During the post WWII era, there were some notable radar returns
from unidentified sources. For instance, in Japan, on November 6, 1948,
Air Force operators tracked two strangely maneuvering objects for
sixty five minutes. It remains a mystery.
In 1950, Naval officers at Key West reported two glowing objects
had been tracked by radar men as they streaked above the air station.
They were also seen by pilots and ground men, flying at a height too
great for attempted pursuit.
Radar operators are trained to identify the speed of tracked objects,
and UFOs have been regestered between hovering, and even speeds
of 10-12,000 mph. Such extreme events can not be accounted for by
simple anwers using weather conditions or birds, especially complicated
moving targets.
In order not to be seen by radar, an object would need to be transparent to,
absorb, or refract (bend) or reflect away radar signals. If a radar signal
strikes a surface, and if that signal is reflected at an angle beyond the
threshold of the recieving antenna, that signal will escape detection.
Thus, flat, direct targets are ideal. But even a round surface can have
some section exposed for a good signal.
As to what may also affect microwave signals, materials embedded
into the surface of a target can reduce radar return. It has been
known for fifty years that iron particles, suspended in an elastic matrix,
or even paint, can behave as a resistor. When magnetized and
configured in a manner, in can create around 377 ohms resistance,
impede, and essentially dissipate an incoming radar signal.
Surfaces inside of planes and on the decks of ships are are many
times coated with a rubber material, like neoprene, which has embedded
iron or some suitable resistor substance. This protects surfaces from
high energy microwave damage, and reduces clutter information
on the display screen.
Radar is a sophisticated technology, and always has been complex
to operate. There are echoes that return unwanted information,
and it sometimes gets misinterpreted. But, not for long.
Especially if there are multiple radars in a locality, reporting
the same unidentifiable signatures. It gets even more complex
with visual confiramation and numerous witnesses independently
observing a UFO.
I have wondered myself about the effects of certain ionized field
effects, and what they may do to radar. The Russians claim to
have a lasar that would emit pulses foward of a military aircraft,
and it in turn would ionize a small quantity of atmospheric atoms (N, O),
which would spread out along the jet, as it moved forward.
A charged tailpiece would capture the drift ions, and thus envelop
the aircraft with this thin field. The claim is that it bends, or refracts
incoming radar.
If you think about it, it is like the old machine guns on a bi-plane.
To shoot through the propellor, a timing mechanism was connected
to the gun. Aircraft rely on their own radar for protection.
If you block radar, you send none out, either, and become blind. So,
a burdensome construct of computer software and
relays become needed to get down to mirosecond bursts of
outgoing radar, with sensors to recieve the approriate return.
It can be done, using gas filled antennas, which turn on and off
like flash-flourecent bulbs.
The problem is in the ion stream around the plane, per the russian claim.
If you travel too fast, what happens to the stream? If you cannot
generate a really powerful retention field, you lose the ions like
any other airstream.
But, UFOs have been reported to have glowing plasma-like
or photoionizing fields around them, yet they were seen on radar.
Again, it depends on the polarisation and strength of any
radar signal, as to its possible interaction with an electro-
magnetic, electro-static, or some ionized field, or a even a
more intensly ionized plasma induced ion field. Plasmas are heavily
ionized, and while typically associated with high electron or ion energy
they can and are produced at room temperature. They could,
if dense enough, deflect, bend, and scatter a short photon wave
like a microwave.
So, a microwave radar has 3 polarized aspects-
horizontal, vertical, and circular. And various energy levels.
And, the number of pulses sent out can vary per minute.
These, the distance to the target, its composition, and shape of its
surfaces will affect the outcome of any return signal.
To add to detection possibilities, one may look at other signatures,
as well. For instance, heat or thermal emissions can be tracked.
And, non-radar reflecting surfaces may be identified, nonetheless,
using 'ladar', or laser energy.
Another method of detection is called passive disturbance.
This is when you set up a grid of radio towers, and broadcast
certain radio frequencies (1-2 GHz), so as to set up a network
of detectors. A disturbance in the field would identify a flying intruder's
position. They should be detected even if they elude radar.
As to intentions, and allowing oneself to be locked onto
with a radar signal, and one's abilitites to control
that every minute, at both ends- becomes conjecture.
I wager some unusual radar events have happened.
Even outright jamming of radar stations has been reported.
That is not safe for either civilian or military airports, but
it has been reported a few times, regarding UFO events.
http://www.af.mil/media/photodb/photos/021...O-9999G-007.jpghttp://www.randf.com/ramapriaas.htmlThe microwave portion of the Electromagnetic Spectrum is quite large,
relative to the visible, and there are several wavelength ranges or bands commonly used in radar imaging. Usually, only a portion of that is used
in airport radar, but military or civilian aircraft can probably emit a
range of signal from 2.7 - 15 GHz.