R: [TowerTalk] AM Filter options

[Maurizio Panicara]

This is a correct argument.
A second antenna and null steering device able to equalize the amplitude and
180°  shifting the phase of the interfering signal, has a very good chance
of success.
This is maximally true with antennas (main and sense) having a small spacing
in term of  wavelenght. (typ. on MW)
In this case, infact, it's still possible to phase shift  and null a certain
signal, while any other signal is rarely (almost never) in the situation to
be nulled or attenuated too.
This happen because the signal cancellation is a matter of an extremely
precise phase shifting (reversal) that positively acts (to null) on a narrow
direction and also on a very precise signal phase.
In other words, it's also possible to discriminate a signal between two from
the same direction when their phase is different and constant.

73,
Mauri I$JMY



----- Original Message -----
From: Dale Martin <kg5u@hal-pc.org>
To: TowerTalk Reflector (E-mail) <towertalk@contesting.com>
Sent: Monday, May 01, 2000 10:58 PM
Subject: RE: [TowerTalk] AM Filter options


>
>
> It's sometimes easier and more effective to get a sharp null than broad
peak
> when DF'ing.
>
> One could null the interfering station, rather than try to peak the
desired
> station.
>
> That might be worth a shot.
>
> 73,
> dale, kg5u
>
>
> >
> > Also depends on direction.  (This is really implied in the
> > strength comment that Tom made) You may be able to use a
> > directive antenna towards the station you are interested in,
> > beverage or shielded loop, etc., as long as the undesired
> > station is not in the same direction.
> >
> > 73, John
> >
> > In a message dated Mon, 1 May 2000  2:47:10 PM Eastern
> > Daylight Time, "Tom Rauch" <w8ji@contesting.com> writes:
> >
> > <<
> > > I was wondering what options would be available to filter
> > out one adjacent
> > > AM broadcast radio station from another.  In this case
> > reception from one
> > > about 60 miles away is desired, but a second one on a close
> > spacing is
> > > causing some overload of the receiver.  Frequencies are
> > both around 1200
> > > KHz.  Thanks for any ideas.
> >
> > The problem you have and the solution depends on how the
> > frequency difference and strength difference between the stations.
> >
> >
> > 73, Tom W8JI
> > w8ji@contesting.com
> >
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