K3 Noise blanker

[Gary Smith]

Another question for K3 owners:

I have a severe case of RFI which is intermittent and I wrote about
it in a post to the RFI forum. You can hear an example of it here if
you wish, it's less than a meg in size:http://doctorgary.net/QRM-
1.mp3 Not to go into much detail on the specific RFI here but to
understand the character of the issue, read my detailed post on the
rfi reflector and go here:
http://lists.contesting.com/pipermail/rfi/2008-October/006238.html

I have a Corsair II whose noise blanked usually does a fair job of
eliminating this RFI. My Omni V does nothing to reduce this RFI. It
usually happens at night. As I am more into low band DXing, this is
an issue.

My question for this forum is to ask how satisfied you are with the
noise reduction in the K3 as opposed to your experiences with other
recievers with similar RFI as I am experiencing.

I have not to date found the source of the RFI so perhaps a better
noise blanker is what I will find that is my best option. The K3
seems to be getting a lot of great press so I am interested in the
K3. A superior noise blanker is imperitave but I would not be willing
to have a radio that hears less well than the Corsair II or Omni V.

I have a few other K3 questions but will ask them in separate posts.

Thank you,

Gary
KA1J
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[John-483]

At 09:20 AM 10/10/08, you wrote:

>I have a severe case of RFI which is intermittent

Gary,

It sounds like you need the power company more than an NB. I had
noise just like that, intermittent.  I turned out to be a transformer
on a power pole. It could be arcing due to a faulty power line
connection.  You need to have the power company open the line at a
fuse point, removing power from the line. You will need to run your
radio off batteries while they are checking. I found that most power
companies will work with their customers to resolve a problem.

Good luck!
John
k7up  

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[David Woolley (E.L)]

Gary Smith wrote:

> I have a Corsair II whose noise blanked usually does a fair job of

> My question for this forum is to ask how satisfied you are with the
> noise reduction in the K3 as opposed to your experiences with other

You are confusing two different concepts.  I believe the K3 supports both.

In its terminology, noise blanking is used to elimenate broadband spikes
and basically uses a very broadband detector, early in the receiver, to
mute the signal later in the receiver, where it has suffered enough
group delay to allow the blanker to react.  It needs to be done in the
analogue processing, at least when digitising at less than 10s of Ms/s

Noise reduction is intended for relatively narrow band, or continuous
sources.  I believe it includes an automatic notch filter, but it may
also involve blanking audio sub-bands with little energy, etc.  It's
done in the software defined part of the system.


--
David Woolley
"The Elecraft list is a forum for the discussion of topics related to
Elecraft products and more general topics related ham radio"
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