> > > The roofing filter may have a fair amount of group delay inequality at > the edges of the passband, which can lead to inter-symbol interference > on digital modes. I
WSJT-X can run split. In split mode, it will adjust the Tx frequency so that the audio tones are always near the middle of the the passband. -ch 73 de AI6KG On Mon, Nov 13, 2017 at 3:01 PM, Richard Lamont <rich...@lamont.me.uk> wrote: > On 13/11/17 20:18, Jim Brown wrote: > > On 11/13/2017 11:12 AM, Gary Smith wrote: > >> For those using WSJT-X, sometimes I find > >> the K3s is locked as transmit but there is > >> no RF being sent and no Rx from the K3. > > > > I've been using WSJT-X since it was first introduced several years ago, > > and I've never had this problem. I've always used VOX to put the rig in > > TX mode, as I do with SSB and all digital modes. I've often run with a > > power amp that uses a vacuum relay for T/R switching, and there's > > sufficient delay within the K3 and K3s for the amp's T/R relay to switch. > > You may be putting the performance of your station at a disadvantage > with that approach, compared to using WSJT-X with CAT to keep TX audio > in the range 1500-2000 Hz. > > The roofing filter may have a fair amount of group delay inequality at > the edges of the passband, which can lead to inter-symbol interference > on digital modes. I don't know how serious, if at all, this is in > practice, but I know one very clever engineer who regards it as enough > of a problem to have had a custom roofing filter manufactured for his K3 > to reduce it. He mainly works EME with JT65. > > > 73, > Richard G4DYA > ______________________________________________________________ > 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 c...@murgatroid.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
