Duane A Calvin wrote:
Hi Ron,
I've looked at the Timewave (used to be the JPS ANC-4), and a
better option, the MFJ unit (has a better combination of phase options.)
It's nice in that if the bulk of your noise is coming from a single
source, you can phase-cancel it. However, in my case, the noise is
coming from multiple consumer electronics devices that are surrounding
me. So, this kind of phase cancellation unit only takes care of a small
number of noise sources. Darn it. And we won't even discuss how
difficult they are to use with a QSK radio . . .
73, Duane
For me, the most useful part of the mfj noise canceling device was being
able to use separate receiving and transmitting antennas and being able
to continuously vary the gain on the rx side. Of course one cannot
operate qsk this way, but it does allow me to use my vert on tx and the
zepp on rx with good isolation, quite conveniently.
Using the mfj in the noise canceling mode, I find that the sense antenna
needs be able to hear the noise about as well as the main antenna to be
effective. My zepp usually doesn't hear the noise sources very well and
the vertical hears nothing but. On 30 and 40 after sundown, the vert is
the tx antenna of choice by 6 to 10 db, so the separate antennas config
works well.
Also, the mfj super dsp has continuously variable noise reduction (much
less objectionable on cw than the Jupiter's nr) and the ability to
narrow the audio passband with very steep skirts. All these things
above taken together make a very high grinding city livable if not lovable.
Jerome
VA7VV - Vancouver
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