ADVANCED AIRCRAFT ELECTRONICS, INC

 http://www.advancedaircraft.**com/ <http://www.advancedaircraft.com/

 Does any body have any experience with this antenna mounted in
 the wing tip of an RV?

 A regular whip antenna can have as much as 3 pounds of drag at 230 MPH
which
 translates to a HP requirement of about 2.3 HP. That is a fuel burn of
about
 1.2 pounds an hour or about .2 gallons an hour.

 "Advanced Aircraft Electronics Inc. (AAE) offers a series of aircraft
antennas
 specifically designed to be used without a ground plane.  This means that
 composite aircraft and fabric covered aircraft can now have their antennas
 mounted totally within the structure. "

 Paul Lamar

 Paul,

I do not have experience with these antenna,but I heard they are really
good.They are called Bob Archer antenna after the designer.You can google
Bob Archer antenna for more info.They have them at Air craft Spruce for a
cheaper price.I believe they also have these antenna for metal air craft.I
think I might have one installed inside the Horizontal stab.  of the KIS
Cruiser,do you remember the cable that was sticking out of the horz.  stab.
that we did not know what was it for,I believe that might be for this type
of antenna.I have to take the horz.  stab.  to the airport and connect the
cable to my hand held radio to see if that is true.


Michael Hart



A protruding antenna on the wing tip will cause yaw which will have to be
compensated for causing additional drag. Not a good idea.
Rolland Lapelle



I goes inside the composite RV wing tip.

I just got mine and it looks good with wide conductors.
Wide conductors widen the bandwidth which lowers the VSWR
at the extremes of the VHF frequent range.

Here are some pictures of it.
The conductors become more or less straight when installed in
the composite wing tip.

BTW I also ordered some RG142/U low loss coax from this company.
http://www.cablexperts.com/**cfdocs/cat.cfm?ItemGroup=5&**

itmsub=0&bskt=0&c=0<http://www.cablexperts.com/cfdocs/cat.cfm?ItemGroup=5&itmsub=0&bskt=0&c=0
It should be here today.

This is half the loss per foot of some other common 50 ohm coax.
Important when the antenna is 12 or more feet away from the radio.

It is also double shielded with silver plated copper braid.

The only drawback to this apporoach is the horizontal polarization while
most VHF antennas are vertically polarized. It remains to be seen if this
is going to be a major factor. I'll let you know one way or the other.

If it works I might put the ELT antenna in the other wing tip.

Paul Lamar

The antenna does not require a ground plane since it is a dipole (i.e.,
2-pole) configuration.  In fact, the more wavelengths a dipole is physically
separated from ground, the better the symmetry of its radiation pattern will
be.  A ground plane is needed when only one side of the antenna (an end fed
antenna) is used.  Then, the antenna must be worked against a ground plane
to provide an 'image'.  The image is electrically equal to the electrical
length of the physical antenna but of opposite 'polarity'.  This is the
basis of operation for end fed vertical antennas.

A gamma match is one of many ways to perform an impedance transformation
(matching the antenna to the transmission line) between the antenna and the
coaxial cable.  The balun (*bal*anced circuit to *un*balanced circuit) is a
device that permits the use of a balanced antenna (a dipole symmetric about
its feedpoint) and an unbalanced transmission line (coax cable) or vice
versa.  If it were feasible (and in this case, it is not feasible), the
balanced antenna could be fed with a symmetric or balanced transmission line
like 'twin lead' or ladder line.  Coax is a much more workable solution for
challenging installations that require difficult routing of a transmission
line through an airframe and wing.

If a balanced antenna, such as a dipole, is fed with and unbalanced
transmission line (coax cable), the resulting bad effects include distortion
of the antenna pattern due to lack of symmetry owing to induced currents
flowing along the braid of the coax that are not equal to the magnitude of
the currents flowing on the inner coax conductor.  I have perhaps
oversimplified the scenario but it isn't black magic, although a lot of
antenna operation and theory may seem so.

I've done a lot of work with many different antenna and transmission line
types.  If this doesn't help, please ignore.

Pete Capani

Thanks Pete.

According to the instruction manual it has a balun. They claim excellent VSWR (less than two 90 to 180 mhz) over that freq. range. The instruction manual
also was very discouraging on the horizontal polarization so I decided to send
it back. The last straw was a null dead ahead just when you want to talk
to the tower.

BTW one of my early aero space jobs was an antenna technician with Melpar :)

Paul Lamar