IMPROVED
PINGERS FOR EXTENDED SUBMERSION
A
major improvement in acoustic pingers dramatically extends the
time these devices can be relocated
after their deployment. Pingers are most commonly used
to mark the location of an underwater site or anchored
instrument package. By
constantly transmitting an acoustic signal, the pinger can
quickly and easily be located using a hand-held pinger
receiver. The improvement is a delayed start mechanism which
allows the pinger to postpone the start of its acoustic
transmission from a minute up to 99 days.
This feature is extremely valuable when marking sites
that may not be revisited for months at a time. During
“sleep time” the pingers draw a very small amount of
power, significantly increasing the life of the batteries.
The
delayed start is available on Fishers single frequency and
multifrequency pingers. The
single frequency pinger (SFP-1) transmits only one frequency.
The user selects one of four transmit frequencies at
time of order. The
multifrequency pinger (MFP-1) allows the operator to select
any of 60 different transmit frequencies in the field.
Both models of pingers allow the operator to select the
number of pings per second, the amount of time each ping
lasts, and the output power.
These parameters determine how long the pinger will
operate and how far away it can be detected.
Power is provided by internal 9 volt batteries.
An extended housing is also available to allow more
batteries to be installed, which can triple normal operating
time.
Pingers
are being used by a diverse group including scientists and
military units around the world.
Scientists often use pingers to mark the position of
underwater instruments such as current or salinity gauges, but
other applications are quite unique.
Researchers at Lester Pearson College in Victoria,
Canada are using Fishers pingers to mark the location of a
number of metallic samples anchored to the ocean floor.
Says spokesman Chris Blondeau, “We are conducting
tests on the corrosion resistance of a variety of materials.
Those with the best resistivity will be used in the
construction of underwater housings and various instrument
packages.” And the military frequently use pingers to identify the
location of mines or other unexploded ordnance, but they’re
not the only ones interested in finding these devices.
In Italy, the Societa Explosivi Industriale, a
government group charged with finding and disposing of
explosive devices, is using these pingers to mark unexploded
ordnance discovered during marine construction projects and
harbor dredging.
In
addition to their complete line of pingers, Fishers also
manufacture the PR-1 pinger receiver which can locate any
pinger transmitting a frequency between 3 and 97 kHz.
When the receiver is tuned to the desired frequency and
pointed in the direction of the pinger an audio alarm sounds
and an LED light bar flashes indicating the pinger has been
located. A
compass on top of the PR-1 guides the operator directly to the
site. As the receiver gets closer to the pinger, the audio
signal increases and more LEDs are illuminated.
Fishers
pingers and pinger receiver, and all of their other underwater
search systems, are covered by a two year warranty.
For more information on these products or a brochure on
their complete line, call (800) 822-4744, e-mail - jwfishers@aol.com,
or visit the website - www.jwfishers.com.
