On 20 Feb 2000 a 10 GHz FM ATV test
transmission was made by Jose VK3TMS from Mt Macedon to Geoff
VK3GE (ex VK3JDG) in Sydenham, a distance of approximately 43 Km.
VK3TMS transmitted using 10 mW from a gunn diode with a small horn
feed into a 60cm offset TVRO dish. Video was processed and fed to a
varactor diode placed near the gunn diode. Problems were experienced
with the video quality during the test as the transmitter head had
fallen against some metal work in the rear of the transport vehicle on
the way up the hill and along a very bumpy dirt road. With tolerances
being very small at 10 GHz this had the effect of altering things to
the point of upsetting the alignment between varactor and gunn diodes.
The receive system was set up on the veranda roof at the QTH of
VK3GE (ex VK3JDG) in Sydenham, which gave good views of Mt Macedon ( see photo
below ). Receive consisted of a modified Ku TVRO LNC fed from a 60 cm
prime focus terrestrial dish with a penny feed at the focal point. The
I.F. out of the LNC was fed to a standard satellite receiver to
produce composite video.
No audio was transmitted on 10 GHz. Actual frequency used was
10.360 GHz with 10 mW on the TX end and approx 30db of gain in the
dish's at each end. Signal strengths received were approx 25db above
the noise. The width of the transmission beam caused a few problems
for alignment as a movement of either dish 1.5 to 2 degree's in any
direction would cause the signal to drop into the noise. The received
video was retransmitted to the VK3RTV repeater on 1250 MHz for all to
see. Liaison was on 147.400 MHz FM.
For any enquiries or for further information please send an email
to either Jose VK3TMS or Geoff
VK3GE