Citaat:
Oorspronkelijk geplaatst door tatooke
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Zit ? Hoe komt ge daarbij ? Betrouwbare bron ?
N.B. Verwissel
Zenderfrequentie (
Transmitter) niet met
bandbreedte hé ? Volgens mij werken ze hoofdtzakelijk in de korte golfband (KW) (HF) voor de Tx-draaggolf.
http://nl.wikipedia.org/wiki/Korte_golf
http://en.wikipedia.org/wiki/High_frequency
http://de.wikipedia.org/wiki/Kurzwelle
Een VLF en ULF draaggolf is praktisch niet uitvoerbaar (theorie afmetingen golfpijp: Lambda/4, dus gigantische radars...), de zeer lage -voor mens en meeste dieren- onhoorbare frequenties VLF/ULF - zijn enkel door frequentiemodulatie op die draaggolf mogelijk. Maar de Haarpantennes zenden toch naar de
ionosfeer (zie tekening) heb ik zo gelezen.
PS. ik ben (ervaren) radarelectronicus. (1973-2009)
en van andere communicatietechniek (radio) ook -technisch- op de hoogte
In Wiki staan heel andere zendfrequenties:
http://en.wikipedia.org/wiki/High_Fr...search_Program
The HAARP project aims to direct a 3.6 MW signal, in the 2.8-10 MHz region of the HF band, into the ionosphere. The signal may be pulsed or continuous. Then, effects of the transmission and any recovery period can be examined using associated instrumentation, including VHF and UHF radars
...
HAARP approaches the study of the ionosphere by following in the footsteps of an ionospheric heater called EISCAT near Tromsø, Norway. There, scientists pioneered exploration of the ionosphere by perturbing it with radio waves in the 2-10 MHz range, and studying how the ionosphere reacts. HAARP performs the same functions but with more power, and a more flexible and agile HF beam.
Some of the main scientific findings from HAARP include:
1.Generation of very low frequency radio waves by modulated heating of the auroral electrojet, useful
because generating VLF waves ordinarily requires gigantic antennas
2.Production of weak luminous glow (below what you can see with your eye, but measurable) from absorption of HAARP's signal
3.Production of ultra low frequency waves in the 0.1 Hz range, which are next to impossible to produce any other way
4.Generation of whistler-mode VLF signals which enter the magnetosphere, and propagate to the other hemisphere, interacting with Van Allen radiation belt particles along the way
5.VLF remote sensing of the heated ionosphere
Research at the HAARP includes:
1.Ionospheric heating
2.Plasma line observations
3.Stimulated electron emission observations
4.Gyro frequency heating research
5.Spread F observations
6.Airglow observations
7.Heating induced scintillation observations
8.VLF and ELF generation observations <http://www-star.stanford.edu/~vlf/publications/2008-03.pdf>
9.Radio observations of meteors
10.Polar mesospheric summer echoes: PMSE have been studied using the IRI as a powerful radar, as well as with the
28 MHz radar, and the two VHF radars at 49 MHz and 139 MHz. The presence of multiple radars spanning both HF and VHF bands allows scientists to make comparative measurements that may someday lead to an understanding of the processes that form these elusive phenomena.
11.Research on extraterrestrial HF radar echos: the Lunar Echo experiment (2008).[5][6]
12.Testing of SS-Spread Spectrum Transmitters 2009
13.Meteor shower impacts on the ionosphere
14.Response and recovery of the ionosphere from solar flares and geomagnetic storms
15.The effect of ionospheric disturbances on GPS satellite signal quality
[edit] Instrumentation and operation
The main instrument at HAARP Station is the Ionospheric Research Instrument (IRI). This is a high power, high-frequency phased array radio transmitter with a set of 180 antennas, disposed in an array of 12x15 units that occupy a rectangle of about 33 acres (13 hectares). The IRI is used to temporarily energize a small portion of the ionosphere. The study of these disturbed volumes yields important information for understanding natural ionospheric processes.
During active ionospheric research, the signal generated by the transmitter system is delivered to the antenna array and transmitted in an upward direction. At an altitude between 70 km (43 mi) to 350 km (217 mi) (depending on operating frequency), the signal is partially absorbed in a small volume several tens of kilometers in diameter and a few meters thick over the IRI. The intensity of the HF signal in the ionosphere is less than 3 µW/cm², tens of thousands of times less than the Sun's natural electromagnetic radiation reaching the earth and hundreds of times less than even the normal random variations in intensity of the Sun's natural ultraviolet (UV) energy which creates the ionosphere. The small effects that are produced, however, can be observed with the sensitive scientific instruments installed at the HAARP Station, and these observations can provide information about the dynamics of plasmas and insight into the processes of solar-terrestrial interactions.[7]
Each antenna element consists of a crossed dipole that can be polarized for linear, ordinary mode (O-mode), or extraordinary mode (X-mode) transmission and reception.[8][9] Each part of the two section crossed dipoles are individually fed from a custom built transmitter, that has been specially designed with very low distortion. The ERP of the IRI is limited by more than a factor of 10 at its lower operating frequencies. Much of this is due to higher antenna losses and a less efficient antenna pattern.
The
IRI can transmit between 2.7 and 10 MHz, a frequency range that lies above the AM radio broadcast band and well below Citizens' Band frequency allocations. The HAARP Station is licensed to transmit only in certain segments of this frequency range, however. When the IRI is transmitting,
the bandwidth of the transmitted signal is 100 kHz or less. The IRI can transmit in continuous waves (CW) or in pulses as short as 10 microseconds (µs). CW transmission is generally used for ionospheric modification, while transmission in short pulses frequently repeated is used as a radar system. Researchers can run experiments that use both modes of transmission, first modifying the ionosphere for a predetermined amount of time, then measuring the decay of modification effects with pulsed transmissions.
There are other geophysical instruments for research at the Station. Some of them are:
A fluxgate magnetometer built by the University of Alaska Fairbanks Geophysical Institute, available to chart variations in the Earth's magnetic field. Rapid and sharp changes of it may indicate a geomagnetic storm.
A digisonde that provides ionospheric profiles, allowing scientists to choose appropriate frequencies for IRI operation. The HAARP makes current and historic digisonde information available online.
An induction magnetometer, provided by the University of Tokyo, that measures the changing geomagnetic field in the Ultra Low Frequency (ULF) range of 0–5 Hz.
http://de.wikipedia.org/wiki/HAARP
HAARP verfügt über eine leistungsfähige Phased-Array-
Kurzwellensendeanlage mit einer Sendeleistung (CW) von zurzeit 960 kW. Im Jahre 1993 wurde mit 18 zusammengeschalteten Elementen begonnen, 1998 wurde die Anzahl auf 48 erhöht. Im Endausbau 2007 sollen 180 Sender betriebsbereit sein. Die derzeitige Effektive Strahlungsleistung (ERP) liegt bei 84 dBW (250MW) und soll im Endausbau bei 96 dBW (4000MW) liegen. Die einzelnen Sender des Typs Continental Electronics D616G [2] mit jeweils 10 kW maximaler Sendeleistung wurden speziell für dieses Projekt entwickelt. Der von der Anlage nutzbare Frequenzbereich ist
2,8 bis 10 MHz (Kurzwelle). Zwei der von HAARP benutzten Frequenzen sind
3,39 MHz und 6,99 MHz. Des Weiteren befinden sich am Standort zu Zwecken der Ionosphärenbeobachtung eine Ionosonde und ein Riometer.[3]
Aja, bvb olifanten gebruiken -onhoorbare-mens- frequenties om met mekaar te communiceren.