G15 troubles
- Thread starter tvropro
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Thanks for the story, pro. Interesting drama, wonder if they'll drop the scrambling on anything on 131w? I'll have to scan it once in a while lol.
today is the day. D* and Comcrap both claim they will not be affected, I just want to make sure Lost airs without a hitch
I am seeing no problems with AMC 11 so far. Everything is coming in fine. Lost is not on AMC 11. It has nothing to do with AMC 11. It's just the media not knowing what they are talking about. Don't worry Lost will be fine.
They are working together which is good.
Over 62 feet
All Satguys members need one of those today is the day. D* and Comcrap both claim they will not be affected, I just want to make sure Lost airs without a hitch
Interference will be more likely as we approach next weekend. Im sure something will exist. Look at what was going on at 133 when they were both fired up.
If your and end user on cable or pizza you will be getting what there headend dish at 131 see's. Them saying statements that they won't be affected is bs. It's being said just to calm the masses, so a revolt won't happen
The strategy might work. A 19m dish is going to have a C-band uplink beamwidth around 0.2 degrees. If they can keep AMC-11 far enough away from Galaxy 15, G-15 is going to see significantly less power than AMC-11 because it will trolling off-axis of the uplink. I've not heard it conclusively, but I thought the plan was to adjust the AMC-11 transponders for the minimum attenuation (maximum gain). This will allow the uplink power to be reduced to a minimum, meaning G-15's transponders will have even less to work with. Furthermore, having reverse polarity with respect to each other should provide decent cross-polarity suppression.
All totaled, I expect quite a lot of rejection to be generated on the uplink. I don't have any numbers other than speculation, but my back-of-the-envelope assumptions look pretty good. If I'm in the ballpark, the fact that many of those taking the downlink will have both birds in their beams will not be of any consequence. It might be very similar to having the birds 2 degrees apart as they used to be. However a few dB can make a big difference and I don't have any confidence that my guesses are correct.
All totaled, I expect quite a lot of rejection to be generated on the uplink. I don't have any numbers other than speculation, but my back-of-the-envelope assumptions look pretty good. If I'm in the ballpark, the fact that many of those taking the downlink will have both birds in their beams will not be of any consequence. It might be very similar to having the birds 2 degrees apart as they used to be. However a few dB can make a big difference and I don't have any confidence that my guesses are correct.
Hi,
I work at a satellite uplink teleport in the San Francisco area. I thought the forum might want some further info regarding the Galaxy 15 issue. We have two services on Anik F3 C-band. One is for rural telephony to Alaska, and the other is extending a computer LAN from the Japanese Ministry of Defense to the Japanese Disaster Relief Team working in Haiti.
Originally, it was thought that the Galaxy 15 satellite would create interference to these circuits as it drifted through 118.7°W (Anik F3 orbital slot). But now it is felt that we (in the SF area) won't be affected because the uplink "receive" beam to the Galaxy 15 satellite will have moved to the East of us by the time it reaches 118.7°W. That's not to mean that other teleports operating out of other areas in CONUS won't be affected.
Here are some notes from the mitigation plan:
I work at a satellite uplink teleport in the San Francisco area. I thought the forum might want some further info regarding the Galaxy 15 issue. We have two services on Anik F3 C-band. One is for rural telephony to Alaska, and the other is extending a computer LAN from the Japanese Ministry of Defense to the Japanese Disaster Relief Team working in Haiti.
Originally, it was thought that the Galaxy 15 satellite would create interference to these circuits as it drifted through 118.7°W (Anik F3 orbital slot). But now it is felt that we (in the SF area) won't be affected because the uplink "receive" beam to the Galaxy 15 satellite will have moved to the East of us by the time it reaches 118.7°W. That's not to mean that other teleports operating out of other areas in CONUS won't be affected.
Here are some notes from the mitigation plan:
- C Band payload remains active and will cause interference to other satellites as it drifts east through the arc from 133W.
- Orbital (manufacturer) expects satellite to trip off in August. Momentum build up will cause loss of earth lock ?August 23 (±20 days):
- Expected to lose earth lock then roll, deplete batteries and payload shut-off occurrence.
- Telesat (Anik F3 owner) will ensure collision avoidance using standard automated processes.
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Looks like they will be making another attempt to shut it down.
http://licensing.fcc.gov/myibfs/download.do?attachment_key=822563
http://licensing.fcc.gov/myibfs/download.do?attachment_key=822563
If I read your sweeps correctly there is no signal on 21. I was wondering if it was shutbown on T7 or if it quit working as well. Do you remember any signal there recently?
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They moved Galaxy 27 to 45° East. So there have been no signals from 129° West for a few months now.
The signals are on transponders 8, 10, 12, 14, 16 and 18 vertical, and on transponders 7, 11, 13, 15 and 17 horizontal.
The signals are on transponders 8, 10, 12, 14, 16 and 18 vertical, and on transponders 7, 11, 13, 15 and 17 horizontal.
Thanks for the info.
Seems G15 is running reverse polarity for that slot. It is supposed to be odds on vertical. May be playing havoc with small dish FTA on adjacent sats.
Seems G15 is running reverse polarity for that slot. It is supposed to be odds on vertical. May be playing havoc with small dish FTA on adjacent sats.
I'm not sure which slot you're talking about relative to being odds on vertical? G15 is an odds on horizontal, and the old G27 slot is also, as is the Anik F3 slot mentioned above.
However, as I'm mentioned in previous posts, I'm really unsure about just what affect polarity would have with respect to interferrence. These sats pretty much repeat all the same frequencies on both H and V freqs, except for the 4 MHz bands that separate each transponder. So polarity be any different for most low SR signals. Polarity WOULD affect high SR signals and analog signals though, because the 4 MHz gaps would fall right on the center of a broad full transponder signal, so it is really unclear to me just what affect this might have. As I mentioned before, it almost seems like it might be like removing the carrier to produce a SSB transmission, but in any event, I think there would be interferrence no matter whether G-15 were drifting into a slot with the same or opposite polarity plan.
But this whole topic of H on odd vs V on odd slots reminds me of when they switched from 3 deg spacing to 2 deg spacing. Things just didn't line up properly for quite a while, and still aren't quite settled, as it seems like there are a couple slots with the wrong polarity, and then at the eastern side of the arc, even the slots don't seem correct, as AMC-6 is in an even longitude, whereas the rest of the CONUS C-band arc is on ODD longitudes.
I decided to make an Excel chart of Sat/degrees/odd polarity/even polarity, just to see just how well they line up, and it actually turned out better than I thought it would. Seems like the main problem is that polarity plans seem to reverse around the Anik-F3/SatMex5 area for some reason... probably dating back to the old switchover between 2 and 3 deg spacing. Polarity plans relative to odd/even polarities haven't really been firm on Ku, since there have been very odd transponder plans, with double wide transponders, which would basically mean that you had two transponders side by side with the same polarity. So this is really only an issue with C-band, which has always had consistent 36 MHz wide transponders with 4 MHz gaps.
Anyway, just in case anyone is interested, I tried to copy over the quick spreadsheet I put together, however as you see the columns don't line up as usual, but it's almost readable. I just listed C-band sats.
Sat.....Lon....ODD.....EVEN
AMC-6 72 V H
73
KU-only 74
empty 75
76
empty 77
78
KU-only 79
80
empty 81 ?V ?H
82
AMC-9 83 H V
84
KU-only 85 ?V ?H
86
AMC-3 87 H V
88
G-28 89 V H
90
G-17 91 H V
92
G-25 93 V H
94
G-3C 95 H V
96
G-19 97 V H
98
G-16 99 H V
100
SES-1 101 V H
102
AMC-1 103 H V
104
AMC-18 105 V H
106
A-F1R 107 H V
108
empty 109 ?V ?H
110
A-F2 111 H V
112
SM-6 113 V H
114
empty 115 ?H ?V
116
SM5 117 V H
118
A-F3 119 H V
120
G-23 121 H V
122
G-18 123 V H
124
G-14 125 H V
126
G-13 127 V H
128
old G27 129 H V
130
AMC-11 131 V H
132
G-12 133 H V
134
AMC-10 135 V H
136
AMC-7 137 H V
138
AMC-8 139 V H
Thanks for the correction.
Smaller dishes depend a lot on the polarity differences of adjacent slots.
Of course, the Anik's are about .3 degrees off the "norm" but they have had those slots for a long time. Sort of like the SBS Ku group.
Thanks for the chart.
Smaller dishes depend a lot on the polarity differences of adjacent slots.
Of course, the Anik's are about .3 degrees off the "norm" but they have had those slots for a long time. Sort of like the SBS Ku group.
Thanks for the chart.
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