Noise blankers were designed for repetitive impulse noise, the largest
former example of which was ignition noise from vehicles. They have not
ever been very effective against power line hash which tends to be
non-impulsive and highly random. These days, repetitive ignition noise
is not a problem for many, don't know why, there are still spark plugs
in there. Power line hash comes from a myriad of sources ... hardware
anchoring insulators, transformers, fuses, and the like, as well as
micro arcing across dust covered insulators. It's highly random, over
even small time intervals, and just not the enemy noise blankers were
designed to fight. If Wayne had graduated from Hogwarts, he might have
some magic to make them work on power line hash. Lacking that, not sure.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 5/29/2019 6:43 PM, K9MA wrote:
I've never found the K3 noise blanker to be very effective on power
line noise, and I've tried all possible combinations of settings. If
the K4 noise blanker were really effective on line noise, I might buy
one.
73,
Scott K9MA
On 5/29/2019 20:39, Wayne Burdick wrote:
There are some subtleties in noise blanking that may distinguish the
two modes (direct sampling or superhet). The blanking used in
direct-sampling should have an advantage on complex, high-duty-cycle
noise sources, while the hardware blanking modules used in the
superhet may have an advantage with extremely short pulse sources.
We'll be extensively testing and comparing them.
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