Dr. R. Alan Kehs
Army Research Lab
Joint Economic Committee
United States Congress
Wednesday, February 25, 1998
"The Radio Frequency Weapons Threat and Proliferation of Radio Frequency
Mr. Chairman and Members of the Committee, I thank you for the opportunity
to help shed some light on the widely ignored topics that you have chosen
for these hearings. I have spent most of the last twenty years working
on various radio frequency weapons technologies and I am currently serving
as chair of the tri-service High Power Microwave (HPM) technology coordination
In general, our security classification guide prevents us from discussing
anything but the most generic concepts and severely limits the depth of
discussion if we remain at the unclassified, full public release level.
It is not deemed to be in our best interests to provide details on our
programs or roadmaps to weapons development that might assist rogue states,
terrorists and others who would eventually wish to use these weapons against
However, one does not need to rely on classified reports in order to appreciate
the potential impact of radio frequency weapons (RFW) or as they are frequently
called, HPM weapons. Everyone in this room has undoubtedly experienced
Electromagnetic Interference (EMI) to some piece of household electronics.
Some common examples are the effects of lightning strikes or automotive
ignition noise on radio transmission, placing two computers too close
to one another on a bench, driving under power lines while trying to listen
to the radio, and so forth.
A step up from these minor inconveniences is the warning that we hear
each time we take off or land in an airplane. We all wonder "can a Gameboy
or calculator really cause serious problems to the airplane electronics?"
The answer, of course, is that a Gameboy, calculator or cellular telephone
is not usually sufficient to disrupt airplane electronics, but it can
happen. As a result, we adopt a policy of "better safe than sorry" and
shut down electronics during the more critical take off and landing segments
of commercial air flights. We have now asked the question "How much power
does it take to create problems?" Realistically, these questions cannot
be answered at the unclassified, full public release level. More subtly,
the question becomes "At what point do common civilian electronic devices
Let us shift now from the low power levels (microwatts and milliwatts)
of gameboys and cellular telephones to the very high power levels (megawatts)
of commercially available radar systems, TV transmitters, and particle
accelerator tubes. This is the platform from which HPM weapons programs
would be based.
Conceptually, an HPM weapon looks like a radio transmitter. There is a
power source, a tube to generate RF energy, and an antenna to radiate
the energy appropriately. The key technologies and final products have
been under development for the greater part of this century and are readily
available on a broad range of markets. In the Army, we make extensive
use of surplus radar and radio equipment.
Military electronics generally contain some electromagnetic shielding
and protection devices -- even if they are not specifically designed to
withstand an HPM attack. Commercial designers are generally concerned
only with FCC limits on EMI and no one knows how susceptible commercial
electronic systems might be to a concerted electronic attack. These commercial
systems include our banking and telecommunications systems as well as
oil and gas distribution and transportation systems, among others. Although
these systems are designed to withstand the loss of a critical node, a
concerted attack would cause unknown effects.
HPM technologies appear on the critical technologies list. However, the
required special approvals have not slowed the transfer of increasingly
powerful and sophisticated HPM technologies to overseas buyers.
The intelligence community will have to address the threat issues but
I believe that they will find existing technology is more than sufficient
to support several potential applications and threat scenarios.
The growing US dependence on sophisticated electronics for warfighting
and domestic infrastructure makes us potentially vulnerable to electronic
attack. By its nature, the Defense Department is compelled to confront
such threats, however, the full range of our technological society is
also at risk and much less aware of potential threats. I pray that congress
will help all of its agencies and departments to appreciate the increasing
seriousness of the questions raised here today and take appropriate actions
to evaluate threats and construct appropriate defensive measures.