Combiner Loss

[islam wagih]

Dear Friends,
Why combiner has 3dB loss?

Also;

Why TMA has Gain for Uplink and Loss for Downlink?

Kind regards

[giegala]

Hi,

it is because on RF feeder and RF jumper both UL and DL signals are transferred. However TMA amplifies only UL signal, therefore it requires diplexers to extract UL signal and bypass DL one. So these diplexers bring in some loss for DL. That loss is rather small - 0.3 dB.

[islam wagih]

Dears,
Anyone has more details and clarification please?

[Stantheman]

The RF Combining principles between Land Mobile Radio and Cellular are very similar, so have a look at the information at these sites:-

http://www.repeater-builder.com/antenna/ant-sys-index.html see a 1/4 of the way down the page:- "Combiners" , there is a massive amount of good information at this site http://www.repeater-builder.com/rbtip/

Good papers on the subject also here http://www.emr.com/techinfo.php


BR's Stan.