What Eric says is quite correct. Some of the confusion a few days ago was around the fact that I had completely different issue surface right after installing the hardware mod that suggested it was necessary to upgrade the firmware if the hardware mod is done. That's not true.
The hardware mod simply equips the K3 to handle a faster bus rate that can be selected in the MENU with 3.24 or later firmware. The mod does not interfere with using the original bus rate. The faster bus rate reduces the tuning noise on the K3s tested. Normally, you'll need to remove the antenna or listen on a *very* quiet 6, 10, or 60 meter band to hear the VFO tuning noise. Don't forget there are other potential sources for noise, birdies, etc. Among them are loose/missing case screws (but don't over-tighten them - it doesn't help to make them tighter once they are firmly seated) and cables for the KRX3 subreceiver module not routed per the instructions. The KRX3 manual has details about the cable routing that must be observed for best results. It's worth checking these things if there are any sort of noises or birdies, especially if they seem to have gotten worse or suddenly appeared after working on your K3. One case screw that's often overlooked is on the side of the K3 near the forward end of the handle. It makes sure that side is held securely against the front panel shield inside. Ron AC7AC -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of John Lawrence Sent: Thursday, August 27, 2009 8:08 AM To: elecraft@mailman.qth.net Subject: [Elecraft] One last rehash on tuning hash In answer to Joe Planisky, here's my rehash on hash. My K3 which is factory built still has some tuning hash but it's now at a much lower in level, doesn't move the s-meter (with or without preamp) and is only centered around 28000 +/- 5 KHz. I can barely hear it now. I haven't added the h/w mod. Because this K3 is factory built and never been opened, lets assume it is properly built with cables and fasteners properly positioned and seated. Eric's comment: <<The h/w mod does not really impact the noise at all. It is required though and is there to maintain reliable signaling between the main processor and the synthesizers when the CPU to Synct serial bus speed is increased with SPI=2. Its the change to SPI=2 that reduces the noise.>> I've read some conflicting comments on the need to make the h/w mod. I gather it's Eric's position that it's necessary to keep the signals clean between the main MCU and synthesiszers. Before seeing this latest comment I was left thinking the h/w mod would also further reduce the tuning hash. With all this in mind I can live with small amount of remaining tuning hash. And, this K3 has been running in this configuration for almost a month without any signs of problems that could relate to omitting the h/w part of change. Cheers to the Elecraft team. John, W1QS K3 s/n 2274 K2 s/n 4204 ______________________________________________________________ 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
