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Old 10-07-2008, 08:36 AM   #1
Saico
Avalon Senior Member
 
Join Date: Sep 2008
Location: Netherlands
Posts: 4
Default New facts about emp

================================================== ============
NEW FACTS ABOUT EMP
BY R. KENNETH MITCHELL, KA6FRD

The National Communications System (NCS), a governmental entity
made up from 22 different Federal agencies, wants ham radio
operators and their gear to survive an EMP (Electro-Magnetic
Pulse) generated "nuclear event."

NCS engineers have simulated the EMP phenomenon in the laboratory
and have subjected various pieces of current amateur radio gear
to its effect.

The people at NCS came to some rather surprising conclusions.

In their report they say, "It was concluded that modern
solid-state amateur radio equipment was more survivable in an EMP
transient environment than had been previously anticipated."

What makes those sophisticated and delicate transistors and ICs
so survivable?

The secret is in having two EMP surge protection devices. One is
needed on the end where the power comes into the radio and the
other on the antenna end where the RF signal goes out.

The NCS tested various commercially available suppression devices
designed for both lightning and EMP and, in a move surprising for
any governmental agency, issued a report telling which ones
worked and which ones didn't.

Their findings and recommendations are outline in a 105-page
publication entitled "Electromagnetic Pulse/Transient Threat
Testing of Protection Devices for Amateur/Military Affiliate
Radio System Equipment"--otherwise known as NCS Technical
Information Bulletin 85-10.

When considering EMP protection for transient voltage spikes
coming in through commercial power lines, the folks at NCS
recommend the TII model 428 plug-in power line protector, an item
which costs only $45. But for those a little strapped for cash
(and what survivalist isn't), the report shows how you can make
one yourself for an estimated cost of only $11.

For EMP protection on the antenna side of a rig, NCS recommends
the Fisher series of spikeguard suppressors. They come in a
variety of different clamping voltages, depending on the
characteristics of a specific station.

The bulletin provides a mathematical formula to determine which
fisher model is correct for your radio.

The Fisher devices cost $55, thus giving hams total effective EMP
protection for their radios with off-the-shelf items for only
$100.

If your radio has a power output of 100 watts or less, a second
coax protector was recommended, the PolyPhaser products. They
proved to be just as effective as the fisher products but cost
somewhat more--$82.95 each. Because of their lower clamping
voltages, they are recommended only for lower wattage
transmitters.

But again, for those handy with electronics, NCS shows you how to
make a simple home-made protection device for your antenna system
for only $9.

It was interesting to note that two relatively inexpensive
devices simply did not work. The Archer (Radio Shack brand) AC
line protector was NOT recommended. Nor was the Alpha Delta
brand "Transi Trap" coax protector, commonly advertised in ham
radio magazines.

Other interesting findings made by NCS engineers were that
portable generators, such as Honda types, were not likely to be
adversely effected by EMP at all. Neither were hand-held walkie-
talkie type portable radios, particularly those with short stubby
"rubber duck" antennas.

The importance of a proper grounding system for amateur radio
stations was discussed in the report with specific recommen-
dations for maximum effectiveness.
================================================== ============
Now we need The "NCS Technical Information Bulletin 85-10".
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Old 10-12-2008, 06:15 PM   #2
MargueriteBee
Avalon Senior Member
 
Join Date: Sep 2008
Location: Northern California
Posts: 216
Default Re: New facts about emp

Do you have a link? I would like to have my electrician look at this.
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