Troubleshooting a Bloodhound Cellular Connection or GPRS Modem Problem
Sometimes the Cellular Connection that the Bloodhound makes to a digital cell provider can
be disrupted by some sitiation or another. This article coveres how to troubleshoot a
scenario where your cellular connection has stopped functioning.
PREREQUISITES:
1) You need to be on-site with the Bloodhound.
2) You may need a small pair of needle nose pliers or a small adjustable wrench to remove,
inspect and re-tighten the coaxial cellular phone connection.
3) You may need a Philips-Head screwdriver to open the Bloodhound if you need to open the
Bloodhound to inspect the internal connections.
HOW-TO:
1) Check the diagnostic panel...it's in the lower-right hand corner of the display
in the field that is "rotating" through a number of values:
a) Wait for the "RSSI" value to appear and note the number (%) it reads.
An RSSI of 20% or above is generally sufficient to make a connection.
Less than 20% and you have too low a signal for the Bloodhound to
operate over the cell/data connection. Typically, if you can talk on
your cell phone while looking at the Bloodhound you will not need a
booster. NOTE: If your RSSI number is low:
i) Try moving the cell antenna attached to the Bloodhound a foot one
direction or the other. Simple structural interference can have a
dramatic impact on the RSSI number.
ii) Try moving the antenna higher. A higher antenna will reach out
farther and with a stronger signal. A simple move from the top of
a trailer to the top of an AC compressor has shown significant
positive results.
iii) Consider using an "antenna ground plane". Simply either make sure
the antenna has a flat metal base to which it is attached, or add a
12" X 12" steel plate to the base (the larger the better). This has
the effect of increasing an antenna's range.
iV) Check for ground faults in the antenna line. If you have an antenna
line routed through a trailer wall, or through a window, this is a
common problem. To check for this, disconnect the antenna from
the Bloodhound and place an AC Volt meter between the antenna
ground and the Bloodhound antenna ground. There should be very
little voltage difference. If there is a difference, you have a ground
fault. NOTE: A high AC voltage will cause damage to the Bloodhound
modem and/or motherboard.
v) You can optionally add a 3 watt booster
in the antenna path (available at most Radio Shack and cell phone
accessory stores). This can add about 15 miles of range with a
good 3db antenna. A Yagi antenna can reach up to 25 miles.
NOTE: You should always keep in mind that you should NEVER
power up a booster without an antenna attached because damage
WILL result to the booster.
vi) NOTE: While the RSSI is a good
indicator that the Bloodhound can make a connection, it only signifies
that there is a cell phone antenna within reach of the Bloodhound's
modem, and not necessarily an AT&T carrier (the default provider for
the Bloodhound) speficially.
b) Now check the same field and wait for the value of "MODEM" to appear.
It will generally appear with a couple of code letters after it and possibly
a number.
i) The value of "MODEM CN" means that the modem is connected and
working properly.
ii) The value of "MODEM NC" means that the modem is connected to
the cellular network, but not to the Bloodhound server. In this case,
you may need to contact Bloodhound Support and indicate this
situation so that they can have the listening service on the web
server restarted.
iii) The value of "MODEM NONE" indicates as physical fault that keeps the
Bloodhound from communicating with the Cell/Data modem. There are
three things to try in this case:
-Try rebooting the Bloodhound. This simple step has been known to
correct this issue in the past.
-Look at the value of Register 14 and make sure that it is set to
one (1), which means "modem aware". If it is set to zero (0), the
Bloodhound will not even try to power on the modem.
-You can open the Bloodhound's front cover and check for loose
wires/connectors (see step 4 below for more information on this).
iv) NOTE: The number is a "countdown timer" to the Bloodhound's next
attempt to connect via the cell/data modem.
2) Is there another bloodhound in the area that is connecting ok? If there is, but
it is not connecting, this might point to an issue with the cellular service in the
area or tower. SUGGESTION IN THIS CASE: If this is the case, wait for a
little while and see if the problem clears itself.
3) Has this bloodhound been connected before? If yes, check for any specific
known changes such as the antenna being moved, a break in the cellular
antenna line (for example from a window being closed on it to hard) and other
similar situations.
4) To perform internal diagnostics first open the Bloodhound case by removing
the 4 screws on the front panel and lifting the panel up and back toward you
when standing directly in front of the Bloodhound:
a) Locate the modem inside the Bloodhound (you can find it by tracing the
outside COAX connection to the modem):
b) Inserted in the modem is a Cellular SIM card. Sometimes these can become
loose during shipping and/or jostling of the Bloodhound. Ensure that this is
properly inserted and seated. OPTIONAL: If you have a SIM card phone,
you can try the SIM card from within the Bloodhound in that phone to see
if you can make a call to verify SIM card validity.
c) Observe the light on the modem itself for a few minutes:
i) Solid Green indicates that the modem is connected.
ii) A blinking Green light indicates that the modem in unable to sync to
a cell phone tower. This is most likely a problem with the antenna.
iii) If the light is off, the modem is not functioning. If this is the case
or if you have reason to believe there is a loose power connector
or other wire, check all of the connections and possibly even
disconnect and reconnect them in an effort to get the modem
on-line. NOTE: This will be the case if you see "MODEM NONE"
in the rotating field noted in step 1 above.
d) Check the internal cell phone antenna connections from the outside port
of the Bloodhound to the cell/data modem and make sure they are tight.
5) Double-check the external and internal antenna connections. NOTE: The
antenna's external connector has a double-collar connector, and sometimes
the act of tightening the main collar to the Bloodhound's port will loosen the
secondary collar. This is worth checking out.
6) Re-write the configuration to the modem (Register 55, set 1, register 123, set 1)
NOTE: WHen settting register 123 to 1, do this with the lid off and watch that
the modem resets (lights go off/on). If you need help on how to read and set
registers on the Bloodhound, see the section below titled, "OTHER ARTICLES OF
INTEREST". YOU MAY NEED TO REBOOT THE BLOODHOUND AFTER SETTING THIS
REGISTER IN ORDER FOR THE RESET TO TAKE EFFECT.
7) Prepare to escalate to Bloodhound Technical Support:
a) Note the value of Register 55 from step 6 above and write this down.
b) Check Registers 114 through 119 (Octets of the IP) write the values located
in these registers down all down.
c) Call Bloodhound Support with these numbers: Explain that you want to verify
the Bloodhound's assigned Internet IP and Port against the Master Serial List
and give them these numbers.