While I was making some tests on Tx carrier suppression I figured out the presence of a very weak cw signal at the output of the 100W PA. This signal is exactly at the operating frequency the VFO indicates. It exists every time you key the transmitter even with the Tx audio cables disconnected, so it is produced inside the SDR-1000 box. With power set at 100 on PowerSdr the amplitude of the signal varies from -20 dbm @ 160 m to 0 dbm @ 10 m. As far as I know on Rx the DC frequency is located 11.025 kHz below VFO and during transmit shifts to the VFO, so I suppose that this signal somehow originates from FT3253 switch noise. I want to ask if someone else has noticed the same behavior and if the figures I measured are normal.
73 Christos, sv1fxo _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
