Customer Service 800-528-7411 or 602-470-1414
Page 53 of 68
The Fresnel Zone is tabulated for 2.4 GHz at different distances. Recommended
obstruction should be 20% or less. This can be used as a guide to help determine how
high to place your antennas if you are experiencing radio communication problems with
the 451/651 instruments.
Range Distance
80% Fresnel
Zone Radius
1000 ft. (300 m)
8 ft. (2.4 m)
1.0 mile (1.6 km)
19 ft. (5.7 m)
2.0 mile (3.2 km)
26 ft. (8.0 m)
5.0 mile (8.0 km)
42 ft. (12.6 m)
10 mile (16 km)
59 ft. (17.9 m)
The basic rule is to make sure that the combined height of the base station and
instrument antennas is greater than the radius of the Fresnel Zone.
Buildings and trees in the Fresnel Zone can also block a portion of the signal. Trees are
a particular problem for 2.4 GHz radios. Although 2.4 GHz signals can pass through
walls, they have a harder time passing through trees due to the water content.
Occasional communication errors due to interference are normal in urban areas or in
bad weather. The Jerome 451/651 instruments store sample data until the radio is clear
enough to send it.
15 FLOW PUMP KIT
A Flow Pump Kit (P/N Y990-0195) is available for the 651. The Flow Pump Kit has the
ability to draw air for sampling over a
long distance and still provide
continuous real-time readings.
Contact your Technical Sales for
more information.
Line power of 100-240V AC, 50/60
Hz must be run to the marked
connections of the terminal block in
the flow pump. Maximum current
draw is 1 Amp.
