Using equipment seen in my earlier posts a 2 way NB DATV contact was completed on 12-01-14. My QSO with Arthur G4CPE was over a fairly short path; some 4.65 Kilometres.
During our contact powers as low as 200mW were used and signals remained solid throughout. Transmission mode was MPEG-2 at 543kS/s, and the QPSK encoder is a Link Research device with output at 70MHz. My DDS generates 216.500MHz and the two signals are mixed to 146.500Mhz and filtered before amplification by the PA.
Initial transmissions were carried out using collinear antennas. Over the next few day we will be carrying out various tests including some using horizontal polarisation.
Acknowledgements to Arthur G4CPE who supplied some of the components including a complete receive converter and lots of technical guidance. Thanks.