Bob Dobbs EC42 wrote:
A technique called successive overrelaxation is the most successful in
searching for a null.

Are you suggesting some 'play' in the null seek process?

No, it's simple geometry.

Draw a long narrow ridge running SW to NE on a piece of paper. A line will do.

Now imagine that the middle of your line segment is the actual null sought.

Suppose gain moves you N-S, and phase moves you E-W.

Start S of the SW end of your line. Move N to the best null, then E to the best
null, then N to the best null, the E to the best null, etc.

You observe you follow a zigzag path making no progress up the ridge to the true
null to speak of.

Now do the same thing going _past_ the best null. Your progress is swift towards
the true null.

Successive overrelaxation goes a fixed fraction past the best null each time.

It is unnecessary where the ridge is instead a nice circle, for two steps take you
to the true null. But a long narrow ridge is very common, and SOR is the way to
find the null then.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

There is no such thing as time.time does not exist.
cuhulin

Steve wrote:
I have a question about how the ANC-4 works. Specifically, it's about
the antennas that you connect to the ANC-4 in order to cancel noise or
make a 'phased array'.

In some contexts, when noise is a problem, people will say that you
want to keep the "noise antenna" that you use with the ANC-4 as small
as possible. This is because you want the noise antenna to hear *only*
the noise, which will be phased out, and not the target signal, which
you don't want to be phased out. The suggestion here is clearly that,
if your noise antenna *does* hear the target signal, you're going lose
signal along with noise.

However, when people use the ANC-4 to establish phased arrays of two or
more antennas, this is usually with a couple of serious antennas,
widely separated, *both* of which can hear the target signal. Hence my
question: When the ANC-4 is connected to two largish antennas, both of
which are capable of hearing the target signal, what prevents the
desired signal from simply being phased out? Is determining what gets
phased out just a matter of carefully adjusting the controls on the
ANC-4?

Thanks!

Steve

By this time I've used the ANC-4 enough to know that it's a big help.
Where noise is concerned, it makes much more of a difference for me
than running off batteries, ferrite cores, etc. I'm kicking myself for
not getting one of these sooner. I find that my noise floor usually
drops one or two S-units the instant I turn the ANC-4 on. Adjusting the
controls then can make a huge difference; and at my location it almost
always makes more of a difference than is necessary to compensate for
the 6 dB insertion loss. It especially shines during the day on LSB and
USB.

I've tried it with a lot of different antennas, but I'll be
experimenting with antennas for quite some time, I suspect. I did
eventually get good results using the H-800 active whip. However, where
noise reduction is concerned, I find that I get the best results using
a wire antenna that snakes its way between my house and the neighbor's
house and then back near some power lines. The nulls with the wire
antenna are just as deep as they are with the H-800, but they're a lot
easier to find. These conclusions are pretty tentative, though, as I am
still experimenting and trying out different arrangements.

On the whole, I think the ANC-4 is great and worth every penny if you
have problems with noise. It works as advertised.

Steve

Steve = tks 4 that, a very informative and interesting post.

I want to ask the group this:
I had a MFJ-1026 noise canceller when I lived in suburban Joburg.
I tried every sort of antenna combination - verticals, horizontals, whips
and Windom's, but the thing never abated the noise to any appreciable
extent, so I gave up on it after a year of fiddling and experimenting.

Now I have passed it on to a friend who lives in a very noisy suburb of Cape
Town. He did no better than me with it and also gave up on it. Now he has a
Wellbrook ALA1530 which gives him decent results.

So my question is this:
Is the Timewave ANC-4 markedly superior to the MFJ1026?

--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Braun T1000, Sangean 818 & 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

"Steve" wrote in message
oups.com...
By this time I've used the ANC-4 enough to know that it's a big help.
Where noise is concerned, it makes much more of a difference for me
than running off batteries, ferrite cores, etc. I'm kicking myself for
not getting one of these sooner. I find that my noise floor usually
drops one or two S-units the instant I turn the ANC-4 on. Adjusting the
controls then can make a huge difference; and at my location it almost
always makes more of a difference than is necessary to compensate for
the 6 dB insertion loss. It especially shines during the day on LSB and
USB.

I've tried it with a lot of different antennas, but I'll be
experimenting with antennas for quite some time, I suspect. I did
eventually get good results using the H-800 active whip. However, where
noise reduction is concerned, I find that I get the best results using
a wire antenna that snakes its way between my house and the neighbor's
house and then back near some power lines. The nulls with the wire
antenna are just as deep as they are with the H-800, but they're a lot
easier to find. These conclusions are pretty tentative, though, as I am
still experimenting and trying out different arrangements.

On the whole, I think the ANC-4 is great and worth every penny if you
have problems with noise. It works as advertised.

Steve

Steve wrote:
Steve wrote:
I have a question about how the ANC-4 works. Specifically, it's about
the antennas that you connect to the ANC-4 in order to cancel noise or
make a 'phased array'.

In some contexts, when noise is a problem, people will say that you
want to keep the "noise antenna" that you use with the ANC-4 as small
as possible. This is because you want the noise antenna to hear *only*
the noise, which will be phased out, and not the target signal, which
you don't want to be phased out. The suggestion here is clearly that,
if your noise antenna *does* hear the target signal, you're going lose
signal along with noise.

However, when people use the ANC-4 to establish phased arrays of two or
more antennas, this is usually with a couple of serious antennas,
widely separated, *both* of which can hear the target signal. Hence my
question: When the ANC-4 is connected to two largish antennas, both of
which are capable of hearing the target signal, what prevents the
desired signal from simply being phased out? Is determining what gets
phased out just a matter of carefully adjusting the controls on the
ANC-4?

Thanks!

Steve

By this time I've used the ANC-4 enough to know that it's a big help.
Where noise is concerned, it makes much more of a difference for me
than running off batteries, ferrite cores, etc. I'm kicking myself for
not getting one of these sooner. I find that my noise floor usually
drops one or two S-units the instant I turn the ANC-4 on. Adjusting the
controls then can make a huge difference; and at my location it almost
always makes more of a difference than is necessary to compensate for
the 6 dB insertion loss. It especially shines during the day on LSB and
USB.

I've tried it with a lot of different antennas, but I'll be
experimenting with antennas for quite some time, I suspect. I did
eventually get good results using the H-800 active whip. However, where
noise reduction is concerned, I find that I get the best results using
a wire antenna that snakes its way between my house and the neighbor's
house and then back near some power lines. The nulls with the wire
antenna are just as deep as they are with the H-800, but they're a lot
easier to find. These conclusions are pretty tentative, though, as I am
still experimenting and trying out different arrangements.

On the whole, I think the ANC-4 is great and worth every penny if you
have problems with noise. It works as advertised.

Steve

I have the ANC-4 (original JPS version), which was a great help with
random wire antennas. It seems to be of no use with my welbrook. I
tried to use the built-in noise antenna on the ANC-4 to make a null
with my Wellbrook and never managed to get that to work. Of course,
the Wellbrook is a very quiet antenna in the first place.

wrote:
I have the ANC-4 (original JPS version), which was a great help with
random wire antennas. It seems to be of no use with my welbrook. I
tried to use the built-in noise antenna on the ANC-4 to make a null
with my Wellbrook and never managed to get that to work. Of course,
the Wellbrook is a very quiet antenna in the first place.

It works fine with mine, using a wellbrook ala1530 and an active whip
(or another wellbrook 1530).

I don't think the built-in noise antenna is likely to work though.
I tossed mine out.

With a wellbrook loop and a whip _located right near it_ (near means
fraction of a wavelength), you get the same pattern as with two
whips separated by a quarter wavelength, but without using any
real estate, laid out in the plane of the loop, ie. a double null
at one endfire and a max at the other endfire, opening up to a V
and sweeping to a double null at the opposite endfire and max at the
other.

Two loops separated by a quarter wavelength are handy for some things,
like nulling in advance a particular station, and then nulling another
altogether with the ANC-4, without having to go to multiple ANC-4's.

There is an odd thing with two loops, though.

For nulling a station by phasing, paradoxically, you should put the
station near the max of the loop, not the null. The phase of the
signal from the loop gets more and more unstable as you approach the
loop's null, and harder and harder to phase out with the ANC-4, is
the reason. It's comparatively easy near the loop's max.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

Ron Hardin wrote:
wrote:
I have the ANC-4 (original JPS version), which was a great help with
random wire antennas. It seems to be of no use with my welbrook. I
tried to use the built-in noise antenna on the ANC-4 to make a null
with my Wellbrook and never managed to get that to work. Of course,
the Wellbrook is a very quiet antenna in the first place.

It works fine with mine, using a wellbrook ala1530 and an active whip
(or another wellbrook 1530).

I don't think the built-in noise antenna is likely to work though.
I tossed mine out.

OK. I'll try an active whip. Still, I think the built in noise antenna
should work. It was fine when I was cancelling local computer noise.

With a wellbrook loop and a whip _located right near it_ (near means
fraction of a wavelength), you get the same pattern as with two
whips separated by a quarter wavelength, but without using any
real estate, laid out in the plane of the loop, ie. a double null
at one endfire and a max at the other endfire, opening up to a V
and sweeping to a double null at the opposite endfire and max at the
other.

Two loops separated by a quarter wavelength are handy for some things,
like nulling in advance a particular station, and then nulling another
altogether with the ANC-4, without having to go to multiple ANC-4's.

There is an odd thing with two loops, though.

For nulling a station by phasing, paradoxically, you should put the
station near the max of the loop, not the null. The phase of the
signal from the loop gets more and more unstable as you approach the
loop's null, and harder and harder to phase out with the ANC-4, is
the reason. It's comparatively easy near the loop's max.

--
Ron Hardin


On the internet, nobody knows you're a jerk.

John Plimmer wrote:
Steve = tks 4 that, a very informative and interesting post.

I want to ask the group this:
I had a MFJ-1026 noise canceller when I lived in suburban Joburg.
I tried every sort of antenna combination - verticals, horizontals, whips
and Windom's, but the thing never abated the noise to any appreciable
extent, so I gave up on it after a year of fiddling and experimenting.

Now I have passed it on to a friend who lives in a very noisy suburb of Cape
Town. He did no better than me with it and also gave up on it. Now he has a
Wellbrook ALA1530 which gives him decent results.

So my question is this:
Is the Timewave ANC-4 markedly superior to the MFJ1026?

John,

Was your 1026 modified for use below 2 MHz? Mine was modified several
years ago and it worked much better in the mediumwaves after the
modification.

JB

Bob Dobbs EC42 wrote:
On Sun, 03 Sep 2006 19:37:31 +0200, John Plimmer wrote:

So my question is this:
Is the Timewave ANC-4 markedly superior to the MFJ1026?

I have a local HAM friend that swears by his MFJ-1026, even though he's
never had the ANC-4, OTOH I swear by my ANC-4 never having has the 1026.
I've not even seen the MFJ-1026 unit to see if my prejudice against MFJ is
justified or not.


I've owned an ANC-4 and still own a modified 1026. I've found the 1026
to be better at killing noise and nulling out stations. That being said,
I've found the Quantum Phaser to be better than the 1026.

JB

Yes, it was MW modified and we even took it on DXpeditions and tried it for
phasing and nulls with the beverage antenna's, but results were not worth
all the knob twiddling, that's why we gave up on it.

don't get me wrong - it did work, that is it was not non-functional, just we
did not get the good results that others report.
--
John Plimmer, Montagu, Western Cape Province, South Africa

So my question is this:
Is the Timewave ANC-4 markedly superior to the MFJ1026?

John,

John Barnard wrote:
Was your 1026 modified for use below 2 MHz? Mine was modified several
years ago and it worked much better in the mediumwaves after the
modification.

JB