Stephen,
Turn the preamp on and scratch/tap the Q21 case with a metallic object
(screwdriver) while turning the NB on and off. If the NB is working,
you will hear the sharp impulse clicks substantially reduced.
Many types of power line noise are not handled by the KNB2, it is great
on impulse noise, such as that from an automobile engine (not diesel).
The KDSP2 does a good job on many other types of noise.
73,
Don W3FPR
Stephen Prior wrote:
I built the noise blanker kit for my K2 s/no. 4905 (I think) a few weeks
back, and I am beginning to wonder if it is working. I can not tell any
difference between NB1, NB2, whether hi or lo threshold.
It is said that it works against the sort of pulse noise I get here from
power lines occasionally, yet it makes no difference. Since all the cars in
the family are diesel powered and I am some distance from a quiet country
road, I have not had the opportunity to see whether it works on petrol
engined ignition noise. My experience with noise blankers in other radios
is that you can usually hear some change when it is switched in, but I
don't.
Am I expecting too much? Or could there possibly be a fault which would
still pass the rx signal through the noise blanker board and yet stop the
noise blanker working? Had I not read how good it is supposed to be, and
had I not made it myself, I probably would not be asking the question!
_______________________________________________
Elecraft mailing list
Post to: [email protected]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
