POSSIBLE LOSS OF LNB

Discussions about low-noise blocks, waveguides, horns and other components used at the prime focus of your reflector dish.
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nanirdjeff
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POSSIBLE LOSS OF LNB

Post by nanirdjeff » Wed Nov 27, 2019 8:39 pm

I have lost about 50 percent of the stations viewable on 97, 99, 101,103 West. This happened overnight this week. When I did a re-scan, I got the same result - most of the stations did not show up on the scan. I checked my alignment east/west, and the vertical and horizontal. Still got the same result. Any suggestions as to what may be causing this?

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Re: POSSIBLE LOSS OF LNB

Post by fatso » Thu Nov 28, 2019 2:54 pm

Are you using any kind of switch? If so bypass it to see if that is the problem. I would also check the f connectors on the coax. If you recently experienced high winds they may have moved your feedhorn/lnb/scalar ring. Check it and make sure it isn't tilted or off bore sight. It happens a lot with button hook feeds.
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nanirdjeff
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Re: POSSIBLE LOSS OF LNB

Post by nanirdjeff » Fri Nov 29, 2019 10:59 am

I am not using a switch. I will try to check the F connectors at the lnb - but at 82 years young - this may be a bit difficult. Can you explain what you mean by - "button hook feeds"? I have also tried the system with two other satellite receivers with the same result.

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Re: POSSIBLE LOSS OF LNB

Post by mux » Fri Nov 29, 2019 11:58 am

Not button hook feeds he is referring to a button hook dish. A button hook dish is the type that the has a single arm that goes through the center of the dish. The arms can turn and throw the LNB skew off. Now that has me thinking about about my signal loss problem.

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Re: POSSIBLE LOSS OF LNB

Post by tvroadmin » Fri Nov 29, 2019 11:58 am

nanirdjeff wrote:
Fri Nov 29, 2019 10:59 am
Can you explain what you mean by - "button hook feeds"?

Do you have 3 or 4 strut arms that hold the scalar ring or a long post attached to the center of the dish and bent like the letter C near the focus which holds the scalar ring and allows you to adjust it up/down? The latter is a button hook. Look at your scalar ring and make sure it is pointing at the center of the dish otherwise your dish illumination may be off. I had this problem once after hurricane gale force winds passed through my area. Signal dropped on almost every transponder. I went to the dish and grabbed the scalar ring with both hands and gently bent it back in place. Even a 5 degree misalignment of the scalar ring may cause serious signal degradation.

If you have strut arms holding the scalar ring, then it should be perfectly centered. Still, I would go to the dish with a signal meter, grab the scalar with both hands and gently bend up/down and left/right to see if performance improves any.
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Re: POSSIBLE LOSS OF LNB

Post by nanirdjeff » Sat Nov 30, 2019 8:59 am

Thanks for the replies. It is scheduled to rain for the next few days here in Fort Worth, Texas, so will inspect on first sunny day and let you know of the result. Thanks again.

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Re: POSSIBLE LOSS OF LNB

Post by nanirdjeff » Sat Nov 30, 2019 2:53 pm

Sun is out. Took cover off system. The two lnbs have been sealed with glue (or something). I took the following photographs of the set up. Hopefully I can attached them to this email.

This is the information on the LNBs:-

1. Microwave Low Noise Converter - Model # LP 5000K - Platinum - 11.7-12.2 Ghz - 57 Db. - (Nearest the front)
2. Eagle Aspen SLT - Extended C band LNB - Fre range = 3.4 - 4.2 Ghz - Gain = 65 Db. - (At the back)

I have had this C band set up since about mid-1994. I know that the system has been periodically updated through the years, however I do not recall when the lnbs were last updated and cannot find any paper-work in this regard.

Any suggestions?

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Re: POSSIBLE LOSS OF LNB

Post by tvroadmin » Wed Dec 04, 2019 3:56 pm

Could your problem be related to 4g/5g terrestrial interference? Did any new microwave towers go up in your area? Are you near an industrial area or airport? If your Ku band works like before but your C band is experiencing problems, it might be related to this. If you don't suspect interference, you might just want to invest in a new LNB.
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