Ramsey Electronics FM10C Manual page 29

METERS
cause interference to broadcast reception.
"Why talk about acres"?
There are three reasons to translate our look at "field strength" into "acres".
(1) The first one is easy: the numbers would get too cumbersome if we
discussed your possible signal coverage in terms of square feet or
square meters.
(2) It's very easy to see that your signal can easily and legally serve a
school campus or wilderness campground.
(3)And, if we remember that typical urban single-family home sites run
from 1/4 to 1/2 acre on the average, it should become extremely clear
that your obligation to avoid interfering with broadcast reception can
easily involve hundreds of homes, before adding apartments!
In fact, the most significant distance in the above chart is the 1.9 µV
signal strength permissible at 1260 feet (about 1/4 mile), covering a cir-
DISTANCE FROM TRANSMITTER ANTENNA
3
6
12
24
48
96
192
384
768
1536
FEET
STRENGTH
10
20
39
78
157
315
630
1260
2520
5036
FM10C 29
FIELD
RECEPTION
(µV)
250
125
63
31 19113 FT
15 1.8 ACRES
7.5 7.2 ACRES
3.8 28.6 ACRES
1.9 114 ACRES
.95 458 ACRES
.5 1830 ACRES
TOTAL
AREA
314 FT
1256 FT
4800 FT