I apologize, but Ron is incorrect. You MAY make the diode/resistor termination mod without changing the but timing in the menu. It has no negative impact in eother case.
73, Eric WA6HHQ ==== Ron D'Eau Claire wrote: > Eric and my statements are quite correct, both of them! > > If you add the diodes and resistors per the App Note, which provide better > termination on the synthesizer control lines, you *must* change the SPI bus > clock rate to "SP2" for proper (stable) operation. > > V 3.24 (or later) firmware has a menu command that allows you to change the > SPI bus clock rate as needed. > > The K3 works perfectly with that change, but with much reduced noise while > turning the VFO on the 6, 10 and 60 meter bands, at least for those who > experienced the noise. > > A few people have downloaded the newer firmware (3.24 or later) and tried > changing the SPI clock rate without installing the diodes and resistors that > terminate the synthesizer control lines. Doing that leads to unstable > operation. > > Similarly, I installed the diodes and resistors (while illustrating the App > Note), forgot to change the SPI clock rate, and found my VFO unstable. > > After some head-scratching I realized my oversight, changed the SPI bus > clock rate to "SPI 2" and everything is perfect again. > > So the K3 is perfectly stable without installing the parts, no matter which > version of the firmware you install, provided you leave the menu command for > the SPI Bus rate at CONFIG:MD SPI 1. > > Similarly the K3 is perfectly stable with the diodes and resistors > terminating the synthesizer control lines provided you change the SPI bus > rate to CONFIG:MD SPI 2 > > Ron AC7AC > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Joe Planisky > Sent: Sunday, August 23, 2009 6:24 PM > To: Elecraft Reflector > Subject: Re: [Elecraft] K3 Hardware Updates > > Now doggonnit, let's get our stories straight! > > Ron D'Eau Claire says: > > >> ... if you add the resistors and diodes and do not >> change the timing, the VFO may become unstable, >> > > Eric Swartz says: > > >> There is no downside to making this h/w mod, even if you do not enable >> the menu option. >> > > Am I missing something, or are these two statements contradictory? > Maybe Wayne can be the tie-breaker :-) > > 73 > -- > Joe KB8AP > > > > On Aug 23, 2009, at 4:08 PM, Ron D'Eau Claire wrote: > > >> Well, it shouldn't hurt to do the mod, but I agree with David if you >> can't >> find any noise. >> >> The reason 3.24 is required is that it provides a menu entry for >> changing >> the bus timing as described in the procedure. A slightly different >> timing is >> required for stable operation once the diodes and resistors are added. >> >> If you try to load the firmware and change timing without adding the >> resistors and diodes, or if you add the resistors and diodes and do >> not >> change the timing, the VFO may become unstable, making un-commanded >> QSYs. >> (On my K3 they were in 100 Hz steps.) >> >> The default timing in all the firmware, including 3.24 and up, is >> correct >> for K3's that do not have the diodes and resistors added, so you >> need do >> nothing after upgrading your firmware if you haven't added the >> parts. Your >> K3 will continue to work FB just as always. >> >> A revised mod procedure will be posted Monday to make that point >> clear. >> >> Ron AC7AC >> >> > > ______________________________________________________________ > 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 > > ______________________________________________________________ > 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 > -- _..._ ______________________________________________________________ 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
