"Free radio" wrote in message
...
does any body no why .i have seen a cross yagi type beam along the
bridge .my guess will be to monitor the water level umm maybe not
73s not really a pirate ok only on the sea


In the Illinois, I see 2 primary systems.

The cross yagi - pointed skyward is for satellite reception of the data
[southern sky - about 40 degree angle] for water levels of watersheds,
streams and rivers. You will usually see them at dams, some bridges or
confluences of streams/rivers.

The Dept of Transportation in Illinois (and many other states) have small
weather stations along the tollways, interstates and major 2 lane highways
for weather conditions throughout the state. They will have a small UHF
yagi and it not unusual to see these small weather stations high traffic
areas or bridges. Bridges allow for additional sensors to measure freezing
conditions on bridges or water levels in flood prone areas (cooperatively
sending data to NWS and other services).

The Army Corps of Engineers also has a number of stations for the Illinois
and Mississippi River watersheds, for proper control and management of the
lock and dam system above St. Louis (St. Louis, Rock Island, Omaha and St.
Paul Districts).
http://www.mvr.usace.army.mil/

Many of these gauges are cooperatively managed by the Army Corps and other
federal, state or municipal agencies, such as: USGS, NWS, universities.
This specific gauge is at the Hydraulics Laboratory (on the Iowa River) at
the University of Iowa in Iowa City, IA
http://www2.mvr.usace.army.mil/Water...fid=IOWI4&dt=S

gb