On Nov 27, 2010, at 11/27 5:14 AM, Joe Subich, W4TV wrote: > MixW has a dual [RTTY] receive capability - I don't know about any > of the other software.
On the Mac OS X side, cocoaModem has two independent receive channels in the "wideband RTTY" and the "dual RTTY" interfaces. There are two identical sets of user interfaces in a single window -- this gets rid of the "window focus" problem of running multiple copies of a software modem. There are two cross ellipses, independent mark and space tones, baud rate, and filter settings -- you can even run 75 baud and Mark-only on one decoder, while running 45.45 baud and Mark/Space decoding on the other. In the case of "wideband RTTY," there are independent waterfalls. Dual RTTY decode has been in practice in some time now. In the old days, it was done with multiple TU -- this is one of the reasons why normally sane people have multiple HAL ST-8000 in the shack. Just like other modes, having concurrent receive capability on on both the DX and a split pile reduces "doubling." Using multiple TU back then required manually scanning the pileup using the VFO knob. If you have a waterfall that is watching the pile, you can pretty much pinpoint the DX's QSX by watching where a signal appears in the pileup waterfall right after the DX finishes sending his exchange. A software modem that is capable of agile transmit can then pounce on that QSX (or find the next hole in the direction the DX is tuning). It used to be like shooting fish in a barrel for people with two RTTY decoders and agile receive (e.g., waterfall tuning) to work the split RTTY pileups. Just ask RTTY DXers who have been using cocoaModem's "wideband RTTY" interface. But more people have that capability today (what with the Flex-5000 and the LP-PAN), to the point that if you don't have dual decoding and agile tuning capability, you are now at a distinct disadvantage. Of course you need a sound card that has two or more inputs (or a digital interface like the microKeyer/digiKeyer). Some of the cheaper digital interfaces are only wired for a single input channel, even when the codec is a stereo one. 73 Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
