Satellite Problem shows it's face again

[zach_morton]

Ok...awhile back I posted a problem on here about my satellite system "burping" during certain programming. I have replaced the feedline, and reaimed the dish several times, and still am getting this problem, some days worse than others. I am using a Pico-Macom Satellite DA, feeding two Starguide III receivers and one XDS-Pro unit. The problem seems to get worse around mid-morning and continues into the afternoon. Using a spectrum analyzer, no spikes or interference seems to be evident.

The only common demoninator is either the dish, or the DA. By the way, we replaced the LNB and feedline with no result.

Any clue?

 

[ontheair247]

From personal experience, I would suggest going out to the downlink antenna while somehow being able to monitor the receiver, and observe whether you see any aircraft crossing the sky while these "blips" occur. That should point you in the direction of solving this.

George Kowal CBNT
KG2KC

 

[ontheair247]

What I meant was that you want to try and corellate any glitches received on your downlink with the possibility of air traffic passing by the vicinity. You may find a corellation, if so then you would pursue obtaining an appropriate filter between your receive antenna feedhorn and the LNB.

George Kowal CBNT
Assistant Chief Engineer
Press Communications, LLC
d/b/a
G Rock Radio 106.3 WHTG-FM & 106.5 WBBO
The Breeze 107.1 WWZY & 99.7 WBHX
K 98.5 WKMK Real Jersey Kountry
Real Oldies Music 1410 WHTG-AM

 

[maineengineer]

I recall in your original thread that you said you had added some attenuation, which improved the situation somewhat. However, you didn't say where you applied the attenuation, nor what the resultant actual AG & EB/NO figures were. The AG at the receiver needs to be at least 120, preferably above 130. Even though your EB/NO may look "OK" at the receiver, i.e. in the teens, there can still be overload "spikes" from aircraft radar, etc., created in the DA itself, without the required attenuation being placed there. Any overload at the input to the DA (either fixed, or intermittent) will create its own spurs, which is enough to unlock the receiver(s) momentarily, thereby creating several seconds of muting during the reacquisition process, even if there's enough attenuation applied at the input to the receiver to bring the AG into "specs." Don't ask me how I know, or I'll tell you "How I Spent my Summer Vacation."

 

[zach_morton]

Well, I am running three different receivers, as stated in the original post. On the Starguide units, one (receiving ABC/ESPN) is 13.9 EB with 124 AG. That one doesn't seem to be affected as much. However, the box tuned to Premeire shows 11.9 EB, with an AG of about 92. We have replaced the feedline, the LNB, the jumpers from the DA, and still have this problem. Back during the previous encounter, we put the attenuation ahead of the input to the DA, and it cleaned it up.

I'm almost certain now that the dish is at fault, because it has been "tied back" by my predecessor...or in other words, guyed back on four points with wire. That and it being a wire mesh dish with a couple of the panels being damaged, lead me to believe that it's about time to replace it. I was able to get a "mostly" stable signal yesterday by realigning the dish, but as soon as the wind blows or the sun comes up or a fly lands on it, it will go back out again. About all I have left...everything else has been replaced.

Another possibility is like you say...a filter might correct some of this. Just don't want to throw money at a problem only to find out it's not the problem.

 

[Lane Lindstrom]

Zach:

Have you tried a plain splitter as opposed to a DA or amplified splitter?

Lane Lindstrom

 

[zach_morton]

yep...that's how i tested the da.