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RE: Unity ebNo question
To: "CRTech" <crtech@crtech.org>
Subject: RE: [CRTech] Unity ebNo question
From: "Sherrod Munday" <Sherrod.Munday@SkyAngel.com>
Date: Fri, 1 Dec 2006 12:57:16 -0500
On Friday, December 01, 2006 11:42 AM, RH from WEJF wrote:
> I have a curious Unity situation that started this week (at 
> WEJF Palm Bay).
> 
> EBno's are 10.4, yet it's rebooting every minute or so.
> 
> I believe it was posted that EbNo's are not necessarily an 
> indication of a happy receiver.  They are an indicator, but 
> not the gospel truth about what's goining on inside.

Unplug the RF input and see if it continues rebooting.  You might need to unplug the power and let it cool down completely and then plug the power back in without the RF input.  If it keeps rebooting at that point, it gets to go visit Duluth, GA in a brown cardboard box.  

In other words, it will need factory service.

If it only reboots when the RF is applied (okay, and when the power is also applied ;-), then you likely have a lot of RF hash on the input.  The U4k will occasionally see excessive noise on a desired signal and "interpret" that noise as the possibility that the program loaded into the RAM of the receiver has been corrupted, so it self-reboots (because of the internal watchdog) in an attempt to re-load the code back into the memory of the receiver.

If it does only reboot with RF applied, you should really get a spectrum analyzer and verify the integrity of the RF input.  There's no other reasonable or good way to check this problem out -- you should forget about the idea of "aligning" the dish by judging the Eb/N0 that some folks insist is okay.  In this scenario, you're best off to use a spec-an.

The other possibility is to try another receiver with the same RF feed.  Or, you could carry this receiver to another known-good downlink site and see if the problem follows the site or the receiver.

This should get you going in the right direction.
--

Sherrod Munday
<sherrod.munday@skyangel.com>
(423) 303-7026 

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