- a closer view of the structure ( 72K ) of the 13.7 m ESSCO dish at the Metsähovi Radio Research Station.
- the pedestal ( 72K ) structure supporting this big antenna
- rear of Cassegrain fed dish with feed support ( 79K ), note TWT with rig on top, LNA and feed horn are behind this.
- the control table that turned into an operating shack ( 73K ), tracking offsets were in the order of thousands of a degree !!!
The rig was a local oscillator affair with separate LO's for TX and RX. The control box visible on the shack table holds the separate frequency tuning ( the two ten-turn pots ) of the LO's ( dual VFO operation on 10 GHz ! ). The LNA had a noise figure of about 4 dB's and fed a 3 dB hybrid mixer with two Schottky diodes.Tthe Hughes TWT managed to feed about 7 W of RF after the transfer relay and necessary coax lines. The rig was built by OH3CU ( OH2MCU nowadays ) and OH3MA.
Own echoes were copied on the first occasion, but I4BER was not QRV yet then. On the second attempt I4BER copied his own echoes FB in Bologna with the University 32 m dish. Goliardo could copy his own echoes on SSB with only about 200 mW of RF with this antenna. On this second attempt the OH2TI team had reception problems and could not copy own echoes or I4BER's either. Our team ran out of time at this end and the rest is history: the Americans beat us to it !!! But only just...
The dish was the antenna of the Metsähovi Radio Research Station back then and our local support there was OH6EH, nowadays a well known radio astronomer specializing in Very Long Base Interferometry.
The best part of this story though is that this 13.7 m dish is now the property of our amateur experimental and research group, the Artjärvi Telecommunications Society, OH2MOH !!!
It will certainly take a while to get this Meccano kit up and running though, but we are working hard on it ;-)
