shackspace wiki

for decision, which antenna to use, find answers to the questions:

1. which frequency should be used?
2. omni or directional antenna? radiation pattern: pancake, lobe etc?
3. mounting and drive (az/el rotor and control) ?
4. polarisation of the signals (linear or circular?)
5. required / desired / achievable gain

for amateur radio satellites you would answer these questions e.g.:

1. 430-440 MHz
2. directional antenna with 3.) azimuth and elevation control
3. circular polarisation
4. 12 to 18 dB is required and can be achieved with 1 to 4 20-el X-Yagis

with such antennas you can transmit to the existing hamsats with only 10-50 Watt rf power and you get a good receiver signal

Antenna construction is a very wide field, search the net, especially for ham-radio antennas. Homemadekeing antennas is a nice and low cost occupation. There exists also free simulation software for antennas. Don't ask where exactly, just Google for keywords: Antenna + yagi, beam, turnstyle, lindenblad, elevation, azimuth, circular, polarisation, reflector, dish, patch, stacked array . e.g. http://www.amsat.org/amsat/articles/w6shp/lindy.html