Montag, 31. Dezember 2012

new 2m Transverter

my as diploma thesis developed transverter got a recent addition to make it useable for S&P work also: a SI570 oscillator bought as kit from SDR kits. Ton, PA0KLT was so kind to produce a special firmware to allow a lower IF (122.6MHz LO to mix 144MHz down to 21.4MHz), where a monolithic quarzfilter filters the RX and TX path. This allows a low-phasenoise output in crowded RF environments like JO60. The normal operation is done with a OCXO (for CQ), but this limits the frequency output to +/-5KHz whats
inside the XTAL fil. The SI570 is not used for CQing, although the output ist quite low in PN and spurs (SFDR > 100dB).
2m transverter blockdiagram

2m transverter frontview with SDR-Kits Si570 LO

top view transverter, lots of filtering inside :-)

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