CTCSS on AO-51 disabled
The transponder on the AO-51 no longer requires presence 67 Hz CTCSS suton in the modulation of the transmitting station. For operation, it is enough to transmit a clear FM signal on a 2m uplink.
The CTCSS system was supposed to save on-board batteries. In the areas, where there is interference at the uplink frequency, the transponder would be activated unnecessarily. However, the use of CTCSS caused modulation outages and made it more difficult to work through AO-51.
Through the AO-51 it is also possible to work with a dual-band handheld FM station, provided that profitable antennas are used. On the downlink, however, I still highly recommend the preamplifier.