I don't believe that a claim that T/R turn around time limited by relay switching is valid for a PowerSDR driven radio. Maybe the hardware will turn around that fast, but the software latency IS a major part of SYSTEM T/R turn around. T/R turn around from the QSK standpoint includes the RX latency ( 10's of millsec to 100 + millisec, depending on sample rate and buffer sizes ) + TX latency ( ?? millsec ) + hardware ( 5 millisec ?? ) . Even though the RX DSP may be full duplex, you can't began to process a RX signal until the TX signal drops to zero and then you will not HEAR anything usable until after the RX latency !
System T/R turn around is hardware KEY UP to NEW SOUND in the ear.. CW inter-character (inter-word) gap is how many millsec. ?? Disclaimer: I'm not a CW op and I love my SDR. Al, K0VM P.S. The RX latency on my analog radio is < 10 millsec. > Date: Thu, 24 Apr 2008 01:00:12 +0000 > From: Dave Blaschke <[EMAIL PROTECTED]> > Subject: [Flexradio] CW QSK ability > To: flexradio@flex-radio.biz > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > I quote from the Flex web site: > > "T/R turn around times are limited only by the transmit relay delay > with a mean turn-on time of an unbelievable 2.5 ms and a turn-off > time of 1.5 ms" > > How do I obtain this performance with my SDR-5000? As I adjust > Delay(ms) on the front panel of PowerSDR it only allows me to go as > low as 10 ms. Is there something I am missing, or is this not an > accurate T/R turn around value? > > I believe that the limited QSK capability of PowerSDR/SDR-5000 has > been its chief (and perhaps only) weakness on CW. My old FT1000D > handles QSK much more smoothly and rapidly. Perhaps SDR radios, by > their very nature, cannot be expected to match such performance. If > I could obtain the T/R turn around time stated in the quote above, > this problem is solved. But how do I do it? > > Dave, W5UN _______________________________________________ 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/
