Question about the Timewave ANC-4
 

John Plimmer wrote:
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.

Maybe it is a QC issue with MFJ? They seem to be notorious for somewhat
unreliable and variable QC.

John Barnard

Question about the Timewave ANC-4
 

John Barnard wrote:
John Plimmer wrote:
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.

Maybe it is a QC issue with MFJ? They seem to be notorious for somewhat
unreliable and variable QC.

John Barnard

Could be - my own MFJ-1026 chops out the offending stations really
well. If I were a MW aficionado, I'd take it everywhere.

Bruce Jensen

Question about the Timewave ANC-4
 

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.

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.

I've been experimenting some more with the ANC-4 / H-800 combination. I
now have the H-800 situated in a nice spot outdoors, and have noticed
something odd when it comes to eliminating noise. As soon as I turn on
the ANC-4, using the H-800 as the noise antenna, the noise is often
already minimized. For example, the noise level might immediately drop
from S6 to S3, and adjusting the noise gain and noise phase controls
will have little effect (good or bad) on this S3 noise level. This
doesn't happen everytime, but it happens a lot...most of the time.

If I then use a wire as my noise antenna, the noise level might drop
one or two S units as soon as I turn the ANC-4 on, but it takes some
knob twiddling to get the noise level down to the S3 reading that I get
automatically and immediately when using the H-800. And the best result
using the wire is always the *same* as the result I get straight away
using the H-800. Always.

I've puzzled over why this is. I think it must have something to do
with the fact that the H-800 has quite a bit more gain than the wire,
making it a better 'match' for the main antenna...which means a lot of
the work is done for me? This is just a guess.

Question about the Timewave ANC-4
 

Start by getting the reception equal in the two antennas.

The gain on the noise antenna should be set so that the main antenna
with the noise antenna disconnected (or unpowered, if active) is the
same S meter reading as the noise antenna with the main antenna
disconnected (or unpowered, if active).

You have to shade that to compensate for the phase control increasing
the gain at either extreme setting, but at least you start in the
right ballpark.

That the loop is itself directional introduces a complication. What
you want equal is the signal you're trying to eliminate, in both
antennas.

It can happen that the signal is already nulled in the loop, in which
case the loop can't help in nulling the signal in the other antenna.
Either reorient the loop or listen with the loop alone, in this case.
--
Ron Hardin


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

Question about the Timewave ANC-4
 

Bob Dobbs EC42 wrote:
On Wed, 06 Sep 2006 17:45:13 -0700, Steve wrote:

've been experimenting some more with the ANC-4 / H-800 combination. I
now have the H-800 situated in a nice spot outdoors, and have noticed
something odd when it comes to eliminating noise. As soon as I turn on
the ANC-4, using the H-800 as the noise antenna, the noise is often
already minimized. For example, the noise level might immediately drop
from S6 to S3, and adjusting the noise gain and noise phase controls
will have little effect (good or bad) on this S3 noise level. This
doesn't happen everytime, but it happens a lot...most of the time.

If I then use a wire as my noise antenna, the noise level might drop one
or two S units as soon as I turn the ANC-4 on, but it takes some knob
twiddling to get the noise level down to the S3 reading that I get
automatically and immediately when using the H-800. And the best result
using the wire is always the *same* as the result I get straight away
using the H-800. Always.

I've puzzled over why this is. I think it must have something to do with
the fact that the H-800 has quite a bit more gain than the wire, making
it a better 'match' for the main antenna...which means a lot of the work
is done for me? This is just a guess.

You'll have to evaluate which provides the better NR;
the reduction from the loops null,
or the null from the inverse phasing.
If the loop is alredady nulling the noise source then it might not be
providing adequate noise signal to the ANC-4 for its inversion process,
in which case you might try peaking the loops noise signal.


--

Echo Charlie 42
San Diego, California

I don't think the problem is due to the orientation of the loop because
we're talking about something that happens all the time and not just in
relation to one or two particular signals. I'm just about convinced
that the H-800 is simply providing more signal than the ANC-4 can
handle. I haven't tried any form of attenuation yet, but am thinking
about how to arrange that.

Steve

Question about the Timewave ANC-4
 

In article . com,
"Steve" wrote:

Bob Dobbs EC42 wrote:
On Wed, 06 Sep 2006 17:45:13 -0700, Steve wrote:

've been experimenting some more with the ANC-4 / H-800 combination. I
now have the H-800 situated in a nice spot outdoors, and have noticed
something odd when it comes to eliminating noise. As soon as I turn on
the ANC-4, using the H-800 as the noise antenna, the noise is often
already minimized. For example, the noise level might immediately drop
from S6 to S3, and adjusting the noise gain and noise phase controls
will have little effect (good or bad) on this S3 noise level. This
doesn't happen everytime, but it happens a lot...most of the time.

If I then use a wire as my noise antenna, the noise level might drop one
or two S units as soon as I turn the ANC-4 on, but it takes some knob
twiddling to get the noise level down to the S3 reading that I get
automatically and immediately when using the H-800. And the best result
using the wire is always the *same* as the result I get straight away
using the H-800. Always.

I've puzzled over why this is. I think it must have something to do with
the fact that the H-800 has quite a bit more gain than the wire, making
it a better 'match' for the main antenna...which means a lot of the work
is done for me? This is just a guess.

You'll have to evaluate which provides the better NR;
the reduction from the loops null,
or the null from the inverse phasing.
If the loop is alredady nulling the noise source then it might not be
providing adequate noise signal to the ANC-4 for its inversion process,
in which case you might try peaking the loops noise signal.


--

Echo Charlie 42
San Diego, California

I don't think the problem is due to the orientation of the loop because
we're talking about something that happens all the time and not just in
relation to one or two particular signals. I'm just about convinced
that the H-800 is simply providing more signal than the ANC-4 can
handle. I haven't tried any form of attenuation yet, but am thinking
about how to arrange that.

You can build an attenuator of any value with three resistors in a metal
box with two appropriate connectors.

--
Telamon
Ventura, California

Question about the Timewave ANC-4
 

Just swap the noise and main antennas

--
Ron Hardin


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

Question about the Timewave ANC-4
 

Ron Hardin wrote:
Just swap the noise and main antennas

Hey, Ron, does the ANC model provide a switch to accomplish this? The
MFJ does not, and that's my main gripe about that unit (I am going to
install a switch one of these days...)

Thanks,
Bruce
******

Question about the Timewave ANC-4
 

bpnjensen wrote:

Ron Hardin wrote:
Just swap the noise and main antennas

Hey, Ron, does the ANC model provide a switch to accomplish this? The
MFJ does not, and that's my main gripe about that unit (I am going to
install a switch one of these days...)

Thanks,
Bruce
******No, and worse, the connectors differ. That's why you need a box
full of adapters around the house.

--
Ron Hardin


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

Question about the Timewave ANC-4
 

Bob Dobbs EC42 wrote:
On Wed, 06 Sep 2006 20:13:21 +0000, John Barnard wrote:

Maybe it is a QC issue with MFJ? They seem to be notorious for somewhat
unreliable and variable QC.

That QC notoriety is so predictably reinforced that I choose to never
repeat my experiences with it. This includes the products of the newly
acquired Ameritron division too.



I currently have 5 different MFJ products and cannot claim any fault
on any of those items; they all do what they are supposed and do it
well. I did have an MFJ analogue audio processor which I sold when I
picked up a MFJ DSP unit. My overall experience has been positive but I
have certainly read enough to realize that there are problems with MFJ.

Thanks for the heads up on the Ameritron acquisition; I didn't notice
that MFJ acquired that company.

JB