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Discussion Starter · #1 ·
I recently installed a CM4228 and I'm receiving all but two of the DTV channels in my area at 80+ to nearly 100 on my Dish 6000 OTA. The two below 80 are sometimes below 60 (depending on conditions) and they occasionally break up. If I install the 7775 preamplifier will it boost the signal level of the two low channels without causing problems for the higher strength channels?


Thanks for your input,

Chuck Davis
 

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ChuckD,

Quote:
Originally posted by ChuckD:
I recently installed a CM4228. If I install the 7775 preamplifier will it boost the signal level of the two low channels without causing problems for the higher strength channels?
Can not comment without knowing the signal levels of the stronger stations. If the stronger stations overload the pre-amp, then you will have trouble.

The CM7775 has a gain of 26dB & NF of 2.0dB. The Winnegard AP-4700 has a gain of 19dB & NF of 2.9dB, therefore it will not overload as soon as the CM7775.


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Wendell

Technical Services Supervisor

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Discussion Starter · #3 ·
Thanks for your reply. The only way I have to measure signal strength is the signal level bar on my display for digital stations on the Dish 6000. NBC, ABC, and CBS are all in the 80's. UPN is in the 90's. PBS and FOX are the trouble makers in the 60's and lower. When they drop into the 50's, they break up. According to antennaweb.org, all of the stations are within 10 degrees of each other at my location. I thought most preamps had a level adjustment? What are the characteristics of an overloaded digital station?


Chuck Davis
 

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Quote:
Originally posted by ChuckD:
NBC, ABC, and CBS are all in the 80's. UPN is in the 90's. PBS and FOX are the trouble makers in the 60's and lower. When they drop into the 50's, they break up.
Chuck, it seems most STBs signal level indicators is a figure of merit of the data correction needed. They do not measure the RF signal, hence no indicator for analog stations.

Quote:
I thought most preamps had a level adjustment? What are the characteristics of an overloaded digital station?
Most are fixed at a certain gain. When a pre-amp is overloaded, it ceases to operate in a linear fashion and produces all kinds of spurious emissions that can cause all kinks of problems for the receiving device. The severity will depend on the amount of overload.


I would suggest trying the Winegard AP-4700. See if you can purchase from someone that will let you return it if it does not help your problem.


Some have posted that they are using a model from Radio Shack that has variable gain. They indicate RS is a no hassle return.


Do a search here for Radio Shack, pre-amp, etc.


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Wendell

Technical Services Supervisor

MAETV


[This message has been edited by Wendell R. Breland (edited 04-01-2001).]
 

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Or, you could get the 7775 and put an adjustable attenuator at the receiver. RS sells one that ranges from 0-20dB for about $6.


Dave
 

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Quote:
Originally posted by davestill:
Or, you could get the 7775 and put an adjustable attenuator at the receiver. RS sells one that ranges from 0-20dB for about $6.
Dave, yes this will work if the receiver is overloaded and the pre-amp is not. Otherwise, the attenuator needs to go in front of the pre-amp if it is being overloaded.


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Wendell

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I have a CM4228 and the CM7775. Receiving 80 to 94 signal in Everett, WA about 50 to 60 miles from towers in Seattle. Every channel is crystal clear except KING 5.1. Numerous dropouts every 10 seconds. Running HD100. I am wondering what the anneutator will do. I have a rotor that is digialy locked in to each channel.
 
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