16-12-2020, 02:25 PM
FT8 50 Hz Slot Operating Idea.
FT8 by default aligns the TX frequency (audio) to the RX frequency of the station being called. Future transmissions and CQ calls are made on this frequency unless deliberately changed. These will compete with the transmissions of the station just worked. This may result in missed calls due to doubling up of transmissions on the same frequency.
The option of split frequency mode is available but this need to be activated using the "Hold TX Freq" box.
The total bandwidth available for FT8 transmissions for an individual RF frequency is dependent on the receiver bandwidth. This is at least 300 to 2500 Hz but can be higher at 3000 Hz or more depending on the user equipment setting.
Now each FT8 Transmission occupies about 50 Hz bandwidth. Based on the 300 to 2500 Hz bandwidth this gives 44 discrete 50 Hz slots (54 with 300 to 3000 Hz). This is disregarding time slots.
What if each operator operated in the "Hold TX Freq" mode on individual 50 Hz frequency slot (say starting from 300 Hz)? This would mean that some 44 or more operators could transmit at the same time without any frequency transmission conflict. It would be up to each operator to find a suitable 50 Hz slot to suit band activity conditions. With 44 or more slots available this would readily cater for typical 6M DX conditions without the need for doubling up on any 50 Hz slots in most cases.
Any comments?
Igor
VK6ZFG
PS Same concept could also be applies to WSPR with say 10 Hz slots catering for its transmission 6 Hz bandwidth.
FT8 by default aligns the TX frequency (audio) to the RX frequency of the station being called. Future transmissions and CQ calls are made on this frequency unless deliberately changed. These will compete with the transmissions of the station just worked. This may result in missed calls due to doubling up of transmissions on the same frequency.
The option of split frequency mode is available but this need to be activated using the "Hold TX Freq" box.
The total bandwidth available for FT8 transmissions for an individual RF frequency is dependent on the receiver bandwidth. This is at least 300 to 2500 Hz but can be higher at 3000 Hz or more depending on the user equipment setting.
Now each FT8 Transmission occupies about 50 Hz bandwidth. Based on the 300 to 2500 Hz bandwidth this gives 44 discrete 50 Hz slots (54 with 300 to 3000 Hz). This is disregarding time slots.
What if each operator operated in the "Hold TX Freq" mode on individual 50 Hz frequency slot (say starting from 300 Hz)? This would mean that some 44 or more operators could transmit at the same time without any frequency transmission conflict. It would be up to each operator to find a suitable 50 Hz slot to suit band activity conditions. With 44 or more slots available this would readily cater for typical 6M DX conditions without the need for doubling up on any 50 Hz slots in most cases.
Any comments?
Igor
VK6ZFG
PS Same concept could also be applies to WSPR with say 10 Hz slots catering for its transmission 6 Hz bandwidth.