The basic idea is to use a mor or less fixed IF 1296MHz. Tunability is some +/- 4MHz within -3dB of the IF bandpass filter. Local oscillator is on high side of signal frequency, hence ”reversed tuning”. LO is generated with a Racal-Dana 3102 synth and multiplied with G8ACE multipliers. Reason for this is to use already existing and available designs when possible hence the choise of a close to 10GHz multiplier chain.