ABC 99.0W 4120H30000

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johnnynobody

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Aug 2, 2009
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42N 103W
When looking at it with my handy-dandy XR-3, this transponder alternates between 10.3 C/N and zero every few seconds. Anyone know why I can't good a good lock on this transponder? I checked feed centering and AZ/EL yesterday. Aside from being slightly off-track (adjusted), everything looks fine. I don't have this problem with any other transponders on this and other satellites.
 

Martyn

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Sep 25, 2005
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Concord, CA
The error correction on the ABC channels is quite low, just 9/10 I think from memory. That means if there are any glitches, any interference or the signal falls just a little the receiver has a very small margin before it loses signal.

The FEC number is very important when you're trying to pull in a channel as a larger number (1/2 or 2/3) has much more margin before signal is lost. I think NHK World on 58W is FEC 1/2 and as a result you can pull it in with a small dish.

On ABC, the feeds are meant for broadcasters with much bigger dishes so things get dicey on a smaller dish. It's a clever way to stop too many people from viewing the broadcast without encrypting and a more efficient use of bandwidth.

In your case, it seems your reception is right on the edge and every few seconds your receiver loses its lock.
 
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Titanium

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10.3 C/N is below the minimum to reliably lock onto the 9/10 FEC 8psk mux. More likely that this FEC provides adequate threshold for the link budget. Wouldn't think that it is done an attempt to prevent reception... :confused:

These two links are very helpful in determining the minimum CNR (Carrier to Noise Ratio) to lock a transponder with each format and FEC.

DVBS2: www.satbroadcasts.com/news,81,Minimum_carrier_to_noise_ratio_values_CNR,_CN_for_DVB_S2_system.html

DVBS: www.satbroadcasts.com/news,79,Minimum_carrier_to_noise_ratio_values_CNR,_CN_for_DVB_S_system.html
 

johnnynobody

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Aug 2, 2009
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Thanks for the link -good info - bookmarked. Maybe the dish got warped or a panel or 2 is damaged in a way that I can't seem to see. If so, it'll be awhile before I get another 12 footer even though I believe that there's a "low cost" 12 footer available - Tek or Tech something or other. I guess I'll have to get by without ABC off satellite. I haven't seen any unused 12 footers around here and the 10 footers I've seen have hail damage.
 

wvman

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10.3 C/N is below the minimum to reliably lock onto the 9/10 FEC 8psk mux. More likely that this FEC provides adequate threshold for the link budget. Wouldn't think that it is done an attempt to prevent reception... :confused:

These two links are very helpful in determining the minimum CNR (Carrier to Noise Ratio) to lock a transponder with each format and FEC.

DVBS2: www.satbroadcasts.com/news,81,Minimum_carrier_to_noise_ratio_values_CNR,_CN_for_DVB_S2_system.html

DVBS: www.satbroadcasts.com/news,79,Minimum_carrier_to_noise_ratio_values_CNR,_CN_for_DVB_S_system.html
Since the LAFF MUX went digital, the video on Grit and LAFF wants to stop and start every couple minutes, and at times Grit is unwatchable. Never did that when it was SD, but the signal level is lower on these channels than it was running SD. I rolled one of my 10 footers over to Galaxy 19 and the problem went away. They're going to force me to retire my 7 1/2 dish yet. :)
 

wvman

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Sep 19, 2014
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Thanks for the link -good info - bookmarked. Maybe the dish got warped or a panel or 2 is damaged in a way that I can't seem to see. If so, it'll be awhile before I get another 12 footer even though I believe that there's a "low cost" 12 footer available - Tek or Tech something or other. I guess I'll have to get by without ABC off satellite. I haven't seen any unused 12 footers around here and the 10 footers I've seen have hail damage.
I just located a 10 foot, perferated steel dish. Other than a little surface rust on the reflector, it's in pristine condition. I couldn't find a sticker telling who made it, but it's a very well made dish. It has 8 support arms, I think, on the back holding the dish to the mount. I'm going to stop and take pictures of it this week and post them to see if anyone in here can identify it.

Not sure if I'm going to be able to talk the guy out of it because he doesn't live in the house and I spoke with his renter. I'll be it weighs a ton. I'm not sure what thickness the steel is, but it's pretty beefy. Maybe the renter will know something this week when I stop. :biggrin
 
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johnnynobody

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Aug 2, 2009
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42N 103W
I guess I'll need to look into buying a dish that can do 32APSK+. Even my newest 12 footer can't pull in 16APSK-5/6. I see that TEK2000 has a 13.5 footer. I don't think the city would balk at that but ya never know. A 6 meter dish would be a "problem" though. But, in order to put in a bigger dish I'd have to pour a new concrete pad. Anyway, I hope that the next dish I buy is easier to align and can consistently track the arc. My KTI-12 pulls in the 8PSK-9/10 signals but it has been impossible to get it to consistently park in the correct position without having to actuator-pan the dish back into position. My Paraclipse Classic 12 footer won't pull in 8PSK-9/10 though.
 

bpalone

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Apr 1, 2014
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44N 105W
johnynobody,

I know we are not the far apart, at least by our part of the world standards. My 10 footer is getting the ABC mux on 99W with a Q of 84 to 85 on my Amiko A3. I think they upped the power a tad here over the last month or so, as about 81 was the best I would see before that.

Sounds like either something has moved or possibly you might have some corrosion in a connector. That, or you might of had a tree get big enough to be an issue. Just my $0.02 worth of input.
 
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