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· Godfather
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306 Posts
Discussion Starter · #1 ·
We all know that the new KA signals fall faster than KU signals when the weather turns bad. Here in south west Florida its nearly every day that we get rain storms that knock out the signal (atleast on the HD channels coming from the KA birds). Most of the time when this happens SD programming is still ok. For instance right now I'm recieving between 76 and 86 on all transponders from 101, but 0's across the board from 103c with the exception of 2 transponders in the 20's. (before anyone asks, yes I get upper 90's on clear day from all the orbital locations)

So my suggestion is why not replace the "More Info" button on the seaching for satellite signal tab to "check SD channel availablity" or just have the reciever automatically try tuning the SD channel when the KA signal is not found and then present a message similar to the one that pops up when your watching a HD channel and the reciever is set to 480i. This would prevent having to go through the menu to turn on "show SD duplicates" every time it rains, which is something I couldn't see my dear old parents trying to figure out.

Since Directv is firmly committed to KA technology this issue is something I see hurting them in the long run if not addressed. Of course I perfer HD, but I'll take SD over nothing when its storming outside.

Anyone else's thoughts?
 

· Mentor
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49 Posts
I don't completely understand the science of it, but I now all my tv's are hd. With the multi sat dish, i would much rather insure my hd signals are optimized. I too have rain fade rather quickly on the HD channels, with no affect on the SD channels. I remember back to the old single LNB dish, and with the bigger multi sat dish, rain fade is almost not existent on the SD channels.
Dave in NJ
 

· Godfather
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306 Posts
Discussion Starter · #4 ·
While I think you missed my suggestion, it sounds like you'd benefit from it.

davidpoe said:
I don't completely understand the science of it, but I now all my tv's are hd. With the multi sat dish, i would much rather insure my hd signals are optimized.
The design of the AT9 and AU9 (sidecar and slimline) dishes is such that when 101 and 119 are optimized, so are the 99 and 103 Ka locations. conversly if your"HD signals are optimized" so are you SD signals.

davidpoe said:
I too have rain fade rather quickly on the HD channels, with no affect on the SD channels.
Because of this you either have to:
A) have "show SD duplicate" enabled, which makes navigating the guide cumbersome, or
B) enable and disable "show SD duplicates" each time it rains,if you want to watch TV, even if it is in SD instead of the perferred HD.

davidpoe said:
I remember back to the old single LNB dish, and with the bigger multi sat dish, rain fade is almost not existent on the SD channels.
Absolutly! Which is why I say the inability to EASILY tune to the SD version could hurt Directv in the future. Before rainfade was an occasional occurance, since the KA era it is becoming more and more bothersome to the point where I can see people leaving for cable to avoid it (or complaining to friends who avoid the service because of it)
 

· Godfather
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Discussion Starter · #5 ·
ansky said:
I understand your idea, but in order for Directv to implement something like that they would have to acknowledge that rain fade is a problem, which I don't think they ever do.
I know, I was waiting for someone else to say that because I see that as the biggest hurdle to overcome. :nono:
 

· Geek til I die
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9,822 Posts
Someone (hey Winegard, Channel M.aster) would sell LOTs of dishes if they came out with a larger version of the new 99/101/103 dish, with about 3db more gain than Directv's.... I'm going to experiment with a 36" and a 6' dish if the temperature would ever drop below 100...
 

· Legend
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That would be the 1.2m Alaska/Hawaii dish, and the whole package is available here for $460 plus shipping.

I am considering doing this myself. You need the dish itself, the 99/101/103 LNB kit, and the mount (which is on a different page on the site).
 

· Registered
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Davenlr said:
Someone (hey Winegard, Channel M.aster) would sell LOTs of dishes if they came out with a larger version of the new 99/101/103 dish, with about 3db more gain than Directv's.... I'm going to experiment with a 36" and a 6' dish if the temperature would ever drop below 100...
3db will buy you nothing in a rain fade situation. The large dishes are great when you have a weak signal but you would need much more than 3db to have any meaningful impact on rain fade.
 

· Hall Of Fame
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OTA

No rain-fade, all sub-channels, 24/7/365.
 

· Legend
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texasbrit said:
3db will buy you nothing in a rain fade situation. The large dishes are great when you have a weak signal but you would need much more than 3db to have any meaningful impact on rain fade.
I think Doctor J said 10 dB in another thread (was it the "Trees!" thread?), but I haven't seen actual gain specs published on the antennas. There might be a way to approximate it based on shape and size, but that's well beyond this caveman engineer.

Edit: To answer a couple of other posts, I still get rain fade OTA because I'm 53 miles away from the towers, and I don't remember seeing any cataclysmic "black" radar-level summer T-storms the last time I was in Seattle! (They happen daily here.) :) The AT-9 is pretty good through normal and even heavy rainfall--hits the crapper when "dark red" or worse comes to town.
 

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litzdog911 said:
I almost never have rain fade problems with either my AT9 or AU9 dishes. And I live in Seattle! :)
Seattle gets frequent rain, but generally not the heavy thunderstorms that are common on the east coast and midwest. That's what causes the rain fade. I don't have any problems during "normal" rain storms.
 

· Legend
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I'm pretty new to DirecTV and just assumed that I lost ALL stations when it rains hard and I get the "searching for satellite" message....

Since I'm usually watching HD, I might actually be able to watch the sister SD channel?????
 

· Icon
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d max82 said:
We all know that the new KA signals fall faster than KU signals when the weather turns bad.
Who is the 'we' (?). Not this engineer, with over 35+ years of microwave experience, and at least 25+ years of both experimental and operational experience with Ka (and virtually all the other bands) satellite signals.

Since the beginning of Spaceway1, followed of course by Spaceway2 then DirecTV10, I've found that the Ka signals (both spot beam AND national beam) are at an RF and bit redundancy (forward error correction) level, with current receiver sub-systems, that EXCEEDS that of the Ku/DBS transmission system that's been in place for well over 14 years.

This has been verified by simple measurement at my antenna farm, using (in the case of the DirecTV Ku/DBS and Ka signals) a first generation AT9 (Sidecar) AND a 'second gen' AU9 (Slimline) dish, both during weather related 'events' (including major snowfall), and by utilizing typical RF absorption techniques within the free space between the dish antenna and the satellite transmission (better known as 'screening' the signal). In doing this, the received signal can be lowered right to the threshold point, in a controlled manner.

The Ka signals maintain signal integrity (no dropouts, no 'pixelization') while the Ku signals are well below threshold, if not at zero.

This idea of the Ka being worse than the Ku/DBS is simply.... an urban myth.

Certainly, IF the Ka signal was transmitted at exactly the same RF power level, with exactly the same receive electronics (both LNB's and receiver specifications), with exactly the same forward-error-correction, you'd be right.

But it isn't. And 'on the ground' testing proves that time and again.
 

· Legend
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spray the dish in some Rain X, or Pam cooking oil. This will cause the rain water to sheet off faster and will reduce signal infraction
 

· Registered
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philherz said:
I'm pretty new to DirecTV and just assumed that I lost ALL stations when it rains hard and I get the "searching for satellite" message....

Since I'm usually watching HD, I might actually be able to watch the sister SD channel?????
Correct, the SD channels come via a different technology than the new (and soon to be all) HD channels.

IcedOmega13 said:
spray the dish in some Rain X, or Pam cooking oil. This will cause the rain water to sheet off faster and will reduce signal infraction
Most of the time when I get rain fade it is actually in the distance as it is the high level clouds blocking the signal, not anything right near/on the dish. But in some cases that can help.
 

· Cool Member
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I had rain fade on the new HD channels more so than the old mpeg2 HD channels and the tech found out I had an old multiswitch and he changed out to a high band width multi switch. Now I have 95 on about every transponder on 99 101 103 110 and 119. I haven't been thru a big rain storm yet but they look solid. I don't know if that info helps but just trying to help.

milt
 
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