Sender: <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Sun, 23 Mar 2008 07:49:16 -0400
Message-ID: <redirect-2814264@logan.com>
From: "Paul Bricker" <pbricker@att.net>
References: <list-2813820@logan.com>
Subject: RE: [LML] Re: Miracle Antenna/AirWhip
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Angier,

Let me start by saying I don't have any experience with the AirWhip =
antenna.
I am an electronics engineer (retired) and Ham.=20

If I read the AirWhip description correctly it appears to be a network =
that
end-feeds an antenna element that is the length of a dipole, eliminating =
the
need for a ground plane. I have no doubts that it does that, and the
impedance match is good. That said, I see some issues.

1) The antenna needs to be oriented to match the polarization of the =
signal
it is attempting to receive or transmit. For VHF voice that is vertical
polarization, and for VORs that is horizontal polarization.=20

2) The antenna length need to be 1/2 wavelength long to get the best =
gain.
That=92s about 54 inches for the bottom of the Nav band and 50 inches =
for the
bottom of the Comm band.=20

3) The antenna element needs to be close to straight to achieve maximum
gain, so it shouldn't be wrapped inside the empennage (for instance). =
While
composite planes can usually find a 55 inch horz location of an antenna
(wing, belly, etc.), and vertical location is more challenging. That's =
why
the Archer dipole antenna is usually bonded inside the vertical =
stabilizer.
It's the only location that supports the physics of the situation.

On the positive side, the connection appears much more substantial than =
the
center feed for the Archer dipoles, and from that standpoint it could be =
an
improvement.=20

The site doesn't say what type of coax pigtail extends from the AirWhip. =
If
it's just RG-58, or some other single shield coax, the pigtail should be
shortened, a new BNC installed, and the remainder of the run done using
RG-400, or some other high quality 50-ohm double shielded cable.

Hope this helps

Paul Bricker
N63PB

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
Greenbacks, UnLtd.
Sent: Saturday, March 22, 2008 6:40 PM
To: lml@lancaironline.net
Subject: [LML] Re: Miracle Antenna/AirWhip

Is there anyone on the list with knowledge of, or experience with this =20
product?
Looks interesting...

http://www.miracleantenna.com/AirWhip.htm

Angier Ames
N4ZQ


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