[Elecraft] KNB2 does not work on my power line noise

[Dale Boresz]

Hello Roger,

I've had many battles with powerline noise, and have made a few 
observations:
- Rarely can I tell just by listening to it, whether or not the NB will 
take care of it or not. Sometimes it does and sometimes it doesn't. 
Comparing the effectiveness of the NB with that of my IC-746PRO yields 
pretty similar results.

- If you find that the NB is not effective, try switching in the preamp 
- even though you don't need it otherwise. I've found (and other have 
reported this as well), that sometimes the noise level is too low for 
the NB to effectively operate upon it, and turning on the preamp will 
suddenly allow the NB to do it's job. It has worked for me many times.

- Some types of powerline noise cannot be removed with any type of 
blanker because the rise and/or fall times are simply too long. The NB 
works best on impulse noise with fast rise/fall times.

- I've been using the MFJ-1025 and MFJ-1026 for years, and although it 
can be a little cumbersome at times to adjust, it will often make the 
difference between being able to operate, and not. I've successfully 
reduced noise levels as high as S9, down to nothing. Over the years, 
I've learned that a good 'noise sense' antenna is a must. Also, spend 
the extra few $$ for the MFJ-1026 which has an additional preamp on the 
noise antenna input; this will help a lot when the noise sense antenna 
isn't quite as good as it should be. For a noise sense antenna, I've 
actually strung a doublet parallel to and beneath the power line so that 
it picks up the noise well, and this arrangement works quite well. 
Expect to do a lot of experimenting with placement of the noise antenna, 
but it's well worth the time spent.

- The power line company (at least our local one) is usually fairly 
responsive, especially if you can give them an idea of where the trouble 
may be located. I found the source of my line noise problem by riding a 
bicycle around the neighborhood with an HT, and was able to localize it 
to a specific utility pole. When I told the folks at the power company 
that I had located the exact pole, and provided them with the pole 
number, they repaired it within a couple of days.

73,
-Dale / wa8sra

Roger Marrotte wrote:

>...It sounded just like mine.  He turned on his noise blanker and the noise was
>gone.  I then connected my K2 to his antenna turned on my noise blanker and
>the noise was gone!  I guess my noise is different enough for the noise
>blanker not to work on it.  Does anyone have any suggestions for me.
>
>Roger, W1EM
>  
>