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 :-)

Sonntag, 30. Dezember 2012

networked logging with win-test (WT-Tunnel)

Well, in SO2R contests you can at least let a CQ run (which never results in a high rate with low power), and do some S&P in parallel. If you have access to a remote site in 2km diameter, like me, you can do this on the same band,if the TRXs are good enough decoupled. For now you can download the "wt-tunnel" software to connect 2 Win-Tests via Inet together. You need