Hello all,
just retreived some technical data from german LF-BC-station
in Donebach broadcasting the program of Deutschlandfunk
(alias Deutschlandradio Koeln). Perhaps the values listed here
are beneficial for field strength measurements.
======Donebach Profile Start========================
allocated frequency 153.0 kHz (+/- 4.5 kHz for audio sidebands)
attenuation at sideband boundaries -60dBc
attenuation beyond sideband boundaries better -80dBc
coordinates of the center of antenna system:
49N34 09E11 (degrees/minutes)
continuous operation 24 hours, 7days
daytime transmitter power = 500 kW
nightime transmitter power = 250 kW
at the moment (daytime saving time in effect = CEST)
daytime operation is from 03:00 UTC to 18:00 UTC
nightime operation is from 18:00 UTC to 03:00 UTC
during normal time (CET)
daytime operation is from 04:00 UTC to 19:00 UTC
nightime operation is from 19:00 UTC to 04:00 UTC
Antenna system comprises two masts of equal mechanical design.
total mast height 363 meters from ground level
masts are of the lattice type, 2m by 2m in cross section,
base is not isolated but directly grounded to a burried radial
system consisting of 60 radials 360m each.
The masts are guyed at 6 levels:
level-1 = 63m and level-2 = 120m
3 guy wires separated 120 degrees, isolators (7m) directly at the mast
level-3 = 180m and level-4 = 242m
3 guy wires separated 120 degrees, aligned in azimuth with guys
of level-1 and -2. guy wires are bonded to the mast inclining
53 deg and 45 deg respectively and have isolators (7m) after
150 m. So these guys act as capacitive loading.
level-5 = 308m
3 guy wires separated 120 degrees, aligned in azimuth 60 deg off
the guys of lower levels. The guys are directly bonded to the mast
incline exactly 45 degs down for a length of 250m where 7m isolators
breaking the remaining run to ground electrically. About 150m from
the mast feed wires are attached (one for each guy wire) which slope
down to the mast base where all are bonded together to form the feed point
of the antenna. This level acts as part of a folded monopole
as well as capacitive loading.
level-6 = 343m
3 guy wires separated 120 degrees, aligned in azimuth with guys of
level-5. The guys are directly bonded to the mast, incline exactly
45 degs down for a length of 165m where 10m isolators breaking the
remaining run to ground electrically. So these guys act as capacitive
top loading.
These two masts are separated by about 600m on a line beaming
111/291 degrees. Each mast feed has its own matching unit receiving
transmitter power from a power divider and phasing network located
at the antenna system's center.
During daytime operation, 500kW are fed to the mast on the western side,
the eastern side mast remains grounded at it's feed, acting as a passive
reflector.
During nighttime operation, 250kW are fed, asymmetrically divided,
to both masts. The antenna system acts like a phased array.
Following a simplified representation of actually measured
(on ground and by helicopter) Radiation patterns:
-----------------------------------------------------
Daytime Operation Azimuth Radiation pattern for TOA=zero!
nominal 500kW transmitter power
EMRP Azimuth Sectors (east of north)
29dBkW 310-20 degs
28dBkW 20-35 degs 190-310 degs
27dBkW 35-42 degs 175-190 degs
26dBkW 42-50 degs 160-175 degs
25dBkW 50-60 degs 145-160 degs
24dBkW 60-145 degs
-----------------------------------------------------
-----------------------------------------------------
Nighttime Operation Azimuth Radiation pattern for TOA=zero!
nominal 250kW transmitter power
EMRP Azimuth Sectors (east of north)
26dBkW 335-5 degs 200-227 degs
25dBkW 5-25 degs 190-200 degs 227-335 degs
24dBkW 25-45 degs 180-190 degs
23dBkW 45-55 degs 172-180 degs
22dBkW 55-62 degs 165-172 degs
21dBkW 62-67 degs 157-165 degs
20dBkW 67-73 degs 150-157 degs
19dBkW 73-76 degs 145-150 degs
18dBkW 76-80 degs 140-145 degs
17dBkW 80-85 degs 135-140 degs
16dBkW 85-90 degs 130-135 degs
14dBkW 90-130 degs
-----------------------------------------------------
======Donebach Profile End ==========================
73 de Gamal
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