VSWR

[RF-MAN]

hi dears


I have a problem to measuring of VSWR bye site master.

I measuring vswr but i see a strange thing.

please help me ?

what is vswr at the picture more other places ?
31725


if feeder has problem ?


thanks


i am waiting for your help

[justdream]

You have big problem at the end of your test line
measure the distance to know where this problem exactly - I think you could get distance by checking DTF

[RF-MAN]

i checked path of feeder and didn't find problem....

can i change RX with TX from bottom antenna then measure vswr ?

[justdream]

was your site master snapshot when you made test with Dummy Load or without?

[RF-MAN]

when made test site master was with load. .....

if maybe antenna was broken ?/?/

[justdream]

site master with Load :so Antenna hasn't been included in your test"
as Load was at the end,
Am I right

[RF-MAN]

DEAR JUSTDREAM

please see below picture .....

i hope you understand that I want to explain??/


31731

in this regard antenna is ok or not?

i want understand that antenna is working normaly or not?

[justdream]

based on your drawing:

- you didn't use load
- your site master snapshot is normal as having antenna at the end giving this chart
- Do another test but in this time connect load instead of antenna

[RF-MAN]

what do you mean from load ?

load=????

i didn't understand your mean from load???

[justdream]

load is Dummy load
you add at the end of you site master connections to have an accurate measurement

http://2.imimg.com/data2/BD/TC/MY-5443/dummy-load-5-watt-din-male-connector-250x250.jpg

Take care and be sure not to fall it as it's very sensitive

[RF-MAN]

i didn't use dummy load ........

i use site master with conector that joined with feeder .....

please say to me application of dummy load?????

[justdream]

"When you connect the dummy load all the energy absorb in the load. So if there is a fault you can see the reflected signal from it. But if you measure it with antenna connected, some energy reflected, and interfere with the reflected signal from the fault so if it's a weak signal you will not be able to see it. Using load in a sort of way increase the accuracy of your test"

[RF-MAN]

all your words are true but if antenna has problem and faulty maybe when we measure vswr by site master meet with above graph ???

i want know that antenna doesn't have problem???

feeder has problem or antenna ?


thanks a lot dear justdream

[qwertry]

Hi,

Based on my experience with VSWR measurements i can give you following advises:
1. Calibrate Anritsu Site Master together with Anritsu jumper before to start to measure.
2. Set valid RF band (GSM900 890.0–915.0/935.0–960.0), check that all RF component have same RF band, specially antenna, surge arestors and TMA.
3. If you have Xpol antenna, disconnect both ports from BTS/RBS.
4. Good feeder path together with antenna have VSWR below 1.5
5. Check DTF, select your feeder model from list in Site Master, set expected length, highest value (peek) must be in end of feeder line (in antenna).

From attached picture i can say that you have problem on feeder line close to BTS (may be RF connector), or you have surge arestor on feeder line and your Site Master settings are incorrect. Visit Anritsu web site there you will find very useful docs how to measure VSWR.

BR