[Elecraft] K3 VFO tuning hash
Wayne Burdick
n6kr at elecraft.com
Sun Jun 28 02:55:16 EDT 2009
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
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