Thanks for the explanation. The band pass filters add an interesting consideration to multi-band use.
Sent from my iPhone > On Aug 20, 2019, at 8:27 AM, Wayne Burdick <n...@elecraft.com> wrote: > > This will work with either a K4 or a K4D. The VFOs can be on the same or > different bands. > > If the two receivers were on different bands, and you only had one antenna, > you'd want to make VFO A the higher-frequency band. This is because with a > single antenna, both receivers would be sharing the transmit signal path, > which includes low-pass filters. > > Suppose VFO A is on 20 meters and VFO B is on 40 meters. Both are subject to > the 20 meter low-pass filter, so both will have full sensitivity. Now you > want to work a station heard on 40 meters (VFO B/sub). Since you need the 40 > meter low-pass filter for transmit, you'd the controlling computer would need > to swap VFOs (or you could do this manually by tapping A/B). > > * * * > > Notes: > > - If you had a separate receiving antenna usable on multiple bands, then the > low-pass filter constraint goes away; either VFO could be on any band. You'd > still need to swap VFOs to transmit on the VFO B band, then swap back. > > - If you had a K4D, then each receiver would have its own set of bandpass > filters, which may be helpful in high-signal conditions. They could also use > different antennas. > > - It may even be possible to run WSJT on the K4 itself, though I can't put a > date on this. Some porting required :) > > 73, > Wayne > N6KR > > > >> On Aug 19, 2019, at 11:06 PM, Logan R Zintsmaster <lra...@garlic.com> wrote: >> >> Here is a use case question.. >> >> The radio is connected to a single antenna. >> >> VFO A is tuned to 14.074 MHz and VFO B is tuned to 14.080. >> >> An audio data stream from the VFO A frequency is "connected" to an instance >> of WSJT-X decoding FT8. >> >> A second, independent audio stream from the VFO B frequency is concurrently >> "connected" to a second instance of WSJT-X decoding FT4. >> >> Both instances of WSJT-X decode their respective audio streams, >> concurrently. >> >> Starting a QSO in either instance of WSJT-X switches the transmitter to the >> appropriate VFO for the duration of the QSO. >> >> The audio stream for the instance of WSJT-X not in the QSO is interrupted >> while the transmitter is operating. >> >> >> >> Can a K4 support this use case or is a K4D required? >> >> Can this use case be supported if each instance of WSJT-X is in a different >> band? >> >> >> >> 73 >> >> Logan, KE7AZ >> >> >> >> >> >> ______________________________________________________________ >> 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 >> Message delivered to n...@elecraft.com > ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
