Inline amp - worth the $$ ?

[Dr_Brian_Oblivion]

Great forum!

I just bought an inline amp and istalled it close to the LNB and the signal actually went DOWN instead of Up. What gives? am I doing something wrong?

Thanks!

 

[brentb636]

I would not think that an inline amp would improve anything except perhaps your overall level. An amp is not selective about what it amplifies, so noise is amplified as well.

I've read of people using an amplified signal ONLY for the purpose of fine tuning their aim on a weak transponder, and some of that might be valid, but I can't see an amplifier actually helping a weak satellite signal become an acceptable one.
Nonetheless, I have no answer for why the signal level when down, unless the amp was loading down the receiver voltage and starving the LNB .

 

[Dr_Brian_Oblivion]

I bought the amp because I get montana PBS at around 45-49% signal and on occasion it drops out on me, so I figured an amp would at least raise the signal strength.

 

[PSB]

Over the years I have solved more problems by removing in line amps than installing them!

What size of satellite dish do you have? What noise (dB) level of LNBF do you have!

You may have to go bigger with the dish if possible! A bigger dish collects more signal!

And WELCOME to the satelliteGuys.US FTA forum

 

[Dr_Brian_Oblivion]

Thanks for the welcome.
I have a 90cm dish with the Invacom .3db lnb

What kind of signal do people with similar setup get? I had it up to 58% once and thats as high as I have ever seen it.

 

[Mr Tony]

Montana PBS is notorious for being low. I have a 30" and a .4 LNB and I've seen anywheres from 30-70 on my Pansat depending on day

 

[PSB]

I am at about 72% signal quality with a 36" dish and an Invacom QPH-031, I use the Traxis DBS 3500 receiver!

 

[brentb636]

I'm getting a 68% quality on Montana PBS right now.

Fortec Classic NA

 

[Sadie]

The LNB is your receiver front end the signal level coming out of it is usually sufficient to travel down 200ft of co-ax where the loss could be as high as 20dB before being picked up by your receiver amplified and de-modulated.
Nearly all the RF gain in the system is provided by the LNB the receiver does not have to have much in the way of sensitivity, what separates the good receiver from the not so good receivers is their ability to demodulate the weaker and/or poorer quality signal and to stay locked.
When you place the line amp next to the LNB it see several things other than the weak signal that you want, such things as RF noise and local oscillator harmonics etc. depending to some extend on the quality of the LNB. These by-product will be so strong that they drive the line amp into non linear operation producing even more electrical noise to hide your desired signal, this will cause your quality to drop after installing the amp.
The amp will work well after or in the middle of a very long run of co-ax over 200ft where it is not being over driven.

Hope I got that right

 

[Dr_Brian_Oblivion]

Thank for the info, very insightful. Guess it was a pipe dream =)