Adjacent sat problem

[7720driver]

Many times, when I blindscan a satellite, it will pick up transponders on an adjacent satellite. Even though that satellite is two degrees away, the signal is still strong enough to produce a good picture.

Of course I can simply go to Lyngsat and see which satellite each channel is really being broadcast from, and then just delete the bogus channels from their listing on the incorrect satellite.

That's a somewhat laborious task, though.

It would be a lot better if I could just program my receiver with the correct transponder frequency and polarity information for each satellite. Then I could do a regular scan (not a blind scan) and find all the correct channels and none of the channels on the adjacent satellites. At least that's my thinking. Someone correct me if I'm wrong. I guess I could use Lyngsat info to manually enter the transponder data for each satellite, but that would be a big job

My question is: Is there a way to download transponder and polarity information for each satellite from the internet.....download it in a format that is usable by a by a FTA channel editing program such as Channelmaster. From there I could send the information to my Coolsat 5000.

Would that work? Is there a place to download such information in a usable format?

 

[W_Tracy_Parnell]

The problem is that most satellites are constantly changing, so even if you have a TP programmed in if the symbol rate changes you are out of luck. I still hit Nimiq when I blind scan IA6, even with a linear LNB. I just live with it.

 

[123tim]

Many times, when I blindscan a satellite, it will pick up transponders on an adjacent satellite. Even though that satellite is two degrees away, the signal is still strong enough to produce a good picture.
I

This has me wondering....Do active channels on one satellite ever interfere with active channels on an adjacent one?

Thanks.

 

[Mr Tony]

This has me wondering....Do active channels on one satellite ever interfere with active channels on an adjacent one?

Thanks.

it screws with the signal...look at 11720 on G10. That should be the same signal as 11800 but due to Dish 121 having a signal at 11724 Vertical it overpowers the signal on 11720 (G10). 11800 doesnt have that issue because Dish 121 has a H tranponder at 11800

Last year we had the same issue with North Dakota hockey. They were on G3 but the transponder they were on there was a stronger one on either IA6 or IA5 (I cant remember) that made people with 30" dishes get squat for signal. You needed a bigger dish.

But to the OP..doesnt sound like you're exactly dead center on the satellite. I notice when there is bleed over from an adjacent satellite, I just readjust the motor (nudge it one click E or W) and that clears it up

 

[Stefan]

But to the OP..doesnt sound like you're exactly dead center on the satellite.

Bingo! Problems of intereference from adjacent satellites are largely the result of either improper alignment or using an undersized reflector. Scaler ring or focal point adjustments may also play some role as improper adjustment with regard to these could perhaps increase the amount of energy picked up by the feedhorn from sidelobes off of adjacent satellites.

This has me wondering....Do active channels on one satellite ever interfere with active channels on an adjacent one?

Absolutely, if your dish is too small or not properly aligned. This is why it's important to always use as large a dish as possible. Larger dishes have a narrower beamwidth and won't suffer as much form interference from adjacent satellites. It's also important to note that when we talk about a dish having a certain beamwidth it's doesn't mean that the feedhorn will recieve no signal at all from an off axis signal coming from a satellite outside of it's beamwidth. It just means that those signals receieved will be degraded enough that they won't interfere too much with the intended signals coming from the satellite your aimed at. Signals that use higher orders of modulation, like 8psk or 16QAM, or signals that use FEC rates desgined to squeeze out more bandwidth will be more sensitive to noise from adjacent satellites and will require dishes with even narrower beamwidths and very accurate alignment of those dishes. If you ever drive by your local FOX affiliate notice the size of the dish they have in their backyard. There's a reason for that.

 

[123tim]

If you ever drive by your local FOX affiliate notice the size of the dish they have in their backyard. There's a reason for that.

That's something that I've wondered about. Thanks!

 

[7720driver]

I was aware of the fact that... the larger a dish, the tighter its focus...and thus the greater its ability to reject signals from adjacent satellites.

From the things I've read, it sounds like some dishes are shaped more accurately than others, and thus have a tighter focus. (Ideally, a dish should be a section of a parabola.) I was amazed a PSB's comment that, with some dishes, he can get a stronger signal by flexing them to permanently change their shape. That's proof that these dishes are stamped or molded into a less than ideal shape at the factory. That's either poor design or poor workmanship.

As for my dish allignment, I think it's good. I get a good signal from satellites on the west end, the middle and the east end of the arc. Tipping the dish up or down slightly at any satellite position only serves to decrease the signal.

My sg2100 motor's movements are too coarse. In other words, just one momentary press on the remote control moves the dish more than it should. Because of this, I can't fine tune the position of the dish to my satisfaction.

I kind of wish I still had a Ku LNB on my 10ft BUD...to see if the BUD's resolving power would keep channels on adjacent sats from being picked up on blindscans.

Anyway, I thank all you guys for trying to help me with this problem.

 

[PSB]

"I was amazed a PSB's comment that, with some dishes, he can get a stronger signal by flexing them to permanently change their shape. That's proof that these dishes are stamped or molded into a less than ideal shape at the factory. That's either poor design or poor workmanship"

A lot of time its the extreme temperature changes in this part of the world, but on my travels the biggest problem with dishes warping is that the four bolts that hold the dish reflector to the mount have been OVER tightened (Having started out as a mechanical engineer in HEAVY engineering I have been guilty of this also)

Hand tight then half a turn with a wrench is more than enough!

 

[7720driver]

Yeah, I bet there's a lot of people who overtighten, PSB. It gets hot as hell here in Mississippi in the summertime. That might warp some models of dishes that don't have enough frame around the edges. I wonder which type of dish is more prone to warpage.....stamped metal dishes or molded dishes made from plastic or fiberglass, etc.

 

[Tron]

Most cross-satellite interference I get is when scanning a FSS satellite when there is a high-powered DBS satellite next door. An example is when I scan Satmex 5 at 116.8w and get a load of Dish scrambled channels from their adjacent 119w DBS monster. I seldom (if ever) get scannable FSS signals from an adjacent FSS satellite though.

 

[MikeI]

it screws with the signal...look at 11720 on G10. That should be the same signal as 11800 but due to Dish 121 having a signal at 11724 Vertical it overpowers the signal on 11720 (G10). 11800 doesnt have that issue because Dish 121 has a H tranponder at 11800

Last year we had the same issue with North Dakota hockey. They were on G3 but the transponder they were on there was a stronger one on either IA6 or IA5 (I cant remember) that made people with 30" dishes get squat for signal. You needed a bigger dish.

G3 Tr 18 Horizontal - 12041 MHz

 

[Mr Tony]

yep. That was the feed