KX3’s LO noise figures are some of the best out there and I’ve seen no reports of such a problem (even a degradation of 20-30dB would still put it above many current radios). Maybe you are referring to the VFO tuning noise ?
Razvan.
I guess, you are mentioning the issue of devices with low serial numbers, which could be overcome by this modification : http://www.elecraft.com/manual/KX3%20Tuning%20Noise%20Mod%20rev%20B3.pdf
Of course, that’s the price early birds have to pay 
Hopefully elecraft is not repeating the same learning curve again with their newer radios.
This explicitly refers to 10m. It is not applicable to the overall performance of the LO. Incidentally that “zipper” noise mod is related to the filter module being present. On mine that is not installed, yet I can still detect the presence of tuning noise on 10m specifically.
If you read performance data from, lets say the Sherwood list particularly on phase noise. This does not infer anything about the performance of the radio on other parts of its usable spectrum, just where it was measured and the measurement bandwidth. This is specific to the DUT. How you attach words such as “flawless” and “best out there” is of your own accord. They are mere qualitative statements, not quantitative measurement data.
I believe the low level “zipper” noise on mine is caused by the phase update/accumulate registers in the Local Oscillator being delayed, its a “feature” of the Si570 tuning word length that makes fast tuning difficult to achieve without the output of the synthesizer being pulsed or reset in some way. On a personal note it annoys me, It is very weak on 10m, but its there even with an antenna connected. My example is in the 6xxx series of serial numbers, it is not an early release.
It is a lovely piece of kit in many ways, I do get pleasure from using mine. However it is certainly not flawless. Nothing is, I am sure the new IC7300 will have its problems too.
Jonathan
Hi Everyone-
Just a note to let you know the KX2 is on the Elecraft website and showing “in stock”.
Best,
Rob
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QQ, does this permit use of UK 5MHz bands without “wide banding” (if you can do such a thing)?
Found this on the manual, 5.3-5.4 MHz shared with other services. When I purchased my KX3 in the UK it had the same restrictions but after talking to elecraft I was able to unlock it but lost the CB band, once the kx3 is unlocked there is no going back.
Would love a KX2 myself but knowing my luck a Ft817 replacement would come out after a purchase.
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If you try really hard and search for it, you can find the band unlocking software on a internet forum. The software is designed for use with the K3, but also works with the KX3, as it uses a similar MCU system.
I think you can restore the band limits. I personally don’t use 11m, I cannot confirm that.
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