TV & SAT TV
Community Installations
Use of antenna / cable systems for CCTV monitoring
The ways to adapt existing community antenna installation or cable network for video surveillance system.
The guidelines:
- Possibility of monitoring the surroundings of the building on TV sets,
- Use of existing antenna / cable network,
- Cooperation with standard televisions,
- Affordable price,
- Unchanged performance of the installation,
- Possibility of using every CCTV camera generating complete video signal (CVBS),
- Possibility of using color cameras with microphones.
The ways of distribution CCTV signals in community antenna installations or cable networks:
- adaptation of community installation based on channel amplifiers (fig. 1),
- adaptation of community installation based on broadband amplifier (fig. 2),
- adaptation of cable TV network - connection before building amplifier (fig. 3),
- adaptation of cable TV network - connection after building amplifier (fig. 4),
- utilization of low attenuation of RF loop US-501 modulators (fig. 5).
The components used: channel amplifiers ZG-401 or ZG-301 (R90515, R90517), power supply adapter for ZG amplifiers - AS-101 R90510, broadband amplifier PA-004 R91278, power supply adapter for PA and MS series - FA-202 R91226, frame MS-011 R91229, VSB modulator MS-501 R91229, power supply adapter for cameras ZS-12/400 M1810, DSB modulator MT-09 R87162.
Utilization of community installation built on the basis of channel amplifiers
Simple solution, consisting in adding next channel amplifiers. The original parameters of the installation do not change.
Adaptation of community installation based on broadband amplifier
Simple solution, with combining signals from RF modulators and the signals from the antennas, at the input of the amplifier. Its disadvantage is additional attenuation of antenna signals in the combiner. In the case when terrestrial TV does not use channels above 60, there may be used diplexer/multiplexer.
Adaptation of cable TV network - connection before building amplifier
Rather complicated implementation, with combining signals from RF modulators and the signals coming from the distribution network, at the input of the amplifier. Its disadvantage is attenuation of the input signals by the combiner. In the case when cable television does not use channels above 60, it is possible to employ a diplexer (lower attenuation). There may be problems with equalization of channel levels and nonlinear distortions.
Adaptation of cable TV network - connection after building amplifier
Complicated implementation, it consists in connecting channel amplifiers in series (via RF loops) with the output of building amplifier. There are no problems with channels leveling, and equalization of channel levels and nonlinear distortions, but it is rather controversial solution due to necessity of using filters between the building amplifier and the channel amplifiers. It should be used carefully, after a thorough analysis.
Modulators for home use:
MOD-2 (Inel):
- channels: 29 - 43,
- sound 5.5 or 6.5 MHz (switched),
- test signal,
- output level: 65 dBuV,
- SCART input,
- included AC/DC adapter (12V/100mA).
Modulators for professional applications:
MS-401 (Alcad):
- channels: 21 - 69,
- sound 6.5 MHz,
- output level 82 dBuV,
- RCA input,
- DSB,
- included AC/DC adapter.
MS-501 (Alcad):
- channels: 1 - 5, 6 - 12, 21 - 69, S1 - S18, S19 - S38,
- sound 5.5 MHz,
- output level 82 dBuV, adjustment -10 dBuV,
- mini-DIN input,
- VSB,
- requires power adapter (FA-202).
MT-09 (Terra):
- channels: 21 - 69,
- sound 5.5 or 6.5 MHz (switched),
- output level 85 dBuV, adjustment -15 dBuV,
- RCA input,
- requires AC/DC adapter (with 12V/200mA output).
Main features:
- Sound and channels in D/K standard,
- Microcontroller,
- Frequency synthesis,
- RF loop allowing cascade connection of several modulators and simple combining with existing signals,
- Non-volatile memory, adjustment of output level.
Basic parameters:
Model | MT09 | MT09P | MT10 | MT10P |
| Output level [dBuV] | 70 - 85 | |||
| Output channels | 21 - 69 | 21- 69 | 6 -S18 (OIRT)/ 5 - S20 (CCIR) | 6 - S18 (OIRT)/ 5 - S20 (CCIR) |
| Sound subcarrier [MHz] | 6.5 (D/K) / 5.5 (CCIR) | |||
| Audio input level [mV] | 150 - 775 | |||
| Frequency range / RF loop attenuation | 47- 862 MHz / 2 dB maks. | |||
| Power consumption | 11.5 - 13 V /200mA | 230V/50Hz/ 5VA | 11.5 - 13 V /200mA | 230V/50Hz/5VA |
Dimensions/ weight [mm] / [kg] | 54x120x100/ | 54x120x142/ | 54x120x100/ | 54x120x142/ |
Basic requirements for community antenna systems and cable networks.
The measurements of basic parameters of RF network can be done with a signal level meter, e.g. TC-402.
Frequency ranges used in community antenna installations:
Table 1. Frequency ranges used MATV systems and cable TV networks.
Range | Frequency band [MHz] | Band/channel symbols |
| FM band | 87.5 - 108.0 | FM |
| Lower special band | 110 - 174 | S01 - S08 |
| VHF III | 174 - 230 | K06 - K12 |
| Upper special band | 230 - 302 | S09 - S17 |
| Extended special band (hyper-band) | 302 - 470 | S18 - S38 |
| UHF IV | 470 - 606 | K21 - K37 |
| UHF V | 606 - 862 | K38 - K69 |
TV channel specification list can be found here
Main features of community / cable installations:
- As the sources of signals distributed in these installations can be terrestrial and satellite radio and TV broadcasts, as well as locally prepared/played audio-video materials,
- Distribution of RF signals to the subscribers' outlets should be performed according to the standards used in the country,
- There are allowed only the components/devices having appropriate certificates valid in the country,
- There should be used components/devices of 75 ohm impedance,
- The power of parasite radiation of any device cannot exceed 100 pW,
- The attenuation of outer radiation should guarantee that, in any output of the installation and at any frequency, the ratio of the carrier to the interfering signal caused by electromagnetic field of intensity equal 3V/m will be not less than 64 dB for television signals and 50 dB for FM signals.
- Recommended minimum signal level in subscriber's outlet Uabmin = 62 dBuV (depended on the band),
- Recommended maximum signal level in subscriber's outlet Uabmax = 80 dBuV (depended on the band),
- Minimum signal to noise ratio - S/Nmin = 44 dB (TV, AM mod., 5 MHz band), 15 dB (TV FM mod., 27 MHz band), 54 dB (FM-stereo, 0.25 MHz band), 44 dB (FM-mono, 0.15 MHz band),
- Minimal signal to intermodulation products ratio - S/Imin = 60 dB, enforcing reduction of the maximum output level in amplifier's output, accordingly to the table 2.
Table 2. Reduction of the maximum output level dependent on the number of active channels
Number of channels | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 12 | 16 | 20 | 24 | 28 | 36 |
| Reduction of level [dB] | 0 | 2 | 3.5 | 4.5 | 5 | 5.5 | 6 | 8 | 9.5 | 10.5 | 11.5 | 11.7 | 12.5 |
- All programs should have the same power level,
- The maximum difference in signal levels cannot exceed:
3dB (for neighbor channels),
6dB (in any band 60 MHz wide),
12dB (within the whole spectrum),
- Minimum separation between two receivers: 44dB,
- All parameters should be kept during 95% of the time,
- The gain of TV antennas within one channel or the FM antenna within FM band shouldn't change more than 0.5dB.
Modulators
There are two types of modulators that are used in television technique:
- Dual-side band: DSB - AM,
- With partially attenuated side band - VSB - AM (vestigial side band).
They differ in the spectrum, so the occupied band. VSB-AM modulation is used in terrestrial TV transmitters and higher-class modulators, e.g. used in the head stations of cable television. VSB modulators can work without channel spacing (e.g. in channels 50, 51, 52, 53, 54, 55 etc.), which allows to accommodate more programs.
DSB-AM modulation is used in simple modulators built in SAT receivers, VCRs, TV games, etc. Generally, due to a wider spectrum, DSB-AM modulators have to be set every second channel - with one channel space - (e.g. in channels 50, 52, 54, 56, 58, etc).
The spectra of DSB - AM and VSB - AM signals
We also recommend installation diagrams.
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