Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info
Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.
link to schematics here
Zoom Info

Making series of recordings in Prokopskie Udoli, Prague, using various VLF and All Band receivers. Currently working on other ones using Loop Antennas. Unfortunately I could hear mostly loads of hum and feedback between the antenna and the output.  In order to improve it ground wire must be stabilised.

link to schematics here

VLF, SID

Very low frequency or VLF is the ITU designation[1] for radio frequencies (RF) in the range of 3 kHz to 30kHz and wavelengths from 10 to 100 kilometres. Since there is not much bandwidth in this band of the radio spectrumaudio (voice) cannot be transmitted, and only low data rate coded signals are used. The VLF band is used for a few radio navigation services, government time radio stations which broadcast time signals to set radio clocks, and for secure military communication. Since VLF waves penetrate about 40 meters into saltwater, they are used for military communication with submarines. Also known as the myriametre band ormyriametre wave as the wavelengths range from one to ten myriametres (an obsolete metric unit equal to 10 kilometres).

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sudden ionospheric disturbance (SID) is an abnormally high ionization/plasma density in the D region of the ionosphere caused by a solar flare. The SID results in a sudden increase in radio-wave absorption that is most severe in the upper medium frequency (MF) and lower high frequency (HF) ranges, and as a result often interrupts or interferes with telecommunications systems.

When a solar flare occurs on the Sun a blast of intense ultraviolet and x-ray radiation hits the dayside of the Earth after a propagation time of about 8 minutes. This high energy radiation is absorbed by atmospheric particles, raising them to excited states and knocking electrons free in the process ofphotoionization. The low altitude ionospheric layers (D region and E region) immediately increase in density over the entire dayside. The ionospheric disturbance enhances VLF radio propagation. Scientists on the ground can use this enhancement to detect solar flares; by monitoring the signal strength of a distant VLF transmitter, sudden ionospheric disturbances (SIDs) are recorded and indicate when solar flares have taken place.

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Short wave radio waves (in the HF range) are absorbed by the increased particles in the low altitude ionosphere causing a complete blackout of radio communications. This is called a short wave fading. These fadeouts last for a few minutes to a few hours and are most severe in the equatorial regions where the Sun is most directly overhead. The ionospheric disturbance enhances long wave (VLF) radio propagation. SIDs are observed and recorded by monitoring the signal strength of a distant VLF transmitter. A whole array of sub-classes of SIDs exist, detectable by different techniques at various wavelengths: the SPA (Sudden Phase Anomaly), SFD (Sudden Frequency Deviation), SCNA (Sudden Cosmic Noise Absorption), SEA (Sudden Enhancement of Atmospherics), etc.

 

Live VLF Natural Radio

METEOR ECHOES : The US Air Force Space Surveillance Radar has been shut down, but we’re still recording meteor echos. How do we do it? Radio engineer Stan Nelson uses a Yagi antenna in New Mexico to detect 54 MHz TV signals reflected from meteor trails. When a meteor passes over his observatory—ping!—there is an echo. It’s the next best thing to a giant government radar!

More links:

super tiny VLF receiver

solar receiver

ELF receiver

WIRELESS TELEGRAPHY & THEORY OF ETHER (Sir Oliver Lodge)

life, matter and spiritualism  by Sir Oliver Lodge

SID stuff

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Homemade superheterodyne receiver 1920

An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info
An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info
An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info
An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info
An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info
An Attempt to build galena radio receiver  using:
-galena crystal
-coil
-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.
During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 
"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 
Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).
Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”
Zoom Info

An Attempt to build galena radio receiver  using:

-galena crystal

-coil

-capacitor

In 1876, a German scientist, Ferdinand Braun, discovered that the behaviour of galena (lead sulfide), depended on the nature of the connection made to it. Large area connections behaved very differently from those made using a fine point contact. Braun found that with a point contact the resistance of the junction depended on which way round the battery was connected. We call this property rectification and the device he created is called a diode.

Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, which was known as a "cat’s whisker". Making such wireless sets was a popular home hobby in Britain and other European countries during the 1930s.

During my experiments I noticed changes in resistance of galena while flashing the light. I am planning to expand on that. 

"The sulfides galena, chalcopyrite, and pyrite are semiconductors whose electrical resistivity and type are controlled by deviations from stoichiometry and impurity content, and hence by their geochemical environment. 

Spurious thermoelectric voltages on polished surfaces of galena, due to the polishing process, have been documented by Granvilleand Hogarth (1951).

Tauc (1953) suggested that these were due to electrically charged mechanical damage in a surface layer.”

Home-brewed LED
Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat’s-whisker detector. Russian Oleg Losev reported creation of the first LED in 1927.
H.J Round had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased.
Zoom Info
Home-brewed LED
Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat’s-whisker detector. Russian Oleg Losev reported creation of the first LED in 1927.
H.J Round had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased.
Zoom Info
Home-brewed LED
Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat’s-whisker detector. Russian Oleg Losev reported creation of the first LED in 1927.
H.J Round had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased.
Zoom Info

Home-brewed LED

Electroluminescence as a phenomenon was discovered in 1907 by the British experimenter H. J. Round of Marconi Labs, using a crystal of silicon carbide and a cat’s-whisker detector. Russian Oleg Losev reported creation of the first LED in 1927.

H.J Round had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased.

Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info
Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
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Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 
[source: http://en.wikipedia.org/wiki/Electrocardiography ]
In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.
[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]
I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626
Zoom Info

Electrocardiography is the recording of the electrical activity of the heart. Traditionally this is in the form of a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded or displayed by a device external to the body.[3] The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG). 

[source: http://en.wikipedia.org/wiki/Electrocardiography ]

In 1902, Einthoven published the first ECG recorded on a string galvanometer. This instrument used a thin, silver-coated, quartz string stretched across a magnetic field. The heart’s electrical current caused the string to move from side to side, which could be recorded photographically.
Einthoven’s early machine weighed 600 pounds and required five people to operate it. It was located in his lab at Leiden University in the Netherlands. By using a telephone cable, Einthoven was later able to transmit ECGs from patients in the hospital to the lab. In the next few years, several hospitals set up “electrocardiographic stations.” Smaller machines were soon developed, and in 1909, the first string galvanometer was installed in the US.

[source: http://news.nurse.com/apps/pbcs.dll/article?AID=2002208260360]

I am planning to build an electrocardiograph using AD620 ICs, home-made electrodes and modified CRT as a display. 

http://www.google.com/patents/US3793626