USE OF THE HF BROADCASTING BANDS A SHORT OVERVIEW EBU TECHNICAL DEPARTMENT HISTORY CONGESTION HFBC...
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Transcript of USE OF THE HF BROADCASTING BANDS A SHORT OVERVIEW EBU TECHNICAL DEPARTMENT HISTORY CONGESTION HFBC...
USE OF THE HF BROADCASTING BANDS
A SHORT OVERVIEW EBU TECHNICAL DEPARTMENT
• HISTORY
• CONGESTION
• HFBC PLANNING PARAMETERS
• THE THREAT OF PLT
• DIGITAL FUTURE
TERRY O’LEARY
For associated text, see attached
notes
HISTORY (1)
BEFORE 1979 : 2350 kHz
BELOW 10 MHz : 725 kHz
WARC–79 : + 780 kHz ( after 1996 )
BELOW 10 MHz : + 125 kHz
WARC–92 : + 790 kHz ( after 2007 )
BELOW 10 MHz : + 200 kHz
* excluding tropical bands :
2300-2498 MHz 3200-3400 MHz 3950-4000 MHz4750-4995 MHz 5005-5060 MHz
HISTORY (2)BAND
6 MHz
7 MHz
9 MHz
11 MHz
13 MHz
15 MHz
17 MHz
19 MHz
21 MHz
26 MHz
PRE – 79
5950 – 6200
7100 – 7300
9500 – 9775
11700 – 11975
–
15100 – 15450
17700 – 17900
–
21450 – 21750
25600 – 26100
WARC–79
5950 – 6200
7100 – 7300
9500 – 9900
11650 – 12050
13600 – 13800
15100 – 15600
17550 – 17900
–
21450 – 21850
25670 – 26100
WARC–92
5900 – 6200
7100 – 7350
9400 – 9900
11600 – 12100
13570 – 13870
15100 – 15800
17480 – 17900
18900 – 19020
21450 – 21850
25670 – 26100
+125
+125
+200
+150
+150
+100
-70
+50
+50
+100
+100
+100
+200
+70
+120
HISTORY (2´)BAND
6 MHz
7 MHz
9 MHz
11 MHz
13 MHz
15 MHz
17 MHz
19 MHz
21 MHz
26 MHz
PRE – 79
5950 – 6200
7100 – 7300
9500 – 9775
11700 – 11975
–
15100 – 15450
17700 – 17900
–
21450 – 21750
25600 – 26100
WARC–79
5950 – 6200
7100 – 7300
9500 – 9900
11650 – 12050
13600 – 13800
15100 – 15600
17550 – 17900
–
21450 – 21850
25670 – 26100
WARC–92
5900 – 6200
7100 – 7350
9400 – 9900
11600 – 12100
13570 – 13870
15100 – 15800
17480 – 17900
18900 – 19020
21450 – 21850
25670 – 26100
BELOW 10 MHz : + 125 + 200
ABOVE 10 MHz : + 655 + 590
CONGESTION(1)
BELOW 10 MHz
DAYTIME : SHORT TO MEDIUM DISTANCE ( 2000 km )
NIGHTTIME : LONGER DISTANCES
LOCAL WINTER : FOR SHORT DISTANCES 6MHz BETTER ( THERE ARE NO BANDS AT PRESENT )
RELIABILITY : RECENT TENDENCY TO USE SHORT DISTANCE, SINGLE HOP MORE CONGESTION
CONGESTION : SOME USE OF WARC-92 BANDS ALLOWED ( RR 4.4 ); THESE BANDS NOW ALSO CONGESTED
COORDINATION : IMPROVED SITUATION ( ARTICLE S12 )NEVERTHELESS CONGESTION
MINIMUM HF TRANSMISSION DISTANCES
CONDITIONS : December
SSN = 20 Reliability = 90%
6, 7 MHz could be used for shorter distances:• poorer quality
• reduced reliability• increase congestion
• create additional interference
UTC 3 4 5 6 7 17 18 19 20 21 22 23
FREQ km km km km km km km km km km km km
6MHz
1700 1800 2000 1500 600 … 1250 1450 1500 1550 1400 1300 1250
5MHz
1100 1200 1300 1000 300 … 750 950 1000 1000 950 850 800
4MHz
750 800 900 750 <250 … 500 650 650 650 600 500 500
3.3 MHz
450 550 600 450 <250 … <250 300 300 300 250 <250 <250
CONGESTION(2)
STATISTICS (1)HFCC USAGE* : WINTER SEASON 2000
* WORLD WIDE EXCEPT CENTRAL AND SOUTH AMERICA AND MOST SOUTHERN AFRICAN COUNTRIES
BAND FREQ CHANSTROP.
Tx-hrs/dayWARC-77 Tx-hrs/day
WARC-92
Tx-hrs/day
OOB Tx-hrs/day
TOT Tx-hrs/day
4
3900-3950 5 14
1013950-4000 5 53
4000-4050 5 34
6
5700-5900 20 210
33285900-5950 5 345
5950-6200 25 2747
6200-6300 10 26
7
6850-6990 14 10
30657100-7300 20 2104
7300-7350 5 289
7350-7600 25 662
9
9250-9400 15 209
38579400-9500 10 448
9500-9900 40 2970
9900-9990 9 230
TOT 213 53 7821 1082 1395 10351
+13.8%
+17.8%
110 hrs/ch
105 hrs/ch
74 hrs/ch
STATISTICS (2)HFCC USAGE* : WINTER SEASON 2000
* WORLD WIDE EXCEPT CENTRAL AND SOUTH AMERICA AND MOST SOUTHERN AFRICAN COUNTRIES
BAND FREQ CHANSTROP.
Tx-hrs/dayWARC-77 Tx-hrs/day
WARC-92
Tx-hrs/day
OOB Tx-hrs/day
TOT Tx-hrs/day
4
3900-3950 5 14
1013950-4000 5 53
4000-4050 5 34
6
5700-5900 20 210
33285900-5950 5 345
5950-6200 25 2747
6200-6300 10 26
7
6850-6990 14 10
30657100-7300 20 2104
7300-7350 5 289
7350-7600 25 662
9
9250-9400 15 209
38579400-9500 10 448
9500-9900 40 2970
9900-9990 9 230
TOT 213 53 7821 1082 1395 10351
(236/2747)25 = 2…
(672/2104)20 = 6 …
(439/2970)40 = ~6
HFBC PLANNING PARAMETERS
• N (noise) : < ~10 dB(V/m) for HF between 1 - 10 MHz
• RF S/N ratio : 34 dB
• PR : 17 dB (fair) to 27 dB (good)
10
dBV/m
noisef
FS
S/N = 34
Wanted signal
THE THREAT OF PLT
Noise levels
proposed max.levels
~43
34dB
DIGITAL FUTURE (1)
WRC-97 : HF DSB to cease by 31 Dec. 2015
- replace by SSB or other spectrum efficient systems (i.e., digital) (Res. 537)
- replacement interference not to exceed DSB
- Spectrum efficient techniques to be recommended by ITU-R
- final date for cessation of DSB to be reviewed by future WRCs
DIGITAL FUTURE (2)
Principles of the DRM Standard:
- Single, universal (low cost) receiver
- Applicable to HF, MF, LF (i.e. same receiver)
- Compatibility with existing situation (analogue, channel spacing, frequency bands, …)
DIGITAL FUTURE (3)European HF broadcasters intend:
1. to use the HF bands for the foreseeable future
2. introduce DRM within the next 5 to 10 years
3. increase the # of programmes and services
UNLESS …
the spectrum below 30 MHz is turned into
a PLT PARADISE
a BROADCASTING WASTELAND
…