[Elecraft] K4HD question

Fred Jensen k6dgw at foothill.net
Wed May 29 21:57:39 EDT 2019


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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