Hi Ron, > Eric and my statements are quite correct, both of them!
OK, I'm really missing something then. Eric said (emphasis mine): > There is no downside to making this h/w mod, EVEN IF YOU DO NOT > ENABLE THE MENU OPTION. That sounds very much like he's saying you can make the mod and not change the SPI bus clock rate to SP2. But you just said (again, emphasis mine): > If you add the diodes and resistors per the App Note, ... YOU *MUST* > CHANGE THE SPI BUS CLOCK RATE TO "SP2" FOR PROPER (STABLE) OPERATION. I don't see how they can both be correct. The reason I would like clarification is that I sometimes go back to a previous FW release to compare operation with the new release. If what you say is true, that implies that once I make the hardware mod I can't go back to the 3.19 release without potentially having VFO stability issues. If that's really and truly the case, I don't want to do the mod until I'm sure I won't ever want to go back to anything older than 3.24. 73 -- Joe KB8AP On Aug 23, 2009, at 7:05 PM, 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: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] 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:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
