ANC-4 principle?
 

How does an ANC-4 work, _as to the phase shift_? Is the one input just split
and one leg run thru a capacitor and resistor to ground, and you select
some linear combination of the two inputs?

That selection then being added to the reference antenna's.

I'm interested in building an 8-input ANC-4, in effect.
--
Ron Hardin


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

On Mon, 18 Apr 2005 13:22:17 GMT, Ron Hardin
wrote:

How does an ANC-4 work, _as to the phase shift_? Is the one input just split
and one leg run thru a capacitor and resistor to ground, and you select
some linear combination of the two inputs?


The ANC-4 noise canceller works by cancelling the noise before it
affects the receiver AGC circuits. It connects between you antenna and
receiver. A second antenna acts as a noise pickup. The front panel
controls allow adjustment of signal phase and magnitude from the two
antennas to effect noise cancellation. The ANC-4 can also operate as
an active antenna using a noise antenna and noise gain control to
amplify antenna output. And, it can be used as a diversity combiner to
pick up weak signals or null interfering signals. Complete
specifications on the ANC-4 are available from Timewave's web site.

Danny, K6MHE

Dan Richardson wrote:

On Mon, 18 Apr 2005 13:22:17 GMT, Ron Hardin
wrote:

How does an ANC-4 work, _as to the phase shift_? Is the one input just split
and one leg run thru a capacitor and resistor to ground, and you select
some linear combination of the two inputs?


The ANC-4 noise canceller works by cancelling the noise before it
affects the receiver AGC circuits. It connects between you antenna and
receiver. A second antenna acts as a noise pickup. The front panel
controls allow adjustment of signal phase and magnitude from the two
antennas to effect noise cancellation. The ANC-4 can also operate as
an active antenna using a noise antenna and noise gain control to
amplify antenna output. And, it can be used as a diversity combiner to
pick up weak signals or null interfering signals. Complete
specifications on the ANC-4 are available from Timewave's web site.

Danny, K6MHE

The question I had was how it achieves a phase shift, though.
--
Ron Hardin


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

More than a year ago I downloaded a copy of the circuit diagram
from the Timewave website. My interpretation of the diagram is
that the noise antenna goes to Q1 that has a transformer-coupled
output whose phase, relative to the input, can be shifted by varying
R6. From there the phase-shifted 'noise' is applied to Q2 and a
portion of the output, determined by R12, passes to Q3, probably
a buffer stage. In T4 the phase-shifted 'noise' is combined with the
main antenna signal to give the desired output. I hope this explanation
is generally correct and is of some use.


"Ron Hardin" wrote in message
...
How does an ANC-4 work, _as to the phase shift_? Is the one input just
split
and one leg run thru a capacitor and resistor to ground, and you select
some linear combination of the two inputs?

That selection then being added to the reference antenna's.

I'm interested in building an 8-input ANC-4, in effect.
--
Ron Hardin


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

"Ron Hardin" wrote in message
...


I'm interested in building an 8-input ANC-4, in effect.

This may or may not be of interest but here it is anyway. Doug Demaw did
construction articles in the May 96 and July 97(improved version) issues of
CQ for a "QRN Squelcher". He did a similar article in Monitoring Times but
omitted the TR switch He compares this unit as an equal to the ANC4.
I ordered the circuit boards for the project from Far circuits
(www.farcuits.net) but haven't started the project yet, saving it until I
finish some other already started projects. RM~

PS, Far has the boards listed in the Audio section of their online catalog
and they will supply a copy of the CQ article for an extra $1.50.

Ron Hardin wrote in message
...
How does an ANC-4 work, _as to the phase shift_? Is the one input just
split
and one leg run thru a capacitor and resistor to ground, and you select
some linear combination of the two inputs?

That selection then being added to the reference antenna's.

I'm interested in building an 8-input ANC-4, in effect.

It works the same way as the one on the Hallicrafters (or was it Hammerlund)
receiver back in the 1940/50's. Odd that the rice boxes don't come with one
already built-in---they are not complicated circuits.

Vic Misek has a couple of circuits in his Beverage Antenna Handbook. He
uses them to null steer parallel wires or two-wire Beverage antennas

RG