- This topic has 58 replies, 1 voice, and was last updated 13 years, 9 months ago by Da Architect.
30th March 2007 at 21:17 #42232GeorgesGuest
Guys, Does anyone knowWhat is the frequency separation formula between 900 and 1800 to avaid modulation between the 2 layers. Thanks7th April 2007 at 14:29 #42233AhmedGuest
I can use passive repeater for GSM mobile phones,But I don’t know which type must be use,if its unpossible, I can use active repeater? please help me
Best Regard8th April 2007 at 10:54 #42234AhmedGuest
can anybody tells me what is the meaning of Gaussian minimum shift keying(GMSK)in GSM network?8th April 2007 at 16:08 #42235SAMBITGuest
Hii GMSK is a modulation22nd April 2007 at 10:59 #42236AhmedGuest
Hi SAMBIT,I konw the GMSK is a modulation but my question mean in which method it work, it’s like PSK or BPSK or what??
Best Regard24th April 2007 at 11:49 #42237SambitGuest
Gaussian minimum shift keying or GMSK is a kind of continuous phase frequency-shift keying. The baseband modulation is generated by starting with a bitstream 0/1 and a bit-clock giving a timeslice for each bit. This is the type of modulation used in Global System for Mobile Communications (GSM) – although that system includes differential encoding of the bitstream, which makes the overall modulation behave like a kind of continuous phase Binary Phase Shift Keying with constant envelope.25th April 2007 at 06:01 #42238ArsalGuest
What should be the prefered front to back ratio of 65 deg high gain GSM Antenna & why?
Thanks25th April 2007 at 09:24 #42239Paul FlemingGuest
Could anyone please explain what is meant by 30bd separation in regards to dual and triband GSM RBS antennas. I do understand the need to avoid interference but how is it done?30th April 2007 at 05:45 #42240shellyGuest
Can anly one tel me about AM,FM,PM or name the book which defines the these terms in complete discription.
Thanx7th May 2007 at 06:05 #42241AhmedGuest
My network now work under GSM900 and GSM1800 if my company supported CDMA what is devices must be replaces,whay?
Best Regards7th May 2007 at 11:22 #42242PixGuest
It depends on your vendor, but normally you can’t reuse any of your GSM network elements in a CDMA network… Maybe you can reuse the antennas if it’s in the same frequency band 🙂
In best case, you can also reuse the BTS cabinet, and fill it up with CDMA equipments…12th May 2007 at 11:25 #42243yashGuest
how could we define the antenna direction12th May 2007 at 19:24 #42244PixGuest
Antenna orientation is the azimuth facing the antenna (north = 0, south = 180, etc), where the gain of the antenna is maximal.22nd May 2007 at 04:36 #42245AhmedGuest
if a mounting two antennas for GSM900 one of each in high 20meter and the other in high 45meter but in same direction and used same band (900MHz),do you think may be happen interference between them,why?
Best Regards22nd May 2007 at 08:12 #42246PixGuest
With 25m of vertical separation, you will not experienced interference, unless you use the same GSM900 channels (co channels or adjacent channels).
There is absolutely no problem here…