Shively Labs FM Antennas and Accessories
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Typical Data for
Model 6813 FM Antenna (full-wave-spaced)

True Circular Polarization

Power Rating: 3 kW per Bay

Shively Standard Features:

  • Ring Stub Design
  • Consistently Predictable Patterns
  • Low Weight and Windload
  • Digital Ready
  • Pattern Studies Available
  • No Factory Personnel Needed to Install
  • Adjustable Fine-Matching Transformer
  • Radomes and Deicers Available
  • Rugged Corrosion-Resistant Mounts
  • Works with Regular Towers; No Need for Special Frequency-Sensitive Tower Sections
  • Pressure Relief Valve for Easy Purging of the System
  • Special Spacing, H/V Ratios, Null Fill and Beam Tilt Available

Performance Specifications:

Polarization:
Right circular.
VSWR:
1.08 : 1 ± 100 kHz.
1.16 : 1 ± 200 kHz (optional 1.10 : 1; see factory for details)
Azimuth Pattern Circularity:
Horizontal component ±1.5 dB on pole.
Input Connection:
1-5/8 in EIA Female.

Electrical Specifications (full-wave-spaced):
No. of
Bays		 Gain
 Power
Rating
kW		 No. of
Bays		 Gain
 Power
Rating
kW
Power dB Power dB
1
0.46
-3.40
3
7
3.87
5.88
12
2
0.99
-0.04
6
8
4.46
6.50
15
3
1.55
1.90
9
10
5.65
7.52
15
4
2.12
3.26
10
12
6.85
8.36
15
5
2.70
4.31
12
14
8.05
9.06
15
6
3.28
5.16
12
16
9.25
9.66
15

Notes:

Our gain figures are derived from the computed directivity and include the losses in the antenna feed system.

Gain is provided for one polarization and is equal in circularly polarized antennas for both horizontal and vertical components. Gain will be reduced if null fill, beam tilt, special H/V ratio, or special wavelength spacing is provided. Gain will increase in a directional array by the directivity of the azimuth pattern.

Size and Weight (full-wave-spaced):
No. of Bays Vertical Tower Space
 Weight
Antenna radiation aperture
 Physical
space used
 Total tower space recommended
 without
radomes
 with
radomes
 with radomes &
1/2"radial ice
ft m ft m ft m lb N lb N lb N
1
2
0.7
9
3.0
20
6.6
62
277
97
433
195
870
2
10
3.3
19
6.2
30
9.8
105
468
175
781
380
1695
3
20
6.6
29
9.5
40
13.1
147
656
252
1124
565
2520
4
30
9.8
39
12.8
50
16.4
190
847
330
1472
749
3341
5
40
13.1
49
16.1
60
19.7
259
1155
407
1815
934
4166
6
50
16.4
59
19.4
70
23.0
275
1227
485
2163
1119
4991
7
60
19.7
69
22.6
80
26.2
317
1414
562
2507
1303
5811
8
70
23.0
73
23.9
90
29.5
338
1507
618
2756
1444
6440
10
90
29.5
93
30.5
110
36.1
423
1887
773
3448
1814
8090
12
110
36.1
113
37.1
130
42.6
508
2266
928
4139
2183
9736
14
130
42.6
133
43.6
150
49.2
593
2645
1083
4830
2552
11382
16
150
49.2
153
50.2
170
55.8
676
3015
1239
5526
2922
13032

Windload (full-wave-spaced):
No. of
Bays		 Revision "C"
 Revision "F"
without radomes
 with radomes
 with radomes & 1/2" radial ice
 without radomes
 with radomes
 with radomes & 1/2" radial ice
lb N lb N lb N ft² m² ft² m² ft² m²
1
76
339
180
803
222
990
2.4
0.2
4.9
0.5
6.0
0.6
2
152
678
360
1606
442
1971
5.1
0.5
10.1
0.9
12.5
1.2
3
228
1017
540
2408
662
2953
7.7
0.7
15.3
1.4
18.9
1.8
4
304
1356
719
3207
881
3929
10.4
1.0
20.4
1.9
25.4
2.4
5
380
1695
899
4010
1101
4910
13.1
1.2
25.6
2.4
31.9
3.0
6
456
2034
1079
4812
1321
5892
15.8
1.5
30.8
2.9
38.4
3.6
7
532
2373
1258
5611
1540
6868
18.4
1.7
36.0
3.3
44.9
4.2
8
581
2591
1411
6293
1713
7640
20.2
1.9
40.2
3.7
49.9
4.6
10
732
3265
1771
7899
2153
9602
25.5
2.4
50.5
4.7
62.8
5.8
12
884
3943
2130
9500
2593
11565
30.9
2.9
60.9
5.7
75.8
7.0
14
1036
4621
2490
11105
3032
13523
36.2
3.4
71.2
6.6
88.8
8.2
16
1188
5298
2849
12707
3472
15485
41.5
3.9
81.6
7.6
101.7
9.4

Notes:

  1. The mounting structure must not flex more than ± 1/2 in (1.2 cm) in any ten-foot (3-meter) section. Five feet (1.5 m) of mounting structure is required above and below the antenna bays for proper pattern formation.
  2. Antenna radiation aperture is the distance from the center of the top bay to the center of the bottom bay. Physical space used is from the top of the top bay to the input flange at the bottom of the array, or the bottom of the bottom bay in a center-fed array. Total tower space recommended allows ten feet (3 m) of clear tower space above and below the antenna to protect from pattern interference by other antennas. At frequencies lower than 98 MHz, each of these dimensions will increase by up to 1 ft (0.3 m) per bay.
  3. Seven bays or less are normally end-fed. All antennas supplied with beam tilt will be center-fed. Antennas with an odd number of bays are normally not available with center feed.
  4. Windload and weight tabulations are estimates and assume 98 MHz. They include the bay, interbay feedline, input connection, and a fine-matching transformer. No values have been included in these tabulations for mounts. Actual values vary with the specific installation. Contact us with details of your installation if more precise values are needed.
  5. Antenna windloads are calculated for 112 mph (180 kph), using 50 psf (2400 N/m²) for flats and 33 psf (1600 N/m²) for rounds] per EIA standard RS-222-C and CSA standard S37-94. The surface area is calculated per EIA standard RS-222-F (CaAc).
  6. Deicers add approximately 1 lb (4.4 N) per bay in weight and 2 lb (8.9 N) or 0.05 ft² (0.005 m²) per bay in windload.
  7. Ask for technical assistance at Shively if you are planning to mount antennas on AM towers or install them at altitudes over 3,000 ft (915 m) above mean sea level.
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Last updated: 11/30/2007
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