Callisto at the University of Pune/India operational

Installation of a new Callisto at Pune University in India between 23th and 25th of November 2011 during a Solar Radio Workshop dedicated to Callisto and e-Callisto network. During the workshop two other groups from Ahmedabad/India and Sri Lanka learned how to install and configure a Callisto system. S. Ananthakrishnan (Pune) and Rajamal Jain (Ahmedabad) studying the new log-per on the roof of the institute of electronic science. The preamplifier is close to the top of the antenna to get full sensitivity. The antenna, a special design covering 100 MHz - 1000 MHz is pointing to an average position of the sun during transit.
And we already got a first light on Nov. 23th at 08:47 UTC. It shows the first harmonic of a low frequency type II solar radio burst.

Callisto operational in Simpheropol, Crimea

Antenna used for e-CALLISTO is a synphased array of 16 elements (4x4) with total size of 3.5x3.5 meter. Every Yagi consists of 7 dipoles. The frequency range is 250-350 MHz, the beam pattern is of the order of 11^o. Aerial is set on a parallactic mount with an electric drive for tracking the sun from 5 UT up to 13 UT.

The antenna is connected with a CALLISTO spectrometer (placed in a laboratory room) through out a preamplifier ZX60-33LN+ having a gain of 20 dB (placed in antenna box) and through 40 meters of coaxial cable (total losses 4 dB). The sensitivity of the equipment is good enough for the observation of quite sun level.

A construction of new antenna with bigger frequency range is planned in future.

Photo: courtesy: Aleksandr Volvach, Radio Astronomy of Crimean Astrophysical Observatory, Ukraine.

Callisto Helwan University Cairo, Egypt

Installation of a large log-per at Space Weather Monitoring Center at Helwan University south of Cairo, Egypt.
The antenna covers 20 MHz up to about 175 MHz. A MiniCircuits preamplifier is just below the antenna enclosed in a metal box.

S-Band spectrometer based on Callisto

Below 1 GHz local interference (rfi) is too high to get acceptable data quality. Therefore I decided to go higher in frequency into S-band. A cheap WiFi antenna is pointing to the meridian position of the sun and the rf-signal is down-converted by a heterodyne converter (eBay) into the base band of Callisto. With this configuration it should even be possible to measure quiet sun flux...

Input reflection coefficient Callisto

s11 over the whole frequency range of Callisto is always < 10dB. Philips specifications guarantees 8dB. So this instrument is o.k. in terms of input reflection.

Basic schematic Callisto

Callisto is a double heterodyne receiver with two IF, first at 37.7 MHz and 2nd at 10.7 MHz.
RF- and IF-gain are controlled by a PWM-signal via ATmega16. Detector is a logarithmic AD8307.
Tuner is Philips CD1316x, where x denotes to different versions.
Callisto is connected via RS232 (115 kbit 8N1) to a standard PC running on Windows 98, 2000, XP or 7. Third party software for Linux can be found on my instrument website.

How to solve the problem of cross modulation caused by FM transmitters

A simple and cheap solution to get rid of strong FM signals. The basic prinziple can also be applied to any other frequency range.

e-callisto.com/GeneralDocuments/Microsoft Word - Crossmodulation in Callisto systems caused by strong FM.pdf