- This topic has 113 replies, 1 voice, and was last updated 1 year, 1 month ago by Akbar Ali.
5th April 2007 at 07:22 #38388TechieGuest
why we use in some cases vertical polarization & horizontal polarization6th April 2007 at 04:43 #38389Imran SabirGuest
Can any body tell me,what is the effect oh HI-LO Voilation on the network while designing a Ring Topology?
Is it true that performance degradation in 26GHz band is more severe than 38GHz band,due to Rain?6th April 2007 at 04:45 #38390Imran SabirGuest
Kindly give me the answer that,
Why RSL(Recieved Signal Level) is in dbm while Fade Margin is in db?6th April 2007 at 05:23 #38391Imran SabirGuest
actually the selection of polarization depends upon the different prameters.
Vertical polarization is more effective against rain.
Vertically polarized waves are less effective to multipath fade in lower frequencies.
vertical polarized wave give us 30% more RSL as compared to the Horizontal polirized wave.
The reason for using both H & V polarizations is to get maximum use of frequency in th network with out interference.
Hopefully this will help you6th April 2007 at 05:52 #38392PixGuest
A received level is the measurement of an absolute power, that corresponds to miliwatts for instance. So that’s dBm.
The fading margin is an attenuation, that is a relative difference in power. And that’s not an absolute power, that can’t be express in milliwatt. It is relative… So it’s dB. A certain power – 3dB, means the power (whatever value it actually was) is divided by 2.
-6 dB = power divided by 4
– 9 dB = divided by 66th April 2007 at 06:57 #38393Imran SabirGuest
But my concern is that,
FM=Rx Sensitivity(dbm)- RSL(dbm)
if both RSL & Rx Sensitivity are in dbm,how FM is in db?6th April 2007 at 11:40 #38394TechieGuest
Hi Imran Sabir,
Thanks for your reply, i wanted to ask you one more thing that is there any distance limitation in using the H and V Polarizations in the frequency bands7th April 2007 at 13:44 #38395saadiaGuest
i want to know about path losses in GSM 1800.can anybody tell me what is the link balance?7th April 2007 at 14:48 #38396AhmedGuest
why we use in some cases vertical polarization & horizontal polarization.pls answer me7th April 2007 at 17:14 #38397WinetGuest
patrick.fr – 4 Apr 2007
Could you explain me what you meant?
ODU HS = Hot Standby?
Link is made on Ericsson Mini Link TN equipment, I’m sure there is 1+0 option checked. How ODU can be HS in this case?7th April 2007 at 19:45 #38398nizarGuest
can anybody tell me which all countries use alcatel bts for installaTION………………………………………………9th April 2007 at 04:13 #38399Imran SabbirGuest
to me it seems that your link is getting interference from some other source.Contact your Transmission Planner to verify if there is any interference on that link or not.9th April 2007 at 09:40 #38400Imran SabirGuest
Is there any distance limitation in using the H and V Polarizations in the frequency bands?
Hop distance is not dependent on the polarization,rather it is frequency dependent. Anyhow at smaller frequncies,H polarized wave suffer more multipath fading than V polarized wave,while in upper frequency bands,H polarized waves suffer more Rain fading than the V polarized waves.12th April 2007 at 10:16 #38401TechieGuest
Can anyone tell me the RSL Levels for Frequency bands12th April 2007 at 16:48 #38402pixGuest
sorry for the late reply.
by substracting two powers, you obtain a delta of power.
And a “delta” is an attenuation…
dBm – dBm = dB
a dB is a difference (or “delta”) between two powers expressed in dBm. Maybe you should refer to wikipedia if you want a more mathematical approach of this…