The
main reason is low battery.
Pagers will alert the wearer if the battery is low. Quite often this
is in the early hours of the morning. Battery voltage is dependent
on temperature. It drops as the battery temperature drops. So in the
coolest part of the day the battery cools dropping the voltage to
below the safe operating level and so it will set the battery alert.
This problem is most predominant in tone only pagers. Display pagers
will often indicate low battery on the screen so the wearer is aware
of the type of alert.
Solution:
Arrange regular battery replacements before the battery level drops too
much. In general a pager should operate for 4 weeks. Monthly replacements
should eliminate the problem.
When replacing batteries
always ensure the battery is an alkaline battery. Only these types can
supply the current demands of a pager. Be wary of cut price batteries as
these may have poor shelf life.
This is a difficult
question to answer as there are many factors that influence the
pager coverage area. The two main areas to consider are the
transmission and the reception properties.
The transmission is
optimized at installation time and is based on the layout of the
station where the paging transmitter is located and the
requirements of the pager wearers and were they spent the bulk
of their time. These properties are stable and very rarely
change but changes do occur. A good example is where an antenna
located at the Boonah Fire Station was hit by lightning but
continued to operate perfectly. A hole in the radom (the white
fiberglass outer shell) caused by the lightning eventually
allowed rain to seep into the radom. After two years the base of
the antenna rusted and slowly degraded the effectiveness of the
antenna.
Transmission factors:
The most obvious is the
terrain. There are some sites where the topography is quite flat
and the pagers work up to 20-30 kilometers from the station.
There are other sites where it only works 1-2 kilometres.
The height of the
antenna is the next most important factor. Obviously the higher
the better. In general a height of 60 feet or higher is best.
Reception factors:
The battery level will
affect the pager sensitivity. Do not wait for the pager to
indicate it has a flat battery. In some pager models we tested
the sensitivity can drop by half when the battery is near the
flat battery alert level.
Man made objects such as
sheet metal enclosures such as garages, sheds, walk in fridge
freezers, lifts etc all cause the reception to be diminished.
Water. Pagers and water
do not mix. This includes moisture from bathrooms.
Any type of physical
abuse can degrade the pager sensitivity. Pagers do not work
perfectly or stop. There can be many levels of degradation.
Taking all these factors
into consideration the best way to check reception is to do
regular weekly checks at distances greater than a few kilometers
from the transmitter.
There are now Adobe .pdf
available to view for the latest pagers user guides.
click here to view Pager User
Guides
There are nearly always
three letters then a full colon at the beginning of every message
you receive and its called a Pcode. A Pcode indicates
where the pager message was transmitted from. e.g. if you were
to receive on your pager "TUL: Test
message" then the message came from the Mt Mackay transmitter
near Tully in North Queensland. There is a Pcode for every site
in Queensland. If the message was sent by the Orange or
Hutchison network then either a H: or HUT: pcode will appear.
click here to see
Pcode List
There are many messages
generated by the picocell. In these examples it will be messages
for the Airlie Beach picocell.
These messages are only
delivered to the captain and lieutenants. If there is no
separate captains pager then the auxiliary group will receive
the message.
If no one receives these
message below then advise MTEL immediately. The messages are
fault conditions which if not attended to can be detrimental to
the turnout capability of the picocell.
The most likely one to
receive is power failure indication. This will occur after about
70 seconds from the loss of mains power. Shorter breaks will be
transparent to the picocell.
The message should read;
AIRLIE
BEACH PICOCELL LOSS OF MAINS POWER
When the power is
returned the picocell will page immediately;
AIRLIE
BEACH PICOCELL MAINS POWER RESTORED
As a general rule it is
not a bad idea to try this on training nights. Turn off the
picocell at the mains power point for about two hours then turn
it back on. Both messages should be received.
During prolonged power
outages you may receive a message;
AIRLIE
BEACH PICOCELL BATTERY FLAT: Operational failure is imminent.
In this case the power
has either been absent for a very long period typically greater
than 8 hours. The battery is becoming exhausted and will
requiring charging soon.
This message will also
be generated if the battery life is near exhaustion. Typically
these gel lead acid batteries last from 3 to 5 years. What
promotes the destruction of these batteries is extreme heat and
cold, over charging, under charging or several deep discharges >
12 hours.
If the picocell is to
endure long absences of power than a generator can be used to
keep the picocell running. Typically one hour running every 6
hours will keep the battery charged sufficiently.
If the battery has been
discharged to the point above, then when power is returned a
message will be generated;
AIRLIE
BEACH PICOCELL BATTERY OK
This means the power
supply has started and the battery is recharging.
Up to now all the
messages relate to power conditions in the picocell.
The next message is due
to the communications between the Firecom Centre and the
Picocell. If the communications during a turnout has been
disrupted the picocell will after 70 seconds reset it self
internally and generate the following message;
Warning:
Picocell has cleared an internal fault: PET timer expired
This is simply a
warning. It says and internal communications protocol (Page
Entry Terminal protocol or PET for short) timer has expired.
That is the communications did not complete as intended. It has
simply reset all the internal timers and variables ready for the
next turnout.
It pages the captain so
that if it occurs more than once every six months, then there
could be a problem. If this message is generated always contact
MTEL.
There is a similar
message to the last one but it is extremely rare and means the
system has actually locked up internally then cleared itself.
Warning:
Picocell has cleared an internal fault: BUS timer expired
Once again if you get
this message advise MTEL immediately.
The picocell will also
generate alarm messages however these are tailored to the
picocell site. You must contact MTEL to confirm what these
messages will be.
The battery should last
12 hours without mains power.
What can influence the
life of the battery are the age, state of charge in the last 12
hours and the amount of paging use while in battery mode.
If the picocell is going
to experience power outages for known periods such as
maintenance then a generator can be used to keep the picocell
operational. Typically one hour running every 6 hours will keep
the battery charged sufficiently.
The age of the battery
is normally marked or scratched into the front face. If not
advise MTEL as we may have records of the last change.
MTEL has a maintenance
program that replaces all batteries inside 3 to 5 years of age.
Currently there are
three types of pager numbers in a picocell.
The "Auxiliary"
or "Turnout number" is in every picocell. It is the
number that pagers all the auxiliary fireman in one instant. All
auxiliary fireman pagers will have the same number. The number
though is different in every picocell so that neighboring
picocells will not affect each others auxiliary groups.
The second type of
number is the "Captains number". As the name suggests it
is just for the captain. There are some auxiliary groups though
that have lieutenants as well and sometimes these fireman are
also on the captains group number. Nearly every site has a
captains number. If you do not have a captains number then
contact MTEL.
Finally there is the "Messaging
number". This is only used where picocells are connected to
the local alarming equipment. Some alarming equipment will
activate the siren if the auxiliaries do not attend the station
in a predetermined time after a turnout message has been sent
from Firecom. However not all messages sent to the picocell are
for turnouts. Some are just general messaging such as a change
in time for training. In this case the messaging number is used
by Firecom rather than the turnout number to avoid activating
the siren sequence.
