Thanks for that information, Ed. While the LO frequency remains constant, the two LOs will be locked in phase so the RF signal streams will be locked in phase as well. The relative phase may be arbitrary, depending on exactly how the two separate sets of synthesizer tuning instructions were loaded and then executed, but MAP65 will probably factor out any fixed phase differences.
73 from Ian GM3SEK >-----Original Message----- >From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of >Edward R Cole >Sent: 18 January 2015 19:13 >To: Elecraft@mailman.qth.net >Subject: Re: [Elecraft] Diversity reception in the K3 > >Ian, > >My impression is that the two received signals are in phase-lock at >the first IF before the roofing filters. I export both IF outputs to >a pair of LP-Pan that are run by one xtal oscillator so their >baseband IQ outputs are locked in phase for use in my adaptive >dual-pol receiving system (using MAP65 sw). > >With two phase-locked IQ streams polarity angle information can be >determined by special sw routines that compare the relative amplitude >of two orthogonally polarized signals. I use this for 2m-eme but it >could be used with any two orthogonally polarized antennas (eg on HF: >to horz dipoles at right angles to each other). > >73, Ed - KL7UW >http://www.kl7uw.com/MAP65.htm > >---------- >From: "Ian White" <gm3...@ifwtech.co.uk> >To: "'DaleJ'" <dal...@mac.com>, <Elecraft@mailman.qth.net> >Subject: Re: [Elecraft] Diversity reception in the K3 >Message-ID: <003001d0331d$2016aed0$60440c70$@co.uk> >Content-Type: text/plain; charset="us-ascii" > > >The frequencies of the two receivers in the K3 are locked together for >diversity by sending identical instructions to the two identical >synthesizers which also share the same clock oscillator. > >RF phase doesn't need to be coherent for diversity reception as >implemented in the K3, because the two signals are only combined at >audio frequency (usually between the operator's ears). There may be >small difference in time delay (group delay) through the roofing filters >in the two receivers but in practice this doesn't seem to be a problem. > > >73 from Ian GM3SEK > > >73, Ed - KL7UW >http://www.kl7uw.com > "Kits made by KL7UW" >Dubus Mag business: > dubus...@gmail.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
