On 12/10/2019 05:12 PM, Lukas Haase wrote: > Hi Marcus, > >> Von: "Marcus D. Leech" <patchvonbraun@gmail.com> >> [...] >> You're using the MANUAL policy for BOTH DSP and RF. Let the automatic >> "stuff" do its thing, with the only difference being integer-N tuning. > Pretty incredible, I think I found the(?) issue. > https://kb.ettus.com/UBX#Phase_Synchronization: > > "If you are operating the UBX at frequencies below 1 GHz and need phase synchronization, then it is necessary to select a 20 MHz daughterboard clock rate, instead of using the default 50 MHz rate [...] If you're using GNU Radio, then you can add "dboard_clock_rate=20e6" to the "Device Arguments" field of the properties for the UHD Sink and UHD Source blocks." > > > I did this and lo and behold, the phase stays constant across tunes! > It even works without mode_n=integer most of the time ... I think sometimes I get the frequency shift I was mentioning in a previous message. > With mode_n=integer it works for all frequencies I have tried. I really hope I did not miss anything. > > Well, that is something I did not know, although perhaps I should have. Hard to keep *everything* in my brain about all the various bits of hardware Ettus has released in the last few years... Please let us know if there's anything *else* that crops up...