may read further on it, but he kind of stayed in the British Empire quite a while, with his cousin...lets call it 50/50. Here is the link for that.

http://www.marconisociety.org/aboutus/familyhistory.html

I do give you credit for mentioning that the Transmitter needed power and that Marconi's father was Italian. But read more closely my post concerning the "Crystal Receiver" and lets just say it was invented by a man fathered by an Italian and Mothered by an Irish lady. Smart man for sure.

Poor guy must have had to live on gnochi every day. Of course a capacitor could probably hold enough charge to power the locator.

For a cellphone? Nah. Such a capacitor can't hold charge for more than a few seconds. I've heard of "super caps" which can maybe hold a small charge for up to a few hours at most.