- This topic has 6 replies, 1 voice, and was last updated 11 years, 10 months ago by David.
21st December 2008 at 07:31 #55105JacubsGuest
I am trying to measure the VSWR of a DCS 1800 cell, and all I get is unreasonable measurements. Please, guide me for this problem.
Thanks.26th December 2008 at 11:17 #55106jamilGuest
We always take 2 test in vswr machine one for distance to fault
Another one for measure match ( frequency )
If u are calibration the bird machine or any machine at 1800 .
You suppose to do the this thing .
First calibration must be full .
Second test the frequency by press on auto if its gave u more them 1.5 for limit line means the feeder is dirty at contactor .
Third distance to fault u must see the damage in connecter or feeder some time the contactor not preparing good and must be less them 1.05 for limit line10th January 2009 at 14:04 #55107finnGuest
I remember, you should have a 1.4 VSWR limit on your SiteMAster and 1.5 for scaling. If you over the 1.5 and that is not acceptable. How does your DTF looks like? I hate DCS..19th January 2009 at 19:12 #55108Furqan MahmoodGuest
what is a vswr..?
wot we do wid it?wot we measure..?
why vswr reading more dan 1.3 is nt good .?21st June 2009 at 10:41 #55109finnGuest
The MTN want the limit line 1.6 for 1800mhz and 1.5 for 900mhz if u have diplexer for the (VSWR)
And the better diplexer u will not face any problem when u used it is Kathrein .
1.5 for 1800 mhz and 1.4 for the900mhz but most time i get between 1.3-1.4 and its good26th June 2009 at 07:03 #55110jamilGuest
sorry finn i write ur name up in the vswr for mtn4th July 2009 at 06:09 #55111DavidGuest
Definition of VSWR – Please refer some of your older books.(frankly i too dono.)
Coming to the practical point. I hope you are having a VSWR meter. First check whether the frequency band is in 1800 Mhz. Mostly the range may be in 900 band n u may get false reading. Next, for DTF (Distace to fault)first give the app. distance of your comlpet cable length. most meters will have D1 and D2 points where in u can give the distance; the meter has to measure.
Normal values has to be 1.4 for VSWR and 1.04 for DTF. If u get a value say 64.5 VSWR it means that the port is opened somewhere. u can also say that the signal which was sent by VSWR meter has not all returned back. Ultimately the job of a VSWR meter is to send a signal n check the value of signal returned and if not, the measure of signal loss, n also the distance where the signal is lost.
if u get a a very high level VSWR, then disconnect the cable from vswr meter, n connect an omni/bulb type of antenna(2dBi) antenna n check the value, this i to know whether the value that u get once u connect to the cable is right.
hope u r atleast a bit clear.