[Elecraft] Noise Blankers

[David Olean]

Hello Tom,
    I am plagued by excessive amounts of power line noise on 50, 144 and 
222MHz. It has been going on for years to the point where the FCC  (both 
Riley Hollingsworth and Laura Smith) have sent letters to the local utility. 
I have used several receivers and none really took out the noise as 
effectively as the K3 has. I find that for my situation, the DSP blanker is 
quite good when things get bad.  In the past I have seen other noise 
blankers get swamped out by so many noise pulses that they have lost 
effectiveness. Simple noises of maybe one or two arcing points can be 
removed, but 7 or 8 is another story. As more noise comes on, the blankers 
fare more poorly.  (Yes, one power pole can have 7 or 8 points that are 
generating rfi)  With the K3, I have been able to negate most of the noise 
and still am able to operate through the noise by adjusting the DSP NR 
settings along with IF blanking. I find that the DSP NR works better for my 
situation. My antennas are high and in the clear. The worst noise problem 
has come from a 34.5 KV line that is seven miles from my antenna. It is 
typically peaking S7 and is composed of many arcing tie wires and leaking 
insulators. Only the K3 has removed this noise as a factor in receiving. My 
other radios with only IF blanking do absolutely nothing to the noise in 
that direction.
    The nice thing is that you can tailor the effect on the fly and 
immediately tell which setting works best.  I am pleased with the DSP as it 
does not overload with strong signals. While it makes the audio sound 
somewhat ugly at aggressive settings, the overall outcome is positive. I am 
more than happy with the noise performance of the K3. It is quite a tool.  I 
believe the Flex Radio is another stellar performer in this area, but I have 
not tried it at my QTH.

Dave K1WHS

----- Original Message ----- 
From: "Tom Bickley" <k4na at hotmail.com>
To: <elecraft at mailman.qth.net>
Sent: Thursday, January 07, 2010 1:38 AM
Subject: [Elecraft] Noise Blankers


>
> I'm overdue for a new radio (at least, that's what I am telling my
> XYL). In considering the purchase, unfortunately one of the major
> considerations I must take into account is
> the noise blanker function. I have recently moved to an area with A LOT
> of power line noise. I have high voltage lines around my immediate QTH.
> It is a constant S3 to S5 on all bands above 7 MHz and, sometimes on
> really
> cold mornings, a seperate, additional noise kicks in that takes it to
> S9 or more. I am trying to locate these noise sources but have been
> unable to so far. I must run the noise blanker on my old TS-850s at all 
> times to help me manage this problem. With the NB engaged (which
> is 'always') I have audio distortion created from nearby signals,
> especially stronger  signals within 30
> kc's of my receive frequency, no matter at what level I run either of the 
> noise
> blankers.
>
> I would like to hear from K3 owners who might have
> 'line noise problems' and know how the noise blanker in your K3 handles
> the problem.
>
> Mni Tnx / 73 >  K4NA
>
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