"Как самому сделать атомную бомбу" - читать интересную книгу автора

enhanced accuracy when the bomb reaches Ground Zero.

While Frequency Modulated-Continuous Wave (FM CW) is more complicated,
the accuracy of it far surpasses any other type of altimeter. Like simple
pulse systems, signals are emitted from a radar aerial (the bomb), bounced off
the ground and received back at the bomb's altimeter. This pulse system
applies to the more advanced altimeter system, only the signal is continuous
and centered around a high frequency such as 4200 MHz. This signal is
arranged to steadily increase at 200 MHz per interval before dropping back to
its original frequency.

As the descent of the bomb begins, the altimeter transmitter will send
out a pulse starting at 4200 MHz. By the time that pulse has returned, the
altimeter transmitter will be emitting a higher frequency. The difference
depends on how long the pulse has taken to do the return journey. When these
two frequencies are mixed electronically, a new frequency (the difference
between the two) emerges. The value of this new frequency is measured by the
built-in microchips. This value is directly proportional to the distance
travelled by the original pulse, so it can be used to give the actual height.

In practice, a typical FM CW radar today would sweep 120 times per
second. Its range would be up to 10,000 feet (3000 m) over land and 20,000
feet (6000 m) over sea, since sound reflections from water surfaces are
clearer.

The accuracy of these altimeters is within 5 feet (1.5 m) for the higher
ranges. Being that the ideal airburst for the atomic bomb is usually set for
1,980 feet, this error factor is not of enormous concern.

The high cost of these radar-type altimeters has prevented their use in
commercial applications, but the decreasing cost of electronic components
should make them competitive with barometric types before too long.



Air Pressure Detonator
----------------------

The air pressure detonator can be a very complex mechanism, but for all
practical purposes, a simpler model can be used. At high altitudes, the air
is of lesser pressure. As the altitude drops, the air pressure increases. A
simple piece of very thin magnetized metal can be used as an air pressure
detonator. All that is needed is for the strip of metal to have a bubble of
extremely thin metal forged in the center and have it placed directly
underneath the electrical contact which will trigger the conventional
explosive detonation. Before setting the strip in place, push the bubble in
so that it will be inverted.

Once the air pressure has achieved the desired level, the magnetic bubble
will snap back into its original position and strike the contact, thus