# OTA Geniuses... Help Me out with upgraded preamp



## Cokeswigga (Jan 25, 2005)

Here is my current Setup:

Winegard HD-9095 with AP-4700 Preamp.

I live in southwest riverside, and I have my antenna aimed at Los Angeles' Mt. Wilson Antenna farm. It's about a 70 mile journey as the bird flys from my antenna to the transmission antennas

I am able to tune in all L.A. Channels.

Primarily these are the stations of interest
Channel**********UHF*****Strength with AP4700****Strength with 4800
002-1 (CBS Digital)**60**********96********************94
004-1 (NBC Digital)**36**********79********************73
007-1 (ABC Digital)**53**********77********************56
011-1 (Fox Digital)***65*********78********************74

I just bought an AP4800 (higher gain pre-amp)
I was hoping that with the 4800, I would get better signal strength on all the channels. 

Instead I saw the opposite. I lost a few points. No big deal, I attributed it to the increased noise of the pre-amp or something.

But what really caught my eye what I totally lost channel 53 (kabc-DT 007-1)

Now, here's a little history. 
I used to have a Dish Network 811.
With the 811 I had all kinds of problems tuning in ABC. 
What I found was that I turned my antenna 90 degrees to the west and point it at a nearby mountain, I could get kabc, but at a low signal (~60). So I attributed the inability to tune in KABC to multipath from the mountain. BUT it only affected this one channel!!! None of the other channels had any problem of signal issues.

So I turned my antenna back to pointing straigh at mt wilson, and just accepeted that I would have to move or blow up the mountain, or wait until a better ota receiver came out.

Low an behold, a little patience paid off. (and since blowing up a mountain would probably piss off a bunch of people), I upgraded to the Dish Network 622... which has a much better OTA receiver. All of a sudden I was able to tune KABC without any trouble. 

Now today..... my questions are:

1.) Why did I not see much of change at all on all the channels with a higher gain pre-amp?

2.) Why does the higher gain pre-amp significantly effect the one channel (possible multipath)?

3.) Why does only the one channel have this problem with multipath??


Or am I totally off my assumptions.. 


Any help would be greatly appreciated.

Thanks


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## Cokeswigga (Jan 25, 2005)

UPDATE:

I removed the pre-amp and discovered that the receiver gets signal without ANY pre-amp.


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## n3ntj (Dec 18, 2006)

Its possible the pre-amp may overdrive your receiver and end up looking worse than barefoot (with no pre-amp).


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## n2ubp (Jan 11, 2007)

What is the signal to noise ratio of the preamp ? Have any pager antenna farms in your area ? Sometimes you can overload a preamp with RFI from other sources.


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## Cokeswigga (Jan 25, 2005)

The AP4800 was overloading the signal. 
So I revmoved it.

I did not re-install the 4700 as it is not needed.


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