[BC] Poor Reception Areas

[Urban, Brian L]

70 dBu (dB above 1 uV) = 3.16 mV/m
60 dBu (dB above 1 uV) = 1 mV/m
57 dBu (dB above 1 uV) = 0.7 mV/m
54 dBu (dB above 1 uV) = 0.5 mV/m

The engineering charts in 73.333 are used to predict received signal strength; F(50,50) for desired signals, F(50,10) for interfering signals.

     The F(50,50) chart gives the estimated 50% field strengths exceeded
   at 50% of the locations in dB above 1 uV/m. The chart is based on an
   effective power radiated from a half-wave dipole antenna in free space,
   that produces an unattenuated field strength at 1 kilometer of about
   107 dB above 1 uV/m (221.4 mV/m).

The F(50,10) interfering signal curves are 50% of locations 10% of the time.  Those curves are based on actual measurements made in the early days of radio.  If you have ever tried to take FM field strength measurements, you know what a crock of bull those curves actually are.  See 73.314 for the accepted procedure.  Check your credulity at the door.

--
Brian Urban
Chief Operator
KUT Radio
TEL 512-471-1085

On 2/22/10 4:19 PM, "Jason R. at KGVL - KIKT" <jyrussell at academicplanet.com> wrote:

>45-50+ is pretty low, and you'll start getting trash and picket fencing as
>you drive along.
>60+ works, but you'll start noticing some noise in the signal.
>I *think* 70 dbU is a city - grade.  Gets inside most businesses with a
>useful signal.
>80+ ish oughta sound pretty decent.
>90+ should drive a receiver into quieting.