SECTION 2. ASSEMBLING THE RADIOTELEMETRY NETWORK
2-3
1. Tripod or tower
2. Enclosure and datalogger - Turn on
datalogger.
3. Antenna - Orient correctly; remember
direction and polarization.
4. Solar
Panel
5. Power
Supply
6. Sensors
7. RF Modem - Set the Station ID according to
the map.
8. Radio - Make sure to connect to RF Modem
and to power supply. Connect to antenna
before turning on.
2.4 TEST THE RADIOTELEMETRY LINK
With a field station or repeater installed, return
to the base station for initial testing of the
communication link. An RF link can also be
tested at the field site with a portable base
station; hardware requirements for the portable
base station are described in Appendix B.
At the computer site, start NetAdmin. Select RF
LINK TEST found on the VIEW menu. It is not
necessary to add the field station or repeater to
the net description to test the communication
link. As before, select the RF base in the upper
left box. Move the cursor to the [REPEATER]
SWITCH SETTING box. Enter the ID for the
remote site as set with its switches. Select the
BEGIN button. If the test is successful the
signature of the remote RF95T PROM along
with the quality numbers will be displayed. The
test may take several minutes to complete. The
quality numbers should be examined as they
will help indicate potential problems like outside
interference on the frequency or marginal links.
These numbers are explained in Section 2.7.
2.4.1 A SUCCESSFUL TEST
After a successful test, set up the next nearest
site and test that telemetry link. If a repeater is
to be utilized to communicate with a site, enter
the ID of the repeater followed by the ID of the
field site in the [REPEATER] SWITCH
SETTING box. Separate the ids with a space.
When the BEGIN button is selected the entire
link will be tested. The signature of the remote
site will still be returned. An additional row of
quality numbers will be returned for each
repeater.
2.4.2 AN UNSUCCESSFUL TEST
If the base cannot communicate with the
remote, a TEST FAILED message will be
displayed in the TEST STATUS/RESULTS box.
For links not using a repeater, the problem
could be at the base or the remote site. Section
2.5.1 gives some suggestions that can be tried.
For links utilizing repeaters, start by testing the
link between the RF base and the repeater. It is
not necessary to have a datalogger at a
repeater site to test communication with the RF
TEST LINK. As each part of the link is verified,
add the next segment and test again. With this
method it should be possible to determine which
segment is failing.
2.5 TROUBLESHOOTING UNSUCCESS-
FUL COMMUNICATION ATTEMPTS
2.5.1 TROUBLESHOOTING PHYSICAL LINK
BETWEEN BASE AND REPEATER/FIELD
STATION
When communication is not established,
troubleshooting begins with the simplest RF link
in the system, which is usually communication
with the nearest field station. There is NO
substitute for first checking the hardware
connections, Station IDs, and everything listed
in the previous sections. Below are a few
additional items to check:
1. Antenna is used in proximity of metal.
2. Transmission from inside a building.
3. Damaged or shorted cables.
4. Bad or improper connections.
5. Antenna frequency does not match the
radio frequency.
6. Base and field station radios aren't using
same frequency.
7. Datalogger power drops below 9.6 Volts
during RF transmission. Use datalogger
Instruction 10 or volt meter.
If the field station's RF95T Modem's Carrier
Detect light goes on during a test, then at least
a signal is reaching the site. If this occurs,
check the following:
