LNA Amplifiers on Video Receivers - Why this result ?
Posted 19 January 2012 - 05:40 AM
I have tried two different types of LNA amplifiers on my 900 MHZ video receivers, both times with very poor results. Both attempts were very good LNA's from reputable companies with very good specs. The latest was this one for 900 MHZ
My results were more noise in the picture, and slightly less reception of a weak video signal. I am using the standard 900 MHZ video receivers with upgraded saw filters ( no cheap chinese stuff ). Any idea why I would be getting such poor results whenever I put an LNA in the antenna line of my receivers ?
Posted 19 January 2012 - 02:18 PM
Have you got an attenuator you can use?
Posted 20 January 2012 - 06:37 AM
Posted 20 January 2012 - 02:31 PM
Amplifying then attenuating is not the point, the point is you effectively get a really good low noise front end. If you have ever done any long range CB or Ham you would find that you hear the weak signal best when you turn down the RF gain so the background noise is just about gone. If you just keep adding gain two things happen, first the signal gets lost as the noise gets louder and secondly you may well push the receiver into overload or at very least force it to work at a higher level than it was designed for and so lose performance.
Edited by Terry, 22 January 2012 - 05:40 AM.