lnb problem

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tonguetwister_842

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Jul 7, 2009
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usa
Hi
I have been having problems with A QPH-031 LNB, what it has been doing is it would work well for from 5 min to 10 hrs and then lose signal.
I was thinking it was a problem with my coolsat 5000,since it gave me A good excuse to upgrade my system I just bought a micro hd and love it(Thank you satellite av).
The problem still happened so I replaced the lnb with an avenger pll321s-2 and now it is working properly.
My question is if anyone thinks I might be able to fix the old lnb to keep for a spare, or should i just ditch it.
Thank for being here with such a great forum.
 

northgeorgia

SatelliteGuys Pro
Nov 14, 2011
1,533
190
North GA
Something similar happened to me. In my case, I had a problem with my LNB last summer. When I removed it from the dish, I saw this webbing all over it, so apparently some tiny insect thought it would be a good idea to hatch its millions of offspring right there. Not so lucky for my lnb, because it did have a couple of tiny holes right where under the webbing and I can only imagine they had crawled inside. Anyway, I cleaned it up, brought it indoors and left it for a few months. I just tested it today for a few minutes, and it was fine (I'm hoping the bugs "left the building" and died)...but I haven't tried it beyond that. So, I'm assuming it's probably ok now.
However, my story is probably a bit of a freakish tale -- I doubt many lnbs have gotten sick because of insect invasion :)
 

SatelliteAV

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Sep 3, 2004
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Roseville, CA
If you do a blindscan after the LNBF heats up, you probably will find that the LO frequency is drifting and transponder frequencies will not be the same as a blind scan when the LNBF is cold.. Older DRO type LNBs drift with age and temperature beyond the range that receivers are able to compensate.

If the LNB frequency is drifting more than 3mhz, time to discard.
 

tonguetwister_842

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Jul 7, 2009
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usa
The lnb has been doing this for a while, day or night doesent seem to matter.
when i turn the stb off and then back on it would work again, I figured the p/s was dying on the coolsat.
sometimes just changing transponders and back again helped.
 

SatelliteAV

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Sep 3, 2004
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Roseville, CA
Sounds like thermal (heat/cooling) is causing the frequency to drift beyond the automatic fine tuning range of the satellite receiver. Retuning or power cycling will typically force the tuner to search and lock the signal.
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
2
40 miles NW of Omaha. Omaha?
Tonguetwister,

That is a fairly high dollar LNBF. I would recommend verifying if the LO drift is the actual cause before you pitch it. Erase all the TPs logged in on a specific sat and when the LNBF is cool, like early in the morning when it hasn't been powered up for more than a few minutes, BLIND SCAN the satellite. Write down all the frequencies logged in and then let it get get and warm under normal operation, preferably on a warm day after running for many hours. Then delete all the TPs from that same sat and re- BLIND SCAN the sat and compare the TP frequencies to those you logged in when it was cold.

RADAR
 

tonguetwister_842

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Active SatelliteGuys Member
Jul 7, 2009
15
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usa
The lnb is 7-8 yrs old, it sat for about 3 yrs before I put it up. I have powered it down for a day at a time several times. Time of day or time of year doesent seem to make a difference.
 

tonguetwister_842

Thread Starter
Active SatelliteGuys Member
Jul 7, 2009
15
0
usa
Well it might not be the lnb.
It was saying no signal when I got up this morning,so I will get new coax and ends when I go to town next week.
Hopefully will solve the problem, I figured the coax on the big dish would go first, it has a much longer run.
Keeping my fingers crossed, not much else I can replace,except the motor.:rant:
 

AcWxRadar

SatelliteGuys Pro
Apr 26, 2006
4,575
2
40 miles NW of Omaha. Omaha?
Well it might not be the lnb.
It was saying no signal when I got up this morning,so I will get new coax and ends when I go to town next week.
Hopefully will solve the problem, I figured the coax on the big dish would go first, it has a much longer run.
Keeping my fingers crossed, not much else I can replace,except the motor.:rant:
Tonguetwister,

Be sure to pick out the best quality RG-6 cable and connectors you can obtain.
You can get most everything at one stop on the net through Tech Tool Supply:

http://www.techtoolsupply.com/?gclid=CNK16pyZw7UCFa1AMgodUEIAIw

I recommend the compression type connectors.

http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=EX6XLPLUS_50

Hope you have a quality cable stripper and compression tool. If you don't have them already, spend the money for a good set of these tools.

http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=SKY25322

http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=CAT-AS-EX

From your NAPA auto parts get some dielectric grease for the connectors to deter moisture entry and corrosion:

http://www.napaonline.com/Catalog/Result.aspx?Ntt=765-1190&Ntk=Keyword&Nty=1&Dn=0&D=765-1190&Dk=1&Dp=3&N=0

I would not bother with quad shield cable, it isn't generally necessary and it is more difficult to work with.

RADAR
 

tonguetwister_842

Thread Starter
Active SatelliteGuys Member
Jul 7, 2009
15
0
usa
I already have dialectric grease and the tools for the compression ends.
I need to go to town on tuesday anyway so will pick up coax then and will replace the run from the receiver to the motor and from the motor to the lnbf.
If its the motor then I will be watching 97w for a while I guess.
 
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