background image

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

L A B E L   I T A L Y     S R L

  -   V i a   S .   A l l e n d e ,   5 9   –   4 1 1 2 2   M O D E N A

 

T E L :   0 5 9 / 3 6 2 9 9 3         F A X :   0 5 9 / 3 7 6 0 5 6

 

P . I V A   0 2 5 7 8 7 5 0 3 6 2           C a p i t a l e   S o c i a l e   3 2 . 5 0 0   E u r o      

w e b   - w w w . l a b e l i t a l y . c o m         e - m a i l   -   i n f o @ l a b e l i t a l y . c o m  

 
 
 
 

GENERAL RULES

 

 
 

 

 

 

  FM BROADBAND ANTENNAS 

( Dipole, Yagi, Panel, Circular), 

  VHF-UHF-SHF  ANTENNAS  

( Corner, Yagi, Parabols from 200 Mhz to 2,5 Ghz), 

  FM STAR TYPE COMBINERS 

  FM DOUBLE BRIDGE  COMBINERS 

  COAXIAL CAVITIES AND NOTCH 

  POWER  SPLITTERS 

  HYBRID COUPLERS 

  DIRECTIONAL COUPLERS 

  CABLES, CONNECTORS  AND  ADAPTERS 

  INSTALLATION ACCESSORIES 

 

 
 
 
 
 

Summary of Contents for Circular

Page 1: ...u r o web www labelitaly com e mail info labelitaly com GENERAL RULES FM BROADBAND ANTENNAS Dipole Yagi Panel Circular VHF UHF SHF ANTENNAS Corner Yagi Parabols from 200 Mhz to 2 5 Ghz FM STAR TYPE COMBINERS FM DOUBLE BRIDGE COMBINERS COAXIAL CAVITIES AND NOTCH POWER SPLITTERS HYBRID COUPLERS DIRECTIONAL COUPLERS CABLES CONNECTORS AND ADAPTERS INSTALLATION ACCESSORIES ...

Page 2: ...s of time while the antenna system is energized All the maintenance or repairs should be done with the transmitter switched off If the antenna is not pressurized condensation can occur inside the antenna harness resulting in possible failure of the antenna LIGHTNINGS ORIGINS AND PROTECTION CRITERIA The violent and timely atmospheric perturbations in which electrical phenomena are involved such a l...

Page 3: ... dispersor can be either vertical pickets or horizontal rings or nets depending on the resistivity of the terrain Finally it will be necessary to link the metallic fence to the general grounding system while the distance between such fence and the dispersors of the system shall not exceed 5 meters One should remember that in order to have a more efficient shielding the screens of the cables and th...

Page 4: ...ependent upon the direction of rotation as seen from the transmitter Another form of polarisation is known as elliptical polarisation It occurs when there is a mix of linear and circular polarisation However it is possible for linearly polarised antennas to receive circularly polarised signals and vice versa The strength will be equal whether the linearly polarised antenna is mounted vertically ho...

Page 5: ... terms of its radiated power however the antenna performs in an exactly equivalent manner for reception having identical figures and specifications In order to visualize the way in which an antenna radiates a diagram known as a polar diagram is used This is normally a two dimensional plot around an antenna showing the intensity of the radiation at each point for a particular plane Normally the sca...

Page 6: ...an isotropic source is sometimes used In this case the gain may be specified in dBi i e gain in decibels over an isotropic source The main drawback with using an isotropic source antenna dBi as a reference is that it is not possible to realize them in practice and so that figures using it can only be theoretical However it is possible to relate the two gains as a dipole has a gain of 2 1 dB over a...

Page 7: ...the back lobe tilt up In almost all practical cases antennas are only tilted down Occasionally the mechanical and electrical tilt will be used together for odd situations in order to create greater beam tilt in one direction than the other mainly to accommodate unusual terrain Along with null fill beam tilt is the essential parameter controlling the focus of radio communications and together they ...

Page 8: ...or using RF equipment it can sometimes be useful to convert between return loss VSWR and voltage reflection coefficient Return Loss dB is defined as a ratio of the incoming signal to the same reflected signal as it enters a component The Return Loss RL may also be explained as the difference between the power of a transmitted signal and the power of the signal reflections caused by variations in l...

Page 9: ... often do not know the actual mismatch The forward power measurement is required to calculate the VSWR or Return Loss number This can be necessary because some transmitters have an output stage protection circuit which reduces power under highly VSWR conditions Network Analyzer Spectrum Analyzer with Tracking Generator These devices do not rely upon the site s transmitter as a signal source They c...

Page 10: ...re Periodic inspection of these openings is the responsibility of the owner They must remain clear of debris to preclude corrosion from internal condensation Such damage can drastically affect performance and is not covered by warranty Is the antenna intermittent It is a good idea to shake the antenna during the above tests to ensure there are no mechanical intermittents Poor connections may lead ...

Reviews: