How to Connect and Use the ANC 4 with the FT1000MP (Now with comments
on the MFJ 1026)
For all who asked here is the set up for the ANC-4 so that there is no
delay in the switching (originally from a note by N6TV on the Yaesu
Reflector from Mach 1997): On the 1000MP: Ant A to the main station
antenna Rx Antenna "IN" to the "Radio" port of the ANC-4. Rx Antenna
"OUT" to the "Main Ant" port of the ANC-4
On the ANC-4: "Noise Ant" to the whip or wire noise antenna."12V" to
supply (or dc out on MP)
To use the ANC-4 press the "RX Ant" switch on the 1000MP. The MP can now
be used at QSK speed with no switching delay, and no RF goes through the
ANC-4 (its relay will NOT activate). 73 Steve N2QLQ
I've found the best method (and easiest) method to connect the ANC-4
with the MP is to use it with the rx antenna out (generally used for
external RX) jack feeding the antenna input of the ANC-4, and the radio
output of the ANC-4 connected to the external RX antenna in jack on the
MP. This way, the ANC-4 always sees the signal from your main A or B
antennas, and to toggle the MP receiver to the ANC-4, just punch the
ANT/RX button on the front panel. Noise antenna connects to the ANC as
usual. This eliminates the issue with switching RF, as the ANC-4 never
needs to go into "transmit" mode. Works great here, with my intermittent
line noise. I can reduce the crud from S9+20 to S4-5 or band noise level
in most cases. I use a low G5RV for the noise antenna, as providing
enough noise signal to match what is picked up by the primary antenna is
problematic on some bands. Some noises, particularly when multiple
sources are involved, can only be nulled 20db or so with the ANC-4. The
MP noise blankers provide an adequate supplement in these cases. 73! -
Mark
Input from Steve N2QLQ: I can add a few things about these noise
cancellers, since I spent some quality time with them. First, the
MFJ1025/1026 is a derivative of a unit I've used here for some time.
Unlike other similar units, the MFJ does NOT go through wild amplitude
changes as phase is varied. It has a nearly level amplitude as phase is
rotated, generally much less than 1 dB amplitude ripple. That is very
important, because the last thing you want to do is have to go back and
forth between gain controls and phase every time the phase changes. One
design, despite claims, does not even rotate phase! Nulling noise is a
matter of luck! The phase controls changes only the level, and flips
phase 180 degrees. The primary drawback of the MFJ (and other units) is
IMD performance and noise floor. My unit uses $50 FET's (for low noise
high IMD performance but would cost nearly $1000 to market. If IMD from
out-of-band signals is a problem, the MFJ unit can be greatly improved
by adding a parallel L/C circuit across each "gain" pot, from high end
of each pot to ground. The component values are 2 uH in parallel with
3.35 NF (3350 uuF). (I use these components and others across each
Beverage matching system on the low Z side to keep strong SW BC signals
from bothering my amplifiers. I've measured signal levels of three VOLTS
from some Beverages pointed at SW BC stations thousands of miles away!)
This kills gain above 3 MHz and below 1.6 MHz, but this makes the unit
much better for top band use on big antennas. None of these units work
well for most storm QRN, unless the storm is a narrow area of
thunderstorms in one general direction. They will however, be useful for
peaking a signal by adding the desired signals from two different
antennas. That's almost always good for two or three dB extra. S/N. W8JI
Tom
I have been reading the notes with regards to the ANC-4 noise cancelling
unit. First let me say that I have NO (ZERO) connection with JPS. I did
this as an academic experiment. I purchased an ANC-4 a couple of years
ago with the intention of using it for a non amateur purpose. I was
doing some experiments with VLF ("natural") radio reception, and found
that any power lines within a couple of miles swamped my receiver. I
came up with was, for me at least, a brilliant idea; a phase inverter.
Unfortunately none were commercially available specifically for 60 HZ
(and its multiples) and the few simple active filters I tried to make
did not work. I tried the ANC-4, and alas, it did not work either. So,
not to waste my money, I hooked it up with my MP. And in my situation,
it generally does a good job. It eliminates the computer birdies, and
often does a great job with power line noise. This evening on 20 meters,
there was a lot of local line noise. I measured it as S7 to 8, and when
the ANC-4 was on line, I could knock it down to S2 to 3. I then decided
to plot the results graphically, so I used a spectrum analyzer program,
and created 4 files which show the results pretty well. I tuned in a CW
signal, and captured a spectral plot for AGC off and ANC-4 on and off;
and AGC "slow" with ANC-4 on and off. I used CW without any filters as I
thought a single tone would show up better in the plots while the use of
no filters would be closer to the set up for phone operation. (Yes,
putting in a 500hz filter, or switching on the DSP helped without the
ANC-4, but that is not the point
of the exercise). I think two things have to be taken into account. All
noise cancelling devices probably will not work in all situations, and I
think that noise antenna type and placement may be critical. I don't
think it will be the same from station to station, just like RFI
problems are often very specific. So, that is the story, at least for
me. The ANC-4 is a useful device in my opinion and experience. If more
than just 1 or 2 people are interested, I will post the plots.
Input from Ron W4LDE: I also about a year and half ago started having
noise problems on 160-80 and 40 meters in the evenings only, sun-set to
sun-rise. Have tried unsuccessfully to tracking it down, so I bought the
MFJ-1026 over the other popular noise cancelling device from
Timewave.The noise I have experienced is birdies every 17 KC on 160-80
and 40 with signal strength decreasing as we go up in frequency. I use
it with a FT1000MP connected between aux antenna and antenna out on the
FT, don t have to worry about blowing the MFJ that way, still always the
possibility of hurting the FT though.
Observations,
1. You will need an external antenna , I found the internal antenna to
worthless for my noise issue. I use a forty meter dipole to fight the
noise, my main antenna is a double extended center feed zepp at 65 feet
used for 160-80-40 and 30 meters. The zepp runs east to west, the dipole
runs N to S and that's one problem I have, I do not have the yard or
supports to keep the antennas apart as far as I want if I run it E to W
as the Zepp. The 40 meter dipole is up about 20 feet.
On 40 meters I can null out noise as load as S-9 down to, S-0, I cant
hear it! Only drawback is the need to lower the over-all gain of the
receiving antennas to accomplish the null, I lost about 1 1/2 S units
comparing direct to the Zepp verses using the MFJ. I could if need get
the same S-meter reading but then the noise would be still in there but
at a reduce level.
On 30
meters I do not need it.
ON 80 Meters I can reduce the noise by anywhere from 6 to 8 S-units, however,
again I have to use a lower setting and lose about 2-3 S Units, that's worth it
getting rid of the noise.
On 160 meters the reduction is not as great as I would like, a larger cancelling
antenna other than the 40 meter antenna would perform better for 80 and 160.
2. The MFJ creates some of its own noise (Birdies) that are significant, I have
noticed two on each band, as example on 80 meters I have one around 3580 and
3804 plus or minus a few and at a S meter reading of S-9, this only occurs when
you use the internal preamp on the auxiliary antenna input, on 80 and 160 I have
to use it since the 40 meter antenna does not have the pickup to help cancel out
the 160 or 80 meter noise. On 40 meters I do not need the pre-amp.
I think the real question you want is would I buy it again, answer is probably,
it works, does it works a good as the Timewave ANC-4, I cant answer that but I
would like to try one out and compare the results here at this QTH. Regardless
of which one you purchase it should help, will it totally eliminate the noise?
Possibly, if not with a significant reduction. The consensus seems to be that an
external antenna is needed for either unit. W4LDE
