K3 VFO tuning hash

[john lawrence-3]

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, [hidden email] 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, [hidden email] 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


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[K7TV]

If you worked W7MOT on either 15 or 40, you worked my K3. The operators
using the K3 seemed very pleased with it. All who heard the diversity
reception agreed that it is a valuable resource for copying in the face of
QSB. For a second receive antenna we used a BuddiPole configured as
vertical, tuned very roughtly to 15 without coil, and with a wire
counterpoise. This provided sufficient receive signal on 40 as well as 15,
with the subreceiver at full RF gain and the main receiver RF gain backed
off.

Within the overall success of K3 operation a few glitches were observed.

With diversity reception on I tried to demonstrate the cw tuning aid. No
indication of received signal frequency was displayed (nothing to show that
the received pitch was either on frequency or off). This may have been
operator error, and in the rush for contest points I had no time to research
or experiment. Anyway, the expected display was seen, minus the black mark
that normally shows the received signal pitch relative to the expected
pitch.
I was running the latest official firmware release for the contest. I
apologize for mentioning this without first investigating the conditions
under which the problem may be repeatable, but, well, I am tired from
operating late in the night...

Operating CW using N1MM with LP-PAN and LP-Bridge and WinKeyer, 3 times
during the contest I saw the mode unexpectedly change from CW to LSB at the
time of transmitting. Although this had no negative impact on the contesting
operation (just puch the mode control to recover), next year we obviously
need to take some steps to reduce stray RF around the radio and computer. I
have never had any such problem with the same setup at home, where the
antennas are farther away.

Our best CW operator voiced some slight disappointment that the setup did
not produce the booming low-frequency notes of off-frequency CW signals that
he favors. I have to agree that it is easier to distinguish between
different stations when the pitch is low. Maybe I will ask Elecraft for the
mod that I have seen mentioned that allows receive audio at lower
frequencies. (Off the top of my head, I think it has been said on the list
that the cutoff is 200 Hz.)

73,
Erik K7TV



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[Brett Howard]

You may have had the CW decoding threshold set to high...

On Sun, 2009-06-28 at 20:37 -0700, Erik N Basilier wrote:

> rsity reception on I tried to demonstrate the cw tuning aid. No
> indication of received signal frequency was displayed (nothing to show
> that
> the received pitch was either on frequency or off). This may have
> been
> operator error, and in the rush for contest points I had no time to
> research
> or experiment. Anyway, the expected display was seen, minus the black
> mark
> that normally shows the received signal pitch relative to the
> expected
> pitch.
> I was running the latest official firmware release for the contest. I
> apologize for mentioning this without first investigating the
> conditions
> under which the problem may be repeatable, but, well, I am tired from
> operating late in the night...

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