These are some experimental antennas for AO-40. They are not optimal antennas but all of then are capable and will enable mode S reception.
See also my new AO-40 Deck Receiving system.
Portable DSS Offset Dish
Portable (tabletop) antenna for AMSAT OSCAR 40 Mode S. The antenna is a small TVRO offset dish iluminated with a 2.5 turn helix (see below). Dish major axis is 53.5 cm (21.0") and minor 47.0 cm (18.5"). Converter is SSB UEK-2000 and receiver is a vintage Yaesu FT-221R. Antenna and converter are mounted on a photographic tripod. This combo (dish + converter) provides acceptable reception of the S2 downlink at apogee (60,000 plus Km range)
28 Turn Helix
Details of the 28 Turn Helix. This antenna is based on an AF9Y original desing for 435 MHz (I also made the original 435 MHz version) and scaled to 2.4 GHz by K5OE. Altough I do not recommend this antenna for routine usage is very easy to make and has a very convenient size for portable use. Note that I made my first AO-40 QSOs with this antenna and the SSB UEK-2000 converter.
Copyright © 2001 Antonio Fernández