"0ff_Ramp" wrote in message ...
"mystery" static in my area.... S-9 worth of noise!

What do you (not) know about this noise?

This is a superb question, because the ability of the device to remove
noise has alot to do with the nature of the noise. If the noise is
local and well-defined, if it is coming into your system via the
antenna (as opposed to the electrical lines) and especially if it is
the *only* bad noise you have, then a noise canceller will probably
take it out quite nicely. If the noise is distant (such as an
offending HF station via skywave) and the other two criteria still
apply, it will still work, but not quite as well.

If any two of these criteria are not met, then it is unlikely that the
unit will give satisfaction. For two different noise sources, two
units in series might work, but I have never tried this. For this, it
is probably preferable to have a radio that has noise-cancelling
devices (Noise blanker, DSP, etc) plus a single external unit.

Also, some units (the MFJ-1026 notably, which I use) comes with a
built-in aux "noise" antenna. It works, a bit (especially on certain
wavelengths such as 25m and 60m - 90m, where it works quite well) -
but for serious noise, it is best to have a dedicated external antenna
that comes reasonably close in character to your main antenna. This,
because you want both antennas to be "hearing" the same noise. Two
roughly parallel 40-foot (12m) or longer random wires about 20-50 feet
(6m to 16m) apart would be nearly ideal; but I use a DX-Ultra
(essentially a center-fed dipole assembly) with a random wire of about
60 feet as the aux antenna, and it works pretty well for most noise.

The way the units are configured, you can phase one, the other or both
antennas together for the best noise reduction. On the MFJ units, the
aux antenna has both a gain control and a preamp, which is nice, but
it would be even better if these features were switchable from aux to
main sometimes (a fairly simple modification inside the unit can
achieve this, if you aren't afraid to do minor surgery).

With my unit in stock condition and with the internal jumpers
configured per the instructions, I can reduce most constant modest
static 3 to 5 S-units; strong static or impulse noise from S-9 down to
below the noise floor at S-1 or less (a good noise blanker will
accomplish about as much); offending groundwave stations (on SW or MW)
a comparable amount; and offending skywave stations about 3 S-Units
(typically). These correspond to dB reductions of about 18 up to 50
dB or more, depending on the noise.

When I have an obnoxious noise that cannot be remedied by the noise
blanker, notch or DSP, I tune off the desired station frequency to a
quiet spot nearby 5 or 10 kHz away), adjust the noise levels and phase
according to the directions until the noise is reduced maximally, then
tune back to the station. You don't want to tune very far away to
adjust the device, because the settings are frequency-dependent. Done
properly, this works very well.

The unit advertises that it can take out static crashes from lightning
and other intermittent noise sources, and it may be true, but the
nature of these noises makes it very difficult to adjust the device
with any precision.

I like mine alot - for the city/suburb dweller or the random person
with horrid noise, it works minor miracles.

Bruce Jensen