Happy Birthday, AO-7!
It's just thirty-five years old, čo bol satelit AO-7 vynesený na obežnú dráhu. Delta shuttle 2310 ho vyniesol 15.November 1974 spolu so satelitmi ITOS-G (NOAA 4) a španielskym INTASAT-om.
For operation in mode B (uplink 432,125 – 175 MHz CW/LSB) a low-power transmitter or transverter is sufficient (approx.1 – 5W). Antennas with circular polarization are particularly suitable, but it is not a condition. The signal itself should be so strong, so as not to overload the transponder. Recognize this by distorting the downlink signal.
The downlink (145, 975 – 925 MHz CW / USB - pay attention to signal inversion) it is necessary to have a gain directional antenna (approx. 10 dB). The preamplifier will help a lot, because without it the signals are only S1 - 5, resulting in, that many stations add power to 70cm.
That the AO-7 is in mode B can be recognized by the beacon signal at 145,972 MHz. If he's not there, the transponder is in mode A or is switched off.