Part of what emerged from the terrorist
attacks of Sept. 11 was the need for better communications between
emergency responders. Likewise, examination of why nine Charleston,
S.C., firefighters died in a June 2007 blaze reminds us that despite the
great strides since 2001, communication remains an unsolved issue. One
emerging technology involves cutting the cord and going wireless on the
fireground. We asked Sarmad Hannosh, FireCom's senior electrical
engineer, about this technology, how it can be used by fire departments
and its shortcomings. Hannosh has worked in the fire and emergency
warning and communication industry since 1995.
Describe the state of wireless headset technology for fireground
communication. How mature is this technology?
The technology has been around for years. Though it has been utilized in
other industries, it has not been applied to the fire service until
recently. The technology allows the first responder to be virtually
un-tethered, giving the engineer and other crew members mobility around
the truck. Open-license technologies are the most commonly used in the
wireless industry, but it often is found to be not appropriate or
reliable enough for the fire and rescue industry. But there is now a
wireless headset that operates on an interference-free band that
utilizes a recognized protocol standard.
When is it right for a department to switch to wireless
communications?
The right time for departments to switch to wireless is when their
budgets allow them to purchase new headsets, when configuring a new
truck, when the department needs the engineer to be wireless from the
apparatus, or when there is a need for the chief to be wireless on the
fireground.
What is the cost difference between wired and wireless
communication?
With a new installation, one driver and one engineer configuration (no
interior or pump panel module), the difference is approximately $264.
Do wireless communication headsets have durability or longevity
issues different from wired sets?
No. In fact, the wireless headset uses the same form factor as the wired
headset. The headset’s durability and ease of use already have been
tested and proven over the years. Also, communication cords and
connectors are no longer an issue with wireless headsets. And there are
no problems with slamming the cords in the door. The battery will need
to be replaced every few years with a wireless headset. But other than
that, there are no differences between the wireless and wired headsets
except for the enhanced capabilities that a wireless headset provides
the user.
How will the reconfiguration of the 700-MHz band affect the wireless
microphones?
There should be no effect whatsoever because the wireless system is
licensed by this Federal Communications Commission.
Is background noise any different with wireless and wired
communication?
No, the wireless headset is voice activated much like the wired headset.
It has built-in noise gating to prevent background noise from breaking
through.
Will solid objects, such as walls, floors or apparatus block the
wireless signal?
Solid objects will exhibit some attenuation to the wireless signal
depending on the nature of the object (material, thickness, geometry,
etc.). Also, site topography and conditions may impact the range.
However, the wireless system provides more than sufficient range for the
intended use through carefully calculated radio-frequency power levels,
antenna design, antenna diversity, and the very nature of the chosen
protocol and operating frequencies. The wireless system has been tested
under various site conditions and proven to provide excellent
performance around the fire apparatus under these site conditions.
Are the units weather-resistant (against rain, wind, snow, etc.)?
The wireless headsets are weather-resistant within reasonable limits.
They are protected against rain (but not submersible), and they were
subjected to environmental testing for humidity, salt fogging, shock and
vibration per MIL-STD-810F. All electronics inside are conformally
coated for added weather protection.
Do they help to overcome background radio noise identified from the
Digital Problem Working Group?
No. This is a problem with the digital radio, not the wireless headset.
Are they affected by any other radio spectrum interference?
No. The wireless system was subjected to radio-frequency immunity
testing between 30 MHz and 18 GHz at 50 volts-per-meter field strength
and did not experience any degradation of performance throughout the
entire specified spectrum. It also employs the principal of existence
with similar devices operating in the vicinity.
What is their reliability to maintain connectivity?
The wireless system is very robust in terms of maintaining connectivity
within the operating range boundary. It employs antenna spatial
diversity on both ends (the fixed and portable parts). It also is
capable of automatically restoring connectivity when lost due to
exceeding the operating range.
Is there some sort of warning if connectivity is lost?
The headset will sound a nonintrusive warning beep once every 15 seconds
when on the fringes of the operating range and prior to loosing the link
completely.
What developments do you foresee for wireless communication in the
next five to 10 years?
The wireless communication system will see expanded uses in the fire and
rescue industry. As first responders adapt to the new technology, they
will demand the ease of use of the system in other areas of their
departments. Honestly, we actually don’t know all of the future uses
of this technology but over time, customers will drive product
innovations.
