David Space diversity with the K3 is an interesting idea. A variable phase shift could be achieved by adding the raw audio from main rx to a 90degree phase shifted version of itself. Adjusting the relative amplitude of the 90deg version will then vary the resultant phase.
Is a phase shift at audio what's needed here, or is it a delay? I'll let others debate this! 73 Graham On 19:59, David Gilbert wrote: > > John, do any of the SDR programs you mention allow you to monitor the > two audio outputs AFTER the inserted phase shift? > > Here's why I ask, although it is essentially unrelated to a normal SDR > application ... > > I'm convinced that we should be able to use the diversity feature of a > K3 with both receivers to spacially discriminate against an unwanted > signal. We should be able to do it in the horizontal plane by feeding > two vertical antennas into the K3, one into each receiver. We might > be able to partially do it in the vertical plane by, for example, > feeding two stacked antennas on the same tower into the K3 .... one > into each receiver. All we need is a variable phase shift in the > audio since phase is preserved in the conversion from RF to audio. > I've searched for normal audio processing software to accomplish this > (volume equalization, phase shift, inversion, sum), but so far haven't > found anything other than some extremely expensive professional audio > stuff for large auditoriums. > > I've always thought that something like this could be built into the > K3 internal software, maybe using the VFO B knob to adjust the phase. > The K3 phase lock in diversity mode is not determinant (the actual > phase is essentially random at any frequency) so the null would have > to be readjusted at each frequency, but I still think it would be a > neat capability. At one point (more than a year ago) Elecraft sounded > mildly intrigued by the idea when I first suggested it, but I don't > think they've spent any time on it. > > 73, > Dave AB7E ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
