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Mobile Communication System (MCS) Job Aid 2

EETP/BSNL Platinum Certification Course Version 1.0 June 2014 Page 1of 4

For Restricted Circulation

2 JOB AID- 02 (W1/P2)

Name of participant: ...

Registration Number: .

2.1Title: BTS Testing - Feeder Cable & VSWR.

2.2Objective: On completion of this exercise, the participant will be able to:

a) Identify various types of feeder cable.

b) Explain the importance of VSWR

c) Explain how to measure the VSWR

d) Effects of VSWR.

2.3 Venue/ Site:

2.4 Setup/Equipments Required:

Participant has to visit the Mobile antenna system location or a Lab in Training

Centre. Piece of feeder cable and jumper cable.

2.5Reports to be taken/ referred:

Note down the value of VSWR for different cables.

2.6Exercise:

2.6.1 Visit the BTS site; try to identify the type of Feeder Cable and Jumper Cable

used there.

Type Frequency Band

Feeder Cable .. .

Jumper Cable . ..

2.6.2

Identify the difference between Jumper cable and Main feeder cable. Note

down the type (co-axial solid/rectangular/co-axial hollow circular) their

diameters in inches.


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Type Diameter

Jumper Cable .. ..

Main feeder cable .. ..

2.6.3

Write down the minimum and maximum value of VSWR..

Min VSWR __________________

Max VSWR _________________

2.6.4 Use the Calcucell software to calculate the VSWR for five different forward

and reflected powers.

Sl No. Forwarded Power Reflected Power VSWR


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2.6.5 For GSM 900 according to Okumara Hata model path loss is given as

L = 69.55 + 26.16logf - 13.82loghb - ahm + [44.96.55loghb]logd- Lc.

Factor Range

L path loss (dB)F frequency (MHz) 150-2000 MHz

hb base antenna height (m) 30-200 m antennas

above roof level (Take 30

Meter)

hm mobile antenna height (m) 1-10 m (Take 2Meter)

a (hm) = (1.1log(f)-0.7)hm-

(1.56log(f)-0.8) mobile antenna

height correction

D distance BTS-MS (km) 1-20 km

Lc correction factor for various

land usage/clutter categories

added to the Hata formula

Take 8 for sub urban area

Calculate the distance for path loss 130 db at 900 MHz antenna height hb=30 mt.

Now repeat the calculation assuming that VSWR has restricted the allowed path loss

to125 db and compare your result the first result and see the effect of VSWR on

coverage.

2.7 Learning Outcome:( to be filled by participants)

SELF ASSEMENT QUESTIONS

1. List the cause of High VSWR in RF Cable:

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

2.

List the effects of VSWR on Mobile Radio Network?

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________

_______________________________________________________________


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3. List view differences between feeder and jumper cable.

_____________________ __________________________

_____________________ __________________________

_____________________ __________________________

_____________________ __________________________

4. Value VSWR is dimensionless (True/ False)

5. With increase in VSWR the coverage area increase (True/ False)

6. List three models for calculation of path loss in mobile network.

7. Ideally the value of VSWR is less than 1(True/ False)

8. VSWR is property of a transmitter and not of the medium (True/ False)

9. Feeder cable is more flexible than Jumper cable. (True/ False)

10.

Calculate the length of dipole for 1900 Mhz frequency and compere with 900MHz.

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