[Elecraft] K3 VFO tuning hash

[John Lawrence]

Wayne

Sorry to bother you on your vacation.  Yes, thirty years of trying to get away without leaving the connections to business behind is well known to me.

Let me put a cap on this for now by saying there are other chaps out there with the same issue and there’s one who hears a saw like sounds while tuning on six meters and it reminds me of my issue on 10 meters.  I understand from some that you've been made aware of the findings consistant with my K3 serial number 2274.  

With increased fine frequency tuning the number of step clicks increases per unit of frequency change.  As I see it this means that the noise is being generated after the encoder’s frequency divider function.  It’s not coming from the raw optical encoding device on the VFO and RIT tuning knobs.

The amount of this stepping noise isn’t just above threshold.  It’s more noticeable than that and was heard over the telephone by your tech support member who received my call two weeks ago.


Enough said for now.  Sorry enjoy your vacation.

73,

John, W1QS







73,

John, W1QS


On Jun 28, 2009, n6kr at elecraft.com wrote: 
John,

I've noted your report of VFO tuning noise on 10 m, and will look into  
it further when I get back from vacation. Sounds like re-radiation of  
SPI bus tuning data, and this could be frequency specific. It might  
also vary with the type of antenna, ground, and other I/O devices  
connected to the rig. Usually atmospheric noise masks any digital  
switching noise, which is typically at an extremely low level.

As Graham noted, a temporary workaround might be to use the DSP noise  
blanker, set to something like t1-5. This will have virtually no  
impact on normal signals, and is applied post-crystal filter so it  
can't cause wideband IMD. The DSP NB is quite good at removing low- 
level, high rise-time signals. NB settings are stored per-band, and  
you can also save the on/off status on a per-band basis by setting  
CONFIG:NB SAVE to YES.

73,
Wayne
N6KR


> On Jun 27, 2009, g3tct at lineone.net wrote:

> This noise was previously reported under the title "K3 Tuning  
> encoder pulses and birdie problem"
> In my case it is only noticeable at the low end of 28MHz when there  
> is a low noise level from the antenna or with a dummy load attached.

> Wayne suggested using the noise blanker on a low setting like t1-5,  
> also tightening screws and tmp cables may help.  In my case it  
> seemed to get better when I installed the KRX3, but maybe cos I  
> tightened up the screws and cables.
> HTH
> Graham