General Introduction

This is a Regional Research Center that belongs to the National Council of Research and Technology (CONICET). It is located within the limits of the town of Anillaco and has modern laboratories with high standard infrastructure and loadging facilities.

 

 

 

To see more details on the surveyed area click on the map

Crilar map

This facility could be used as a first headquarter of the SKA. RFI measurements taken at CRILAR indicate that numerous local man-made signals are present in the spectrum. A potentially much better site is located in Barreal de la Puerta de Arauco (an 8 x 14 km plain 22 km east from Anillaco and a mean altitude of 850 m).

This area has a mild slope (less than 50 meters over 14 km) and is shielded from the surrounding terrain by an incomplete ring-like chain of low altitude peaks.

Anillaco is linked to the national energy network by means of a threephase 13.2 kV line.

Road Access

This site can be easily accessed from the city of La Rioja (the capital of the homonymous province) by provincial paved routes RP7 and RP9.

The road network in this area is shown, along with the location of homesteads, towns and cities. Main geographical accidents are also marked.

Air Access

The province capital, La Rioja, is served by a national carrier (Aerolíneas Argentinas - Austral) once a day three days a week. The fly-time from Buenos Aires airport is almost 3 hours. The closest runaway to the site is located in Anillaco. Though there are no regular flights to this place, the runaway can very easily accommodate large cargo aircrafts.

Population density, nearest towns and major urban centers

Preliminary RFI measurements were carried out at a Research Center (CRILAR) of the National Research Council (CONICET) of Argentina. A string of low population towns (Pinchas, Chuquis, Aminga, Anillaco, Los Molinos, Anjullón) stretch over 25 km some 22-25 km westwards of Barreal de la Puerta de Arauco. Anillaco, the most populated, and Chuquis, the least populated, have 1365 and 261 inhabitants, respectively.

The city of La Rioja, the capital of the province,with its 106300 inhabitants is the closest major urban center.

Licensed Broadcast Transmitters

There are several local FM broadcasters within 75 km from Anillaco. These radios cover the frequency range from 89.1 till 107.7 MHz. Several low power microwave links are located in fix towers. The closest ones are only a few kilometres away from the place where the RFI measurements were obtained. Their registered nominal frequencies fall around 148, 157, 165, 335, 346, 454, 459, 467, 470, 1455, 1509, 1468 and 1522 MHz. Mobile phone services fall in the frequency range from 824 to 849 MHz and from 869 to 894 MHz. Information about individual transmitters, including geographical location, exact frequency of operation, antenna gain, antenna directivity, effective radiated power, etc. are available from the CNC and a comprehensive list is being assembled.

Geological characterization and Seismic Activity

The site is in the oriental watershed of Velazco Mountain. In this location alluvial flats are predominant. Crystalline bedrocks (granites, granodiorites, migmatites) of the Precambrian age are an important component of the mountain ridge. In the low and piedmont areas there is alluvial material of the Quaternary age. This fill is composed by the alternation of coarse sediments (gravel, coarse sand) and fine sediments (silt, clay). Though the seismic activity in this area is also of some importance, it is much lower than the one registered at CASLEO. Based on the world-wide earthquake catalog (Advanced National Seismic System) , within a circle of radius 100 km centered at CRILAR, eigth (8) earthquakes having an intensity magnitude superior to 5 were registered during the last 10 years. The average depth of their epicenter is 119.2 km and three (3) had an epicenter depth of about 30 km. The maximum acceleration likely to occur in La Rioja (Instituto Nacional de Prevención Sísmica) with a recurrency period of 50 year is 0.54 m/seg 2, a factor 4 lower than the one expected for San Juan.

RFI - Measurements

Typical RFI spectra for this site are shown in Figure 8 (10 - 200 MHz ) and Figure 9 (200 - 1100 MHz). The data for the first two bands are plotted in spectral flux density units of dBW m-2 Hz-1. Compared to CASLEO, these plots show much more electromagnetic activity in the lower two bands.

This is a direct consequence of the place chosen to carry out this preliminary RFI measurement. Since most of the signals present in the spectra have a local origin (mostly arise from fixed microwave tower links among Anillaco and neighbouring towns) they may not be detectable at a place like the one mentioned in Annex B (See pdf version). At the level of sensitivity of our measurements, the high frequency band is featureless.
A typical RFI spectrum in the frequency range 50 to 200 MHz at CRILAR. This spectrum is the result of integrating 130 minutes using a low gain biconic antenna directed at azimuth 0o and elevation 0o with horizontal polarization.
Typical RFI spectrum in the frequency range 200 to 1100 MHz at CRILAR. This spectrum is the result of integrating 460 minutes using a low gain biconic antenna directed at azimuth 22o and elevation 0o with horizontal polarization.

 


2004 - SKA Argentine Committee