We report the development of solar flux receivers operating at 2.8 GHz to monitor solar radio activity. Radio waves from the sun are amplified, filtered, and then transmitted to a power meter sensor without frequency down-conversion. To measure solar flux, a calibration scheme is designed with a noise source, an ambient load, and a hot load at 100℃. The receiver is attached to a 1.8 m parabolic antenna in Icheon, owned by National Radio Research Agency, and observation is being conducted during day time on a daily basis. We compare the solar fluxes measured for last seven months with solar fluxes obtained by DRAO in Penticton, Canada, and by the Hiraiso solar observatory in Japan, and finally establish equations to convert observed flux to the so-called Penticton flux with an accuracy better than 3.2 sfu.

Abstract
1. INTRODUCTION
2. DESIGN AND FABRICATION
    2.1. General
    2.2. Noise Source and Temperature Sensor
    2.3. Fabrication
3. CALIBRATION
    3.1. Formulation
    3.2. Measurement of Noise Power
4. SOFTWARE
    4.1. General
    4.2. Microcontroller Unit
5. OBSERVATION
6. COMPARISON WITH PENTICTON AND HIRAISO SOLAR FLUXES
7. CONCLUSION
REFERENCES

• YOUNGJOO YUN(Korea Astronomy and Space Science Institute)
• YONG-SUN PARK(Department of Physics and Astronomy, Seoul National University) CORRESPONDING AUTHOR
• CHANG-HEE KIM(Department of Physics and Astronomy, Seoul National University)
• BANGWON LEE(Department of Physics and Astronomy, Seoul National University)
• JUNG-HOON KIM(Space and Earth Technology System)
• SAEHO YOO(Space and Earth Technology System)
• CHUL-HWAN LEE(Space and Earth Technology System)
• JINWOOK HAN(Korean Space Weather Center, National Radio Research Agency)
• YOUNG YUN KIM(Korean Space Weather Center, National Radio Research Agency)