I find the K3 NB to be surprisingly effective. I also find that
adjustment is highly dependent on the characteristics of the signal and
the noise, and the effects of changing those adjustments is subtle. The
effect of a blanker on ignition noise was really astounding ... "was,"
because ignition noise seems to be history these days. I suspect that
many of the "it doesn't work very well" observations may stem from
anticipation of a dramatic disappearance of today's noise from
incidental and unintended radiators with NB on. My local noise comes
from the NV Energy power system and an uncountable number of Part 15
violators in the house and neighborhood. K3 NB is very effective for me
against them.
I am a bit sorry that both the IF and DSP blanker parameters are so
cryptic in the K3. Depth of the blanking pulse and width of the
blanking interval are the two "real" parameters involved. The K3 seems
to camouflage them which, for me at least, makes them a bit harder to
adjust properly, I'm not sure what I'm doing when I change them.
Incidentally, punching holes in the receiver sensitivity to block noise
pulses is itself introducing noise. As with everything else in life,
it's a trade-off.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 9/3/2017 9:40 AM, Jim Brown wrote:
On 9/3/2017 9:18 AM, K9MA wrote:
I have never found the K3 noise blanker to be effective.
<SNIP>
BTW, the K3 noise blanker uses a filter with a bandwidth of about 100
kHz.
<SNIP>
The K3 NB is really TWO blankers, operating in two different IFs. Each
can be tweaked for various kinds of noise from the menu system.
Access the menu by a Long Push of the NB button.
It's important to understand that there are many kinds of noise. Noise
blankers are most effective on IMPULSE NOISE, which is the result of
something arcing, usually in the power system, but also electric
fences and neon signs.
Most of the residential noise we hear today is ELECTRONIC noise,
generated by switch-mode power supplies and microprocessors. Noise
blankers must be very different to suppress this sort of noise. The
menu tweaks provided by the K3, K3S, KX3, and KX2 are very critical to
making the NB effective on the noise you're experiencing. One size
does NOT fit all.
73, Jim K9YC
______________________________________________________________
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
Message delivered to arch...@mail-archive.com
