Multistation Antennas

DCR-M The DCR-M Series FM antenna has been used extensively for high power
broadband applications. The M series antennas are circularly polarized with a
power rating of 18 kW for a single bay and available in stacked arrays of up to
16 bays with an input rating to 40 kilowatts. For situations where ice formation
is common, the arrays can be equipped with optional electrical deicers.
Antenna is DC grounded and does not require shorting stubs. Each DCR-M
array is supplied with fine matcher for field optimization.
For reduced downward radiation, the use of a custom feed design allows for
shorter spacings in a series fed configuration.
High Power Input Capability
The DCR-M antenna is available with optional 4-1/16" feed system having a
power input rating (for five or more bays) of 70 kW. Arrays with 6-1/8" inputs
are also available.
Multi-Station Operation
The wide bandwidth and high power input capability of the DCR-M antenna
permit optional multi-station operation. Dual station antennas having a
frequency separation of less than 3.0 MHz can employ an end fed system.
Beam Tilt and Null Fill
Beam tilt and/or null fill are available as options on the DCR-M series. These
options are ordinarily specified for arrays of eight bays or more. Even num-
bered arrays of six sections and fewer may include one or both options and
• Stainless steel construction typically are designed as a center fed array. The DCR-M antenna is available
• 18 kW for a single bay in arrays which are custom-built to the needs of the station. Refer to DCR-C
for directional arrays.
• Wideband-suitable for multi-
station operation (optional) Directional Arrays
• Circularly polarized The DCR-M antenna is available in directional arrays which are custom-built
• Fine matcher included to the needs of the station. Refer to pattern studies on page 23 for addition-
al information.
• Integral deicers (optional)
• Arrays to 16 bays Electrical Specifications
• Low ice sensitivity
• VSWR field adjustable Antenna Gain Polarization1 Power
Type λ spacing 1/2 λ spacing Rating
General Specifications Power Gain dB Power Gain dB kW3

Polarization: Circular DCR-M1 0.46 -3.37 0.46 -3.37 18

DCR-M2 1.00 0.00 0.70 -1.55 36
Pattern Circularity in
DCR-M3 1.50 1.76 1.00 0 40
Free Space: ± 1 dB
DCR-M4 2.10 3.22 1.30 1.14 40
VSWR (max.) at Input, DCR-M5 2.70 4.31 1.50 1.76 40
w/o field trim: DCR-M6 3.20 5.05 1.80 2.55 40
Top Mounted 1.2:1 DCR-M7 3.80 5.80 2.10 3.22 40
Side Mounted 1.5:1 DCR-M8 4.30 6.34 2.30 3.62 40
VSWR (max.) at Input, w/field trim, DCR-M10 5.50 7.40 2.90 4.62 40
Top or Side Mounted DCR-M12 6.60 8.20 3.50 5.44 40
(+/-200 KHz): 1.05:1 NOTES:
(+/-400 KHz): 1.10:1 1. RMS gain data is given relative to dipole. Values are for each polarization and nominal for
midband and include standard harness configurations. Actual gain will vary depending on feed
Input: 3-1/8" EIA
system, frequency, null fill and bean tilt.
Section Dimensions: 2. Average power ratings are nominal @ 40°C ambient. Assumes constant pressurization with dry
Diameter 36" (915mm) air or nitrogen. Ratings may vary based on specific feed system design and local conditions.
3. Higher power ratings and custom feed systems may be available on request.
Height 29" (737mm)
4. Antenna components and feed harnesses are optimized for FM channels of interest.

14
Multistation Antennas

Mounting Dimensions

Ha = Antenna aperture length

Hc = Antenna center of radiation
Ho = Minimum overall length
needed for mounting

Ha= 984 x [s(x-1)]

f
Hc= Ha
2
Hoendfed= Ha+5'top+10' 5"bottom

Hocenterfed= Ha+5'top+ 5'bottom

All dimensions in feet

f = frequency in megahertz (MHz)
s = bay spacing in fraction of
wavelengths,
example: 1/2 wavelength = .5
x = number of bays
*This dimension may be extended
based on engineering review of
antenna mounting requirements
**Antennas ordered with beam tilt
and/or null fill are supplied with
center feed and require an even
number of bays

Deicer Specifications: Optional:

Power (nominal, per bay): 1200 W Ice sensor and deicer controller.
Voltage: May be wired for 208V or 240V service, single phase.

Mechanical Specifications

Antenna Without Deicers With Deicers

Type # of Weight Windload Projected Weight Windload Projected
bays lbs (kg) lbs (kg) Area ft2 (m2) lbs (kg) lbs (kg) Area ft2 (m2)
DCR-M1 1 88 (40) 164 (74) 3.3 (0.3) 93 (42) 170 (77) 3.4 (0.3)
DCR-M2 2 236 (107) 327 (149) 6.5 (0.6) 246 (112) 335 (152) 6.7 (0.6)
DCR-M3 3 324 (147) 491 (223) 9.8 (0.9) 339 (154) 510 (232) 10.2 (0.9)
DCR-M4 4 412 (187) 654 (298) 13.1 (1.2) 432 (197) 685 (312) 13.7 (1.3)
DCR-M5 5 500 (228) 817 (372) 16.4 (1.5) 525 (239) 860 (391) 17.2 (1.6)
DCR-M6 6 588 (268) 981 (446) 19.6 (1.8) 618 (281) 1,030 (469) 20.6 (1.9)
DCR-M7 7 676 (308) 1,144 (521) 22.9 (2.1) 711 (324) 1,205 (548) 24.1 (2.2)
DCR-M8 8 764 (348) 1.308 (595) 26.2 (2.4) 804 (366) 1,380 (628) 27.6 (2.6)
DCR-M10 10 940 (428) 1,635 (744) 32.7 (3.0) 990 (450) 1,675 (762) 33.5 (3.1)
DCR-M12 12 1,116 (508) 1,962 (893) 39.2 (3.6) 1,176 (535) 2,070 (942) 41.4 (3.8)
NOTES:
1. Weights include bays and standard extension brackets for mounting. Excludes feed system and custom mounts. For antennas that included
pattern studies, contact factory for additional information.
2. Projected area includes bays and standard extension brackets. Excludes feed system and custom mounts.
3. Dimensions are for antennas at 98.0 MHz and can vary ±10% across the band.
4. Ice shields are strongly recommended for areas subject to tower icing. Dielectric is not responsible for antenna damage caused by impact
from falling ice.
5. Area calculated expressed in terms of equivalent flats (RS-222-C-standard).
6. Windload force calculated based on 50 pounds per square foot (50psf) on flats (RS-222-C-standard).
7. To convert area to equivalent rounds, multiply area by 1.5.
8. To convert area to Aerodynamic area (CaAa - linear or CaAc - discrete) based on EIA-222-F standard, multiply area by 1.8.

15