Yes, thank you Matt for the explanation. I obviously didn't think it through as well as I should have.
- Brendon KK6AYI On Fri, Oct 7, 2016 at 12:22 PM, Matt Maguire <[email protected]> wrote: > Hi Brendon, > > In a way you are right, but consider this: the per-band nulling procedure > is to compensate for amplitude and phase variations introduced in the LO > and quad mixer which can be different from band to band. However, when you > put a roofing filter in the signalling path, it will introduce a further > amplitude and phase imbalance (which as you say will be the same for all > bands). The per-band nulling parameters you set up before adding the > roofing filter will all need to be adjusted to take the impact of the > roofing filter into account. This is why you should repeat the whole > nulling calibration for each band when you add a roofing filter. Does this > make any sense? > > 73, Matt VK2RQ > > _____________________________ > From: Brendon Whateley <[email protected]> > Sent: Saturday, October 8, 2016 3:00 am > Subject: Re: [Elecraft] Soon to be an Elecraft(er)! > To: Matt Maguire <[email protected]> > Cc: Elecraft Reflector Reflector <[email protected]>, Ray Sills < > [email protected]> > > > > Given my understanding of the roofing filter design in the KX3, I don't > think there is any per-band adjustments to make. IIRC, the filter is an > analog low-pass filter that operates after the direct down-conversion. > > If I'm wrong, then please set me straight. Especially because I'm > considering adding the filter to my KX3. > > - Brendon > > On Thu, Oct 6, 2016 at 11:35 PM, Matt Maguire <[email protected]> > wrote: > >> Does the factory do a full per-band calibration, or do they just >> calibrate on 20m and extrapolate? If the latter I'd suggest to do the full >> per-band calibration yourself even for a factory-fitted roofing filter, as >> it does make a difference (obviously back up your config first so you can >> restore to factory settings/calibration if needed) >> >> 73, Matt VK2RQ >> >> >> >> >> On Fri, Oct 7, 2016 at 5:38 AM +1100, "Ray Sills" <[email protected]> >> wrote: >> >> >> >> >> >> >> >> >> >> >> Also, IF you order the roofing filter for the KX3…. even with a kit >> purchase…. the factory will calibrate it for you, so all you need do is >> install the little board. They have a test jig, so that the filter will be >> tested with YOUR particular main board. Best of both worlds… save some >> money, and get free factory calibration. >> >> 73 de Ray >> K2ULR >> KX3 #211 >> >> >> > On Oct 6, 2016, at 12:00 PM, Walter Underwood wrote: >> > >> > The roofing filters require some calibration. If they are >> factory-installed, Elecraft does that for you. All the other options are >> exactly the same whether factory-installed or user-installed. >> > >> > wunder >> > K6WRU >> > Walter Underwood >> > CM87wj >> > http://observer.wunderwood.org/ (my blog) >> >> ______________________________________________________________ >> 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 >> Message delivered to [email protected] >> >> >> >> >> >> ______________________________________________________________ >> 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 >> Message delivered to [email protected] >> > > > > ______________________________________________________________ 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 Message delivered to [email protected]
