R & L Media Systems

Rabbit Ears

 
 
 

 

Exploring Rabbit Ears Coverage

  For years there has been a great mystery as to what field strength contour is needed to get good rabbit ears coverage. The FCC says 48 dBu for full power stations, but that seemed too low. So one Saturday I set out to find what this mystical number was.

  Step 1 was to calculate what the field strength was for various stations in the area at my house, then convert those numbers to dBuV, the standard for field strength meters.

  Step 2 was to take a Promax TV Explorer and a $10.00 RCA ANT 112F rabbit ears and put it outside on a post. I measured the signal strength for each channel to get an idea how good the antenna was compared to what the Longley Rice program said the "STANDARD" should be.

  Step 3, I took my "rig" to various rooms of the house. I placed the antenna on top of the TV for that room in a way that looked appealing, a realistic approach. The final step was to compare all of this information to get an average value needed to get Rabbit Ears coverage in my house.


 

 

Ch.
Freq.
dBu
dBuV

5
76
87
81.34

7
174
62
49.15

8 *
180
74
60.85

10
192
76
62.29
Step 1
15
476
90
68.41

21
512
95
72.77

23
524
84
61.57

25
536
96
73.38

33
584
96
72.63

36
602
95
71.37
 


 
Outside
MER
dBuV
Diff.

26.2
72.5
-8.84

25.3
47.9
-1.25

16.4
46.7
-14.15

27.8
59
-3.29
Step 2
29.5
72
+3.59

29.4
77.4
+4.63

26.7
64
+2.43

30.3
74.2
0.82

27.8
62.0
-10.63

29.7
64.9
-6.47
 


 
Den
dBuV
Diff.
Office
dBuV
Diff.
Upstair BR
dBuV
Diff>

63.0
-18.34

61.8
-19.54

63.5
-17.84

41.0
-8.15

41.9
-7.25

44.1
-5.05

49.2
-11.65




39.0
-21.85

58.3
-3.99

50.4
-11.89

51.9
-10.39
Step 3
60.0
-8.41

65.5
-2.91

70.2
+1.79

63.4
-9.37

70.7
-2.07

76.0
+3.23

47.2
-14.37

48.7
-12.87

51.0
-10.57

42.0
-31.88

57.2
-16.18

66.6
-6.78

51.1
-21.53

56.4
-31.88

57.8
-14.83

56.8
-14.57

64.3
-16.23

57.9
-13.47
 


 
House Average -9.7
-5.6
-2.6
-5.5
-6.7
-7.4
-15.0
-19.1
-11.9
-8.3
 

Average house loss: 9.2 db
It appears to require 45 dBuV to get a solid locked signal.
This comes to a signal strength outside of 54.2 dBuV. (45 dBuV + 9.2 db)
(Log(Freq)*20)-31.96+dBuV = dBu, THUS
Ch.2-6 = 59 dBu Ch.7-13 = 68 dBu Ch.14-50 = 77 dBu


135 North Country Club Dr * Hendersonville, TN 37075 * sales@rlmediasystems.com