Feeder sweeps

[wolverine]

Hi guys,

Does anyone have any documentation on feeder sweeps? What is typically measured, what equipment is used etc.

I am especially curious about the measurement of the feeder loss. How is this calculated considering you might only have access to one end of the feeder (by the cabinet)?

[luganomu]

Sweep meter ie anritsu site master
Measurements are VSWR and Return loss, But VSWR <=1.3, Return loss >16db

[mohyedeen_alkousy]

Hi guys,

Does anyone have any documentation on feeder sweeps? What is typically measured, what equipment is used etc.

I am especially curious about the measurement of the feeder loss. How is this calculated considering you might only have access to one end of the feeder (by the cabinet)?

path balance measurements will be helpful in feeders problems
also check alarms of VSWR

[harrypotter]

anything that goes above your limit line is an issue... use marker to peak or valley to see the reflection...

[wolverine]

VSWR I understand, but what about feeder attenuation? How is this measured?

[Stantheman]

this should help http://downloadfile.anritsu.com/RefFiles/en-US/Services-Support/Downloads/Application-Notes/Application-Note/11410-00276.pdf

also http://www.mrtestequipment.com/getfile.php?s=Anritsu+Site+Master+S332C+Antenna+Cable+and+Spectrum+Analyzer+Users+Guide.pdf

[wolverine]

Ok reading the documentation provided it seems that the only way to measure feeder loss is to put a short on one end of the cable. So in a system that is already installed, I guess this means someone has to climb the mast, disconnect the antenna from the feeder and place a short in its place. Is this your understanding too?

[harrypotter]

Its not necessary that you have to climb and put the dummy load. If you know how to read and interpret the sweep for the whole system your well off. But if you want to check feeders and jumper not including the TMA's, etc... then you need to put the dummy load.

[adewijaya]

Ok reading the documentation provided it seems that the only way to measure feeder loss is to put a short on one end of the cable. So in a system that is already installed, I guess this means someone has to climb the mast, disconnect the antenna from the feeder and place a short in its place. Is this your understanding too?

not necessary i think, using Distance to Fault to know what's range that having some trouble in there :)

[indoor]

I thought that if you know the type of cable the site master would tell you the loss based on the length. You can usually see this on the Distance to fault sweep as there will be a small blip at the antenna connection.