Transmitting Oscar 100 DATV signals

To transmit DATV signals on Oscar 100 you need to be able to generate DVB-S2 signals on ~2400 MHz. This page outlines some possible transmit systems.

For a full guide to transmitting on Oscar100 see CQ-TV 263.

DATV transmit systems

To transmit DATV on Oscar 100 you will need a system to generate DVB S or DVB-S2 (preffered) on 2400MHz.

Systems include:

Portsdown system

The BATC Portsdown 2019 system using the LimeSDR mini

Dish size and power required

There are 3 key variables: dish size, power and symbol rate. The power received at the satellite varies with the square of the dish diameter, so for example a 1.2m dish will give 4 times the amount of power (6 dB more) than a 60 cm dish. The power density in terms of frequency will vary inversely proportional to the symbol rate. So a 250 KS signal will deliver double the power density (watts per MHz) at the satellite compared to a 500 KS signal of the same transmitted power.

Based on observed performance of the transponder, this table gives the power required and dish size to achieve the same level as the beacon at 250 KS:

To see the full article, including how the power required varies with symbol rate and lower MER, see C-TV 263 - available for download here https://batc.org.uk/cq-tv/cq-tv-download/