Different FEC means non-stable picture on one mux??

[Mr Tony]

Quick question.

I'm trying to figure out why on my 6 foot dish the Nets on G4/G16 can stay stable at 30 quality (right now they're around 65-70), yet the Equity mux on G3 is breaking up even at a 60 quality on the Pansat 1500 (threshold is normally 30 or so)

I noticed the FEC (Forward Error Correction) on the Nets is 3/4 whereas Equity is at 7/8. I know when I had the C-Band in front of the garage, the quality on Equity was 75 and very stable

Is it the higher the FEC (I'm assuming 7/8 is higher than 3/4) the reason I cannot get a stable picture on Equity stuff and how does this FEC work?

 

[voomvoom]

Tony, I'm not going to pretend I know what I'm talking about, but my guess would be, the 6'er is twice what you need to capture G10 ku reliably, however the 6'er is about 2/3rds what you need to capture G3 C-band reliably. Just my guess? Remember, I don't have a true clue!

Al

 

[Mr Tony]

It just seems odd that I cannot get a stable picture on G3 Equity even at a 60 quality on the Pansat but a 70 is stable. I even get bleedover form IA5/G25/T5 with the TCT Church stuff

The PR Nets on G4 I can get stable with a 30 quality. I'm going to try and jack the dish up a few inches and see if that helps.

 

[voomvoom]

Maybe the interference from IA5 is causing the problem? Because it's a small dish for C-band? It won't hurt to jack the dish up, I'd try anything to get it to work right.
I just looked at IA5 and IA6, and assuming that 4040 TP being vertical on them while it's horizontal on G3, it's probably not coming from those. But, it looks like on IA6, CBS uses both 4020 and 4060, which are horizontal, so the interference might be coming from them. While IA5 doesn't seem to use those horizontal 4020 or 4060 TP's much. My guess would be the interference is coming from IA6. Like I said before, I don't know what I'm talking about. Just making a wild assumption?

Al

 

[Anole]

Who knows what the quality means on any given receiver.
Why aren't they all calibrated to be within 10 or 20% of each other?
I've got a USB receiver that must have less than a dozen discrete quality levels.
What's with that?


Without looking it up, I thought 3/4 meant three data bits and an error correction bit, while 7/8 meant seven data bits and one error correction bit.
In other words, more data in 7/8, but more susceptible to problems.
Someone please slap me if this isn't quite correct.

So, given two crappy signals with errors, the 3/4 would look better than the 7/8

However, if the adjacent-bird interference is possible, then it may well be the answer.
See about getting somebody with a similar receiver and a 10-foot dish to run the same test.

Or, get someone with some proper test equipment to come over and read the signal out of your LNB and supply the definitive answer!

 

[ftarock]

FEC has nothing to do with signal quality/strength.
In plain English version, if the FEC is 1/2, it means that half of the bandwidth is used for FEC, the other half is used for program content.
The more bit used for FEC, the less work for the receiver to do in terms of correcting the errors.
In this case, FEC of the Nets os 1/4 while the Equity is 1/8. That's why the receiver works harder when you tune to the Equity. Even you get 60 quality for the Nets, it does not mean you get clean lock on the signal.
In this case, less bits used for FEC makes the receiver works hard, up to a point it can't make any more correction, you get break up picture.
Getting a larger dish will help to get cleaner signal, that helps the receiver when processing the tight FEC mux.
Good luck

Quick question.

I'm trying to figure out why on my 6 foot dish the Nets on G4/G16 can stay stable at 30 quality (right now they're around 65-70), yet the Equity mux on G3 is breaking up even at a 60 quality on the Pansat 1500 (threshold is normally 30 or so)

I noticed the FEC (Forward Error Correction) on the Nets is 3/4 whereas Equity is at 7/8. I know when I had the C-Band in front of the garage, the quality on Equity was 75 and very stable

Is it the higher the FEC (I'm assuming 7/8 is higher than 3/4) the reason I cannot get a stable picture on Equity stuff and how does this FEC work?

 

[jself1982]

Ice...

My 10 foot mesh brings in a fluctuating 75-80-85% on the G3 channels and 97-100% on the G4 channels. Even in a good storm my G3 doesn't fall below 65-70% range. However if I nudge the dish e/w on G3, I instantly lose the Equity channels, whereas, on G4 I can nudge the dish about 3-5 steps in either direction before it starts pixelating. And that's here in upstate SC. Hope this is some kinda help to you.

 

[truckracer]

I have a perfectly tuned sami 7.5' mesh c/ku polar mount dish
I cannot most days lock the equity mux on G3C c-band.

I can perfectly lock the other feeds there and all other sats.

My pansat 2500 does a little better with just occasional macroblocking, but my fortec ultra does not lock very well at all and it shows 85 quality.

It's definitely an FEC thing.

I am guessing I would need a 10-12 foot dish to get a clean lock.

 

[Mr Tony]

Ice...

My 10 foot mesh brings in a fluctuating 75-80-85% on the G3 channels and 97-100% on the G4 channels. Even in a good storm my G3 doesn't fall below 65-70% range. However if I nudge the dish e/w on G3, I instantly lose the Equity channels, whereas, on G4 I can nudge the dish about 3-5 steps in either direction before it starts pixelating. And that's here in upstate SC. Hope this is some kinda help to you.

same here. I literally have to be nuts on to get a semi-stable picture. At 60 quality it starts to stabalize.

It won't hurt to jack the dish up, I'd try anything to get it to work right.

working on that right now

 

[Mr Tony]

Who knows what the quality means on any given receiver.
Why aren't they all calibrated to be within 10 or 20% of each other?
I've got a USB receiver that must have less than a dozen discrete quality levels.
What's with that?

I know on the Pansat 1500 the threshold 99% of the time is 30.

Without looking it up, I thought 3/4 meant three data bits and an error correction bit, while 7/8 meant seven data bits and one error correction bit.
In other words, more data in 7/8, but more susceptible to problems.
Someone please slap me if this isn't quite correct.

So, given two crappy signals with errors, the 3/4 would look better than the 7/8

Thats kinda what I was thinking

 

[Mr Tony]

FEC has nothing to do with signal quality/strength.

That part I figured out

In plain English version, if the FEC is 1/2, it means that half of the bandwidth is used for FEC, the other half is used for program content.
The more bit used for FEC, the less work for the receiver to do in terms of correcting the errors.
In this case, FEC of the Nets os 1/4 while the Equity is 1/8. That's why the receiver works harder when you tune to the Equity. Even you get 60 quality for the Nets, it does not mean you get clean lock on the signal.
In this case, less bits used for FEC makes the receiver works hard, up to a point it can't make any more correction, you get break up picture.
Getting a larger dish will help to get cleaner signal, that helps the receiver when processing the tight FEC mux.
Good luck

Thanks for the clean explanation. Unfortunatelly, a bigger dish is not an option unless I move

I'm going to try and jack the dish up a few more inches. I know on the deck the very bottom of the dish doesnt clear the house but if I jack it up, it should

 

[Mr Tony]

oh well...jacked it up to 28" off the ground (from 21") and still cant keep a stable picture on G3 Equity

although I did get the HD channel on AnikF2
(couldnt get it before)

MOved back to G4 for a rock solid 76 on the Nets

 

[dfergie]

My Dvbworld box does really good on the Nets, better PQ than the Coolsat does and thats watching at 70" from my Mits...

 

[dem0nlord]

This is the same reason so many have trouble with HBO on G1, the 7/8 FEC. Yes, bigger dish is the only real fix.

 

[somery]

wish i could figure out what size to call my dish. it doesn't fall even on any number or half number.
its almost 10 foot if you go with the curve of the dish,
its 105.5 inches if you don't count the flange (8 foot 9.5 or something like that and not 8 and a half)
and two inches over of 9 foot straight across and count the curveback flange around the dish


if off a little here and there, because its hard to hold the tape and guesstimate where i measure on the curved outter rim

 

[Mr Tony]

I found a way to get the quality to go up on the Equity stuff.....and it was done on a fluke

I was swapping LNB's out and had G4 locked in. Forgot to tighten the screws on the scaler ring to hold the LNB in and as I was moving to G3 the dish wouldn't move (I hacve to ghetto move it). So I jolted the dish a little bit and the all of a sudden the quality jumped to 75 (from 60)

Looked at the LNB and it had slid in farther towards the dish. Normally I have it on the 38 line of the rings (which works for almost everything) but this was on 32 and it worked. Couple other feeds dropped a smidge but we'll fix that

This is all weird as when the dish was in front of the garage I had it on the 38 line and had 75 quality...so maybe there is a smidge of the dish being blocked when its on the deck.

But hey it works

 

[gabshere]

thats weird but you know these things are often found out by accident. its weird kinda like that thing i had with the pbs channels ... check those and see if it makes a difference on those .....for some reason they are different..... i won't say oddball just act differently....

 

[tvropro]

I have a 12 foot dish and a Pansat 2700A. I get the Equity mux with a level of 86 and a quality from 72 to 77, it is stable 99.9% of the time. In very windy weather I can get slight breakup here and there. We may be getting adjacent satellite interference on that transponder. I know my 12 foot is really good at 2 degree spacing. The Equity mux on G3/C seems alot more sensitive than anything else I receive on FTA. With a 7/8 FEC it's giving us a better quality picture but less error correction, Just like HBO on G-15 on the 4DTV. So all factors dish, alignment, etc have to be maxed out.

 

[tvropro]

I found a way to get the quality to go up on the Equity stuff.....and it was done on a fluke

I was swapping LNB's out and had G4 locked in. Forgot to tighten the screws on the scaler ring to hold the LNB in and as I was moving to G3 the dish wouldn't move (I hacve to ghetto move it). So I jolted the dish a little bit and the all of a sudden the quality jumped to 75 (from 60)

Looked at the LNB and it had slid in farther towards the dish. Normally I have it on the 38 line of the rings (which works for almost everything) but this was on 32 and it worked. Couple other feeds dropped a smidge but we'll fix that

This is all weird as when the dish was in front of the garage I had it on the 38 line and had 75 quality...so maybe there is a smidge of the dish being blocked when its on the deck.

But hey it works

By moving the feedhorn in closer to the dish you are causing the dish to under illuminate. This will give you less gain from the dish but will also cut down on your sidelobes. Also cutting down on adjacent satellite interference.

 

[truckracer]

I get a perfect lock on HbO/max digitals on G1 with my 7.5' sami mesh,
But equity on G3 is broken up pretty bad even with 80 quality.