Campbell Com100 Instruction Manual - 4. Power Considerations
COM100 Cellular Phone Package
4
ASPD912M Trunk Mount Antenna
Gain:
3 dB
Frequency:
806-869 MHz or824-876 MHz
Bandwidth:
60 MHz @ 1.5:1
75 MHz @ 1.9:1
Impedance:
50 ohms
Height:
24"
ASPD913 Mirror or Side Body Mount Antenna
Gain:
3 dB
Frequency:
824-896 MHz
VSWR Max
1.9:1
Impedance:
50 Ohms
Cable/connector:
17 ft/Mini UHF
ASPD955 Vertical Base Station Antenna
Gain:
3 dB
Power:
500 W
Freq:
806-896 MHz
VSWR Max:
1.5:1
Termination:
N female
*From Allen Telecom (800) 321-9977
Decibel Products (800) 676-5342
4. Power Considerations
The relay included with the cellular phone power control cable allows the
datalogger to switch power to the cellular transceiver. Even so, the relatively
high current required by the cellular transceiver makes it necessary to use a
solar panel, vehicle power system, or AC power to maintain a charge on the
system battery. It is unfeasible to power the datalogger and transceiver from
batteries alone unless the battery capacity is very large, the batteries are
changed frequently, or the transceiver is switched on infrequently.
Since a battery is simply a storage device, a power budget can be calculated to
determine the battery capacity required per day using the following equation:
(standby current drain)*(time in standby mode) + (on-line current drain)*(time
on-line) = Total Amp-hours required
A common application is to turn the transceiver on (in stand-by mode) for 10
minutes at the top of each hour for a full day. This allows ample flexibility for
a user to perform operations such as data-collection, real-time monitoring, new
program downloads, or clock sets. In this example the transceiver was on-line
for 15 minutes of the day to perform the tasks listed above. The Amp hour
usage per day can be calculated as shown in this example:
On-Line time
15 minutes
(0.25 hrs)/day
Stand-by time
225 minutes
(3.75 hrs)/day
Total Time
240 minutes
(4.00 hrs)/day
(0.25hrs/day) x (1.8A) + (3.75hrs/day) x (0.17A)
≈
1.0 Ahr/day