<?xml version="1.0" encoding="UTF-8"?>
<Instrument xmlns="https://metadata.pithia.eu/schemas/2.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="https://metadata.pithia.eu/schemas/2.2 https://metadata.pithia.eu/schemas/2.2/pithia.xsd">
<identifier>
<PITHIA_Identifier>
<localID>Instrument_EISCAT_VHF</localID>
<namespace>eiscat</namespace>
<version>1</version>
<creationDate>2022-10-03T10:53:00Z</creationDate>
<lastModificationDate>2022-10-19T09:01:20Z</lastModificationDate>
</PITHIA_Identifier>
</identifier>
<name>EISCAT VHF Incoherent scatter radar</name>
<description>
An incoherent scatter radar transmits a VHF or UHF radiowave of
high power and a tiny fraction of the power is scattered
back. The spectrum of the scattered signal depends on plasma
waves propagating in the ionosphere and from the shape of the
spectrum the temperature of electrons and ions can be
determined. The scattered power or electron plasma frequency
shift can give the electron density and the Doppler shift gives
the ion drift velocity. The EISCAT Tromsø VHF radar was taken
into use in 1985. It operates at 224 MHz and uses a 4-segment
parabolic cylinder antenna of 40x120 m, which can point to
zenith or low elevatin northward. The transmitter and receiver
are split in two halves each connected to two of the
segments. Only one half can transmit due to a klystron failure.
The system nevertheless operates at a peak power above
1 MW.
</description>
<type xlink:href="https://metadata.pithia.eu/ontology/2.2/instrumentType/IncoherentScatterRadar"/>
<operationalMode><InstrumentOperationalMode>
<id>isr</id>
<name>IncoherentScatter</name>
<description>
The main use of incoherent scatter radars is ionospheric
research, where coded pulses are transmitted and
received. Decoding gives autocorrelation function estimates
at selectable time and range resolutions, and theoretical
scatter spectra can be fitted to these using standard
Fourier transform theory. The VHF radar operates at 224 MHz
which also makes it useful for D layer and mesospheric
research (PMSE, PMWE).
</description>
</InstrumentOperationalMode>
</operationalMode>
</Instrument>
