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Senior Member
Reputation: 570
GSM 1800 having limited coverage area
Hi guys - Just want to asked what might be some factors for GSM sites (900/1800) to have limited/small coverage area. Is VSWR or transmission a factor for this. Of course, terrain type was already considered.
Thanks and BR,
freakturd06
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" The Best Things in Life are Free"
Password: fitched
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2011-01-26 10:46 AM
# ADS
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Member
Reputation: 172
Re: GSM 1800 having limited coverage area
Originally Posted by
freakturd06
Hi guys - Just want to asked what might be some factors for GSM sites (900/1800) to have limited/small coverage area. Is VSWR or transmission a factor for this. Of course, terrain type was already considered.
Because of BW size , coverage area differ from 900 to 1800....CDMA has much high coverage area than 900 and 1800 because of low BW. 900 coverage area is around 6dBm higher than 1800. Propagation loss is higher in 1800. So, operator always want to build site with lower bad and therfore LTE 900 is getting popular...
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Member
Reputation: 20
Re: GSM 1800 having limited coverage area
Hope below helps!!!
As the freq increases the pathloss also increases..
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Senior Member
Reputation: 502
Re: GSM 1800 having limited coverage area
Originally Posted by
freakturd06
Hi guys - Just want to asked what might be some factors for GSM sites (900/1800) to have limited/small coverage area. Is VSWR or transmission a factor for this. Of course, terrain type was already considered.
Due to path loss is 6 dB less+ 3dB MS TX power less+1 dB cable loss as compare with the 900 so total 10 dB difference .
Hope this help you
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Member
Reputation: 138
Re: GSM 1800 having limited coverage area
Hi,
radio coverage do not depend from transmission lines, very important for good radio coverage are: antenna tilt (mechanical and electrical), good VSWR, low losses of feeder lines. Very good VSWR, not always means good feeder line, some time this mean high losses.
If you have problem with coverage is good to check:
- BTS output power, is same that you expect
- Antenna tilt for each band (Mech.&El.)
- pass through band of lightning protection, if you have
- pass through band of splitters, combiners, tma
- VSWR & cable loss
Generality check antenna feeder system
BR
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Senior Member
Reputation: 570
Re: GSM 1800 having limited coverage area
Thanks and BR,
freakturd06
-------------------------------------
" The Best Things in Life are Free"
Password: fitched
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Member
Reputation: 182
Re: GSM 1800 having limited coverage area
Originally Posted by
RF engineer
Due to path loss is 6 dB less+ 3dB MS TX power less+1 dB cable loss as compare with the 900 so total 10 dB difference .
Hope this help you
Hi RF!, have you any tool or excel to calculate this?.
The pattloss difference we can calculate with ITU, Hata, Egli, etc., but the other two variables?.
Thanks!
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Re: GSM 1800 having limited coverage area
Gyus , you forgot one more thing - TDMA limits GSM coverage also
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Senior Member
Reputation: 502
Re: GSM 1800 having limited coverage area
Originally Posted by
prodigy
Hi RF!, have you any tool or excel to calculate this?.
The pattloss difference we can calculate with ITU, Hata, Egli, etc., but the other two variables?.
Thanks!
Dear
Really i don't but this are general guidelines .
BR
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Junior Member
Reputation: 10
Re: GSM 1800 having limited coverage area
check first for the RxLev near the site (it must be very strong around -50 to -60dBm). Compare also your results to other site so that you have a basis.
If youre site now has low RxLev as compare to site w/ good coverage, then it must probably be VSWR.
If not, check for the tilting (MT and ET).. also check the TxPower!
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