which transmits and receives Radio signals
agnetic waves. Antenna used for the transmission of Radio, TV,
, GSM and CDMA network.
y in all direction)
nal antenna of array of dipoles.
- Parabolic: - It is made up of 2 to 4 meter diameter
nd its components are Reflector, Feed, Support (Tie beam)
------------------------------ Or ------------
Λ
(Wavelength) 2
Antenna Gain as per the system and diameter:-
.8 M dia 28.9 dB
12.75 – 13.25 GHz 1.2 M dia 41.7 dB
Dia
t
7-3 Microwave constituents
7-3.1 1. Antenna: -
It is a metallic device
in the form of electrom
M/W
There are two types of antennas. 1. Omni directional (radiates equall
It is a simple rod.
2. Directional (radiates in one direction only)
- Yagi : - Directio
a
Antenna gain: -
= 4
П
A (equivalent area of antenna.) 4n (frequency) A (area)
----------------
2
- If size of antenna is reduced, gain is reduced.
- If frequency is increased, gain increased.
- Size of antenna depends upon operating frequency, Atmospheric losses and Rain losses.
2.0 – 2.3 GHz 0.6 M dia 19.6 dB
1.2 M dia 25.6 dB
1
1.8 M dia 45.1 dB
me er 2 G 6G 7 G 11 G
1.8 M 29 38.3 39.2 43.8 dB
43.0 45.0 48.1 dB
It is to be done to avoid moisture, dirt, and corrosive gasses. W/G are
etime high
o required for sealing against leaks. One of such dehydrator is from High
N,
-
Low power,
-
Overload ,
-
Alarm, and
- Pressure and Humidity indicators.
aximum operating Pressure: - 0.25 Kg / cm2
inimum -------‘’------------ -:- 0.10 Kg / cm2
ow pressure alarm : - 0.08 Kg / cm2
ressure should hold for 12 Hours.
2.4 M 31.5 40.2 41.2 46.2 dB
3.0 M 33.4
3.7 M 35.0 44.8 46.4 49.6 dB
2. Wave-guide Pressurization and dehydration:-
to be filled by gas and it is to be properly sealed. Pressure may go down for any leakage.
The machine to generate this slight pressure is called Dehydrator. Som
pressure is als
Tech Pneumatics Dehydrator. LEDs are provided on front panel such as,
-
Compressor O
M
M
L
P
185
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