Signal fade question

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comfortably_numb

comfortably_numb

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Ok, so as you guys may have read, I've been running 4 LNBF's on my 90cm GeoSat pro dish. It's focused on 103, then I have LNB's on 97, 91 and 87.

The signal on 103 and 97 stays consistent 24/7. For some reason I get signal fade on 91 and 87 in the mornings. It returns in the evening after about 5 or 6. This happens even if the sky is clear and sunny.

What would cause signal fade during the day, but come in strong at night?

IMG 0285
 
Magic Static

Magic Static

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You are right on the threshold of "lock" on signal. The background noise will rise and fall during the day and drown out the signal you get when conditions are optimum.
 
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comfortably_numb

comfortably_numb

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So I should peak the dish in the morning then? It's a pretty big difference. We're talking zero signal strength and signal quality at 9 AM, then 98 signal strength and 47 signal quality at night!
 
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a33

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And if the problem is dependant on temperature change, I suspect drifted (unstable) LOF.
Easy to test, by changing the LOF in your receiver by about 4MHz (up or down), and check if that brings improvement.

greetz,
A33
 
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Titanium

Titanium

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Signal level readings only means that the LNBF amplifier is working. It is not an indication of the signal being received from the satellite. The only meter reading that displays the satellite signal is the Signal Quality. On the Amiko RE and h.265 receivers tuned to this transponder, 47% Signal Quality reading is VERY LOW and just above the threshold of not being received. I highly doubt that the issue is related to LNBF drift.

You might try to peak the two offset LNBFs when the signal is weakest, but with the dish centered on the 103w satellite, 15 degrees offset is getting off-center enough to have very poor efficiency on weaker signals. You might try instead to center the dish on the 97w satellite and putting the offset LNBFs on either side. This will bring the 87 and 91w satellites closer to the sweet spot that the dish is designed for. Also, try slightly raising the offset LNBFs feedhorn openings to optimize the Signal Quality readings.
 
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comfortably_numb

comfortably_numb

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Signal level readings only means that the LNBF amplifier is working. It is not an indication of the signal being received from the satellite. The only meter reading that displays the satellite signal is the Signal Quality. On the Amiko RE and h.265 receivers tuned to this transponder, 47% Signal Quality reading is VERY LOW and just above the threshold of not being received. I highly doubt that the issue is related to LNBF drift.

You might try to peak the two offset LNBFs when the signal is weakest, but with the dish centered on the 103w satellite, 15 degrees offset is getting off-center enough to have very poor efficiency on weaker signals. You might try instead to center the dish on the 97w satellite and putting the offset LNBFs on either side. This will bring the 87 and 91w satellites closer to the sweet spot that the dish is designed for. Also, try slightly raising the offset LNBFs feedhorn openings to optimize the Signal Quality readings.

What’s a good transponder on 97 to peak with? Something weak so I can fine tune
 
Titanium

Titanium

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On 97w use any TP other than 11842 (adjacent satellite interference requires the reflector to be dithered West to Peak this TP). Go through your TP list and find the weakest TP for you and peak the Signal Quality reading. The weakest TP may vary by region as each polarity and TP link budget will result in a different footprint.
 
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comfortably_numb

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Well folks, I gave it a valiant effort. I focused the dish on 97, put 103 on one bracket and 91 and 87 on the other. I was able to get the strong transponders on 103, but none of the NBC's. Those NBC feeds are really touchy and seem to require the dish to be head-on. I enjoy watching them too much to sacrifice them for a better signal on 87.

I'm not complaining, though. Getting CNN feeds on 87 (at night), 91, 97, 103 and 105 (Macy's) is pretty good. I'm happy :)
 
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a33

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Looking at the picture in your openingpost, I wonder:
Do you have enough room for your LNBs, to be placed next to each other? Or would you be better off with one or more 'thinner' LNBs?

And does it look like your byrider LNBs have an aiming direction parallel to the central LNB? In that case they might be looking partly outside off the dish. Better would be if they are aiming more to the vertical center of the dish, to a point on the dish about 2/3 of the distance between LNB and central LNB away from the parallel aiming line (rule of thumb).

greetz,
A33
 
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