Attachment radhaz2

This document pretains to SES-MOD-20000630-01066 for Modification on a Satellite Earth Station filing.

IBFS_SESMOD2000063001066_152799

RADIATION HAZARD STUDY Satellite Education Network Western Illinois University Page 1 of 5 The satellite facilities at Western Illinois University are mounted on the southwest corner of Memorial Hall in Macomb, Il. The building is a 5 story building. Four of the five stories are used for offices, television studios, and classrooms. The uplink dishes are on the roof of the fourth floor. The fifth floor is to the east / northeast of the uplink dishes. The walls of the fifth floor is concrete block, brick and steel skin construction. The roof area that the uplink dishes are on is a controlled access area. Access is not available to anyone except maintenance workers. All equipment that would be accessed by these workers is on the east side of the fifth floor structure. The 6.1 meter Vertex dish is mounted on the Southwest corner of the building. Because of the location of the support steel, the reflector is flush and/or overhangs the edge of the roof. The edge of the reflector is 3 meters above the roof. The 2.4 meter Vertex dish is approximately 10 meters behind the 6.1 meter dish. It is a fixed dish that is positioned on Galaxy 10R at 123 degrees west. The reflector is accessible from the roof as it is 2 meters from the roof.

RADIATION HAZARD STUDY Satellite Education Network Western Illinois University Page 2 of 5 Region Radiation Hazard Assessment Level Mw/cm² Far Field (2.4m Vertex) 1.49 Complies with guidelines Rff = 17280 cm² (6.1m Vertex) .507 Complies with guidelines Rff = 111630 cm² Combined 1.997 Complies with guidelines Near Field (2.4m Vertex) 3.27 Complies with guidelines Rnf = 30 cm² (6.1m Vertex) 1.08 Complies with guidelines Rnf = 76 cm² Combined 4.35 Complies with guidelines Reflector Surface (2.4m Vertex) 1.64 Complies with guidelines (6.1m Vertex) .531 Complies with guidelines Combined 2.171 Complies with guidelines Transition Region (2.4m Vertex) .04 Complies with guidelines (6.1m Vertex) .002 Complies with guidelines Combined .042 Complies with guidelines

RADIATION HAZARD STUDY Satellite Education Network Western Illinois University Page3 of 5 Region Radiation Hazard Assessment Level Mw/cm² Transition Region Str (2.4m Vertex) 3.27 Complies with guidelines (6.1m Vertex) 1.08 Complies with guidelines Combined 4.35 Complies with guidelines Between Antenna and roof (2.4m Vertex) .02 Complies with guidelines (6.1m Vertex) .01 Complies with guidelines Combined .03 Complies with guidelines Between Main reflector and feed (Figures are based on power level At the feedhorn.) (2.4m Vertex) 163.58 Potential Hazard (6.1m Vertex) 610.09 Potential Hazard Combined Not Physically possible. The 2 feeds are separated by over 10 meters. Conclusion: Based on the above analysis, it is concluded that harmful levels of radiation will not exist in the regions normally occupied by the public or employees of the university. The earth station will be marked with standard radiation hazard warning signs that will described where the potential may exist for hazardous radiation levels. To ensure compliance with the safety limits, the earth station transmitter will be turned off whenever maintenance and repair personnel are required to work in the area where the radiation level exceeds the level recommended by applicable guidelines. The earth station is a secured location with controlled access.

RADIATION HAZARD STUDY Satellite Education Network Western Illinois University Page 4 of 5 1. Far Field (2.4m Vertex) Rff =0.6 x D / γ = 0.6 x (240cm)² / 2cm = 17280 cm Sff = P x G x 1000 / 4 x π x R² = 74 x 75857.76 x 1000 / 4 x π x 17280² = 1.49 mw/cm² (6.1m Vertex) Rff =0.6 x D / γ = 0.6 x (610cm)² / 2cm = 111630 cm Sff = P x G x 1000 / 4 x π x R² = 155 x 512861 x 1000 / 4 x π x 111630² = .507 mw/cm² 2. Near Field (2.4m Vertex) Rnf = D² / 4 x γ = 240² / 4 x 2 = 30 cm² Snf = 16 x Ef x P / π x D² = 16 x .5 x 74000 / π x 240² = 3.27 mw/cm² (6.1m Vertex) Rnf = D² / 4 x γ = 610² / 4 x 2 = 76 cm² Snf = 16 x Ef x P / π x D² = 16 x .51 x 155250 / π x 610² = 1.08 mw/cm² 3. Reflector Surface (2.4m Vertex) Srs= P / π x R² = 74000 / π x 120² = 1.64 mw/cm² (6.1m Vertex) Srs= P / π x R² = 155250 / π x 305² = .531mw/cm²

RADIATION HAZARD STUDY Satellite Education Network Western Illinois University Page 5 of 5 4. Transition Region (2.4m Vertex) Str= Snf x Sff / R = 3.27 x 1.49 / 120 = .04 mw/cm² (6.1m Vertex) Str= Snf x Sff / R = 1.08 x .507 / 305 = .002 mw/cm² 5. Between Antenna and Rooftop (2.4m Vertex) The bottom of the reflector is 2 meters off the roof. Srt = Srs / % of diameter of antenna = 1.64 / 83 = .02 mw/cm² (6.1m Vertex) The bottom of the reflector is 3 meters from the roof. Srt = Srs / % of diameter of antenna = .531 / 50 = .01 mw/cm² 6. Between Main Reflector and Feed (The highest power level will be at the aperture) (2.4m Vertex) The diameter of the feed is 24cm Sap = P / π x R² = 74000 / π x 12² = 163.58 mw/cm² (6.1m Vertex) The diameter of the feed is 18 cm Sap = P / π x R² = 155250 / π x 9² = 610.09 mw/cm²


Document Created: 2019-04-21 20:42:21
Document Modified: 2019-04-21 20:42:21
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