Hi I'm wondering why I can only see weak transponders in the night (between 9 PM to 8 AM) the rest of the they they are away.
Weak Transponders Only Seen In The Night
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Several reasons that weak transponders may only be received at night. I am sure that others will add to this list.
Hardware:
1. LNBs perform better when chilled
2. LNB LO maybe drifting and the STB may not easily lock on off-frequency and weak signals.
3. Reflector surface may distort as the material expands/retracts
4. If the dish is mounted on a structure or organic the aiming may be moved as the support materials react to heat and moisture
5. Positioning of the satellite within the box
Environment:
1. The moisture or particulate matter (smoke, dust, etc.) in the atmosphere
2. The density and positioning of different atmospheric layers
3.The solar effects (charging) to the RF properties in the atmosphere
4. TI (terrestrial Interference) may go away at night
Hardware:
1. LNBs perform better when chilled
2. LNB LO maybe drifting and the STB may not easily lock on off-frequency and weak signals.
3. Reflector surface may distort as the material expands/retracts
4. If the dish is mounted on a structure or organic the aiming may be moved as the support materials react to heat and moisture
5. Positioning of the satellite within the box
Environment:
1. The moisture or particulate matter (smoke, dust, etc.) in the atmosphere
2. The density and positioning of different atmospheric layers
3.The solar effects (charging) to the RF properties in the atmosphere
4. TI (terrestrial Interference) may go away at night
Are you talking about any particular ones, or are you just talking about weak transponders in general?
The LO in your LNB(f) probably has less drift, when things cool off. The F-Layers in the atmosphere combine at night to one.
Solar radiation is also at minimum.
What are you using?
The LO in your LNB(f) probably has less drift, when things cool off. The F-Layers in the atmosphere combine at night to one.
Solar radiation is also at minimum.
What are you using?
I think Titanium covered the 3 I figured had the biggest affect
1 Cooler lnb performs better
2 Less terrestrial interference at night
3 Less solar interference. Figure if it can cause complete outages a few times a year it is probably causing some interference at all times.
1 Cooler lnb performs better
2 Less terrestrial interference at night
3 Less solar interference. Figure if it can cause complete outages a few times a year it is probably causing some interference at all times.
Thanks guys just to explain a little bit more my problem.
I have this problem only with my 1.2 meter dish, it's pointing to 125w and the problem is happening only with 11760 H and 11800 H, the LNB I'm using is the Avenger Single Universal (PLL).
The dish is mounted on a concrete terrace roof.
I have this problem only with my 1.2 meter dish, it's pointing to 125w and the problem is happening only with 11760 H and 11800 H, the LNB I'm using is the Avenger Single Universal (PLL).
The dish is mounted on a concrete terrace roof.
I have often wondered if the PBS transponders have an intentional reduced power in their Link Budgets with the satellite owner since they use much larger dishes and have greater margins in Signal to Noise Ratios (SNR) or if their is an actual problem with the automatic monitored power maintenance or the transponder automatic power setting that only affect the hobbyists with of our smaller dishes and more critical and reduced SNR.
The satellite owner or control/maintenance group is responsible for station keeping to maintain the satellite in a specific assigned orbital location often referred to as "in the box". They also monitor both the uplink and downlink signals to make sure they are compliant to the link budget with the customer and within the satellite's technical parameters. For example the satellite control center will make sure that the uplink signal does not over-saturate, exceed the allowed bandwidth or power for the contract. The control center also can adjust the parameters for the transponder, I.E. turn on/off the automatic power level tracking. This is usually set on to maintain the satellite output signal level as the satellite moves around in the box and nears the beam edges of the uplink dish.
Uplink centers normally automatically monitor the return signal from the satellite verifying that the dish is centered in the box and uplink signal power is increased/decreased to maintain a specific output power level from the satellite. The Uplinker monitors the return signal and will increase the transmission power to provide a signal to the satellite at a contracted level. For example, the uplink operator may increase the transmit power during attenuating heavy cloud cover.
Have you tried re-tuning your dish between 9 PM to 8 AM?
Success would cover Titaniums points
3. Reflector surface may distort as the material expands/retracts
4. If the dish is mounted on a structure or organic the aiming may be moved as the support materials react to heat and moisture.
And quite possibly 5. Positioning of the satellite within the box
Try scanning the satellite between 9 PM to 8 AM?
If they 'show up' a few Mhz different frequency would be point:
2. LNB LO maybe drifting and the STB may not easily lock on off-frequency and weak signals.
1. LNBs perform better when chilled
Concrete terrace; betcha it gets HOT! Suns rays directly upon the lNBF and are reflected off the concrete to the LNBF along with heating of the concrete itself.
A possible solution. 6 inch white PVC tube over the LNBF. 'Muffin' fan also in the tube. Keep the air flowing to cool the LNBF.
I have a feeling your 'symptom' may be a combination of more than just one of the above.
Success would cover Titaniums points
3. Reflector surface may distort as the material expands/retracts
4. If the dish is mounted on a structure or organic the aiming may be moved as the support materials react to heat and moisture.
And quite possibly 5. Positioning of the satellite within the box
Try scanning the satellite between 9 PM to 8 AM?
If they 'show up' a few Mhz different frequency would be point:
2. LNB LO maybe drifting and the STB may not easily lock on off-frequency and weak signals.
1. LNBs perform better when chilled
Concrete terrace; betcha it gets HOT! Suns rays directly upon the lNBF and are reflected off the concrete to the LNBF along with heating of the concrete itself.
A possible solution. 6 inch white PVC tube over the LNBF. 'Muffin' fan also in the tube. Keep the air flowing to cool the LNBF.
I have a feeling your 'symptom' may be a combination of more than just one of the above.
About the idea of PVC, do you have seen or do you have an image explaining a little bit better to cover the LNBF with PVC
Now about the 'Muffin' fan, what do you mean with that?
By the way a little bit off topic but you have an 2.4m offset dish right? what brand is it?
Now about the 'Muffin' fan, what do you mean with that?
By the way a little bit off topic but you have an 2.4m offset dish right? what brand is it?
MUFFIN FANS
Pictures are worth a thousand words"
Cant remember the brand of the 2.4 meter at this time, and can't locate the thread with the pictures, nor figure out how to access previous uploads. I'll figure something out and get back. I DO remember that it IS heavy. Mount fits a 7 inch O.D. pipe(IIRR)
Pictures are worth a thousand words"
Cant remember the brand of the 2.4 meter at this time, and can't locate the thread with the pictures, nor figure out how to access previous uploads. I'll figure something out and get back. I DO remember that it IS heavy. Mount fits a 7 inch O.D. pipe(IIRR)
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Thanks for the image, the only problem I see is where to power the FAN, I don't have any sort of electricity in where I have the satellites so I think I'm gonna first try something without the fan, something like an umbrella for the LNB.
About the 2.4m I hope you find your thread/pictures and who knows maybe we can make some business
About the 2.4m I hope you find your thread/pictures and who knows maybe we can make some business
You may be seeing the effect of interference from a transponder on an adjacent bird (like 123 or 127W) with overlapping bandwidth in the same polarization that is only turned on during the day. Smaller dishes, even 1.2 m on Ku, are more vulnerable because of their wider beamwidth, and 8PSK signals like 12180 V 30000 on 125W are more sensitive to the phase noise degradation this causes. I haven't checked recently, but this situation used to be the case for 12180 on 125W.
After checking out what you've said, I've found that there's no other H frequencies that could be interfering with 11760 H and 11800 H so maybe 12146 H, 12155 H, 12163 H, 12169 H, 12175 H are interfering when they are turned on in the day, correct me if I'm wrong
You probably won't be able to look at a "what's up there" list to determine if there occasional use signals that could interfere. You would need to blind scan the adjacent satellites for compliant DVB transmissions or view with a spectrum analyzer to identify any type of RF signals. Interfering RF from adjacent satellites may not be a full-time service listed on a channel list, might be a DVB data service or not even be DVB compliant.
Hard to say, but in the satellite world, bigger is better...
Post #2, #7 and #11 pretty much sums up the factors that may come into play. Only testing will start narrowing down the why and how...
After getting the signal from this low transponders I have to say that when I can tune them are stronger than the weaker "V"
In other words 11980 V gets 44% when 11800 H gets 68% so I was wrong those H transponders are not the weakest ones, the weakes one is 11980V which I'm able to tune it no mater is day or night or even at cloudy and rainy sky.
In other words 11980 V gets 44% when 11800 H gets 68% so I was wrong those H transponders are not the weakest ones, the weakes one is 11980V which I'm able to tune it no mater is day or night or even at cloudy and rainy sky.
Some transponders on AMC21 are on the North American beam and others are on a Caribbean beam. There have been several discussions, which I agree, that Lyngsat is in error with listing 11980 on the Caribbean beam. Some transponders are very fat (wide bandwidth) and others are narrow bandwidth. The FEC are not extreme, but these are DVBS2 signals and require better signal quality than DVBS type. I would expect the fat Claro transponders targeting Direct To Home small dishes to be easier to receive than the narrow PBS transponders with a link budget to be received with verily large dishes at commercial downlinks.
Many folks have reception issues with 125w and much speculation swirls as to why some have reliable reception with a 76cm dish and others have unreliable reception with much larger dishes. You are not alone.
Many folks have reception issues with 125w and much speculation swirls as to why some have reliable reception with a 76cm dish and others have unreliable reception with much larger dishes. You are not alone.
Thanks for the image, the only problem I see is where to power the FAN, I don't have any sort of electricity in where I have the satellites
Mount a small solar cell with voltage regulator circuit near the dish and run wires to cooling fan. If designed properly unit will even turn itself on when sun rises and off when sun sets or could be set to run continuosly if needed.
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