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rain fade question

nanda
08-14-2005, 02:49 PM
Hi,

Does anyone know if RAIN FADE effects HIGH DEFINITION reception more so than regular Direct TV reception? It seems it would because I heard that High Definition requires much more data to transmit the picture.

Thanks
Nick

RSawdey
08-15-2005, 12:19 PM
I'd think both would be affected similarly...

GRN
08-15-2005, 02:17 PM
When I have rain fade, it affects a specific satellite. Since none of my HD channels are on that satellite, nothing happens to them. There have been times when there have been monsoon conditions and I still get my trusty HD channels.

Whether the channel is SD or HD has nothing to do with it.

leww37334
08-16-2005, 06:46 AM
If the question is changed to: Is a triple LNB dish effected more than a single LNB dish then I believe the answer is yes. I have had both up during rain (why is a long story) and the triple LNB woud lose signal where the old single LNB did not. I realize this is not rigorous, but I think it could be demonsrated.

high5in
08-16-2005, 09:46 AM
I had a case lately where for a half hour, my DirectTV was useless during a nasty Tstorm. But my Zenith Silver Sensor indoor antenna going up 2 stories on a 50' cable had spotless HD from a good 25 miles away from the TV station's antenna.

rbinck
08-16-2005, 12:46 PM
The ellipitical dish is slightly worse than an 18" round dish on all three LNBs. The offset is the High Definition receivers are generally better with low signal levels, so there is somewhat a wash. I use 30" round dishes myself and have very little rain fade.

6201jim
08-16-2005, 12:49 PM
Hi,

Does anyone know if RAIN FADE effects HIGH DEFINITION reception more so than regular Direct TV reception? It seems it would because I heard that High Definition requires much more data to transmit the picture.

Thanks
Nick

Rain fade should not affect HD more than SD except for two caveats:

One - An SD channel which carries local station programming (and perhaps an HD channel with local station programming) is using a spot beam which appears to deliver a higher power downlink signal. As a result, I sometimes find a national SD channel will get lost in a rain fade but a local station SD channel will not. The same behaviour may occur with HD (it will depend on the specifics of the satellite design).

Two - If you are picking up an HD signal OTA from a local station you are using the UHF band (200-400 MHz) which is much less vulnerable to rain fades that a satellite downlink that works at 12 GHZ. I live in Wash. DC and have never experienced a rain fade on an OTA channel.
This is a good reason for using OTA reception for HD rather than D*where it is available.

As another member pointed out above, a triple feed antenna probably has slightly less gain than a single or dual feed dish, but this difference should not be a 2nd order effect.

ovredcoat
08-16-2005, 02:49 PM
RBINCK.............that 30 inch dish.......are you using it with the triple LNB on Directv?! I am interested in anything that will help with the rain fade.

RSawdey
08-17-2005, 01:04 PM
The 30" SuperDish only uses on LNB... you need 3 of them to cover all sats...

rbinck
08-17-2005, 03:54 PM
Like RSawdey said it takes three dishes to cover all three satellites. The eliptical dish is a morphing of three parabolic reflectors into a single dish, that is why it is oblong. Obviously there is not a complete parabolic reflector for any of the three LNBs as the left of the dish will only be able to reflect about half as much as if it were round, for example, as the rest of the left hand area of the dish will reflect to the center. Same for the right hand LNB. For the center LNB, only the top and bottom of the dish is reflecting the signal to the center LNB. That is why even though the dish is larger than a single round 18" dish, the signal gain is less.

I'm not using Super Dishes, just standard 30" round dishes for Directv. The SuperDish is used for Dish Network for multiple satellites, so don't run out and buy one for Directv. See: http://www.dishplace.com/product_info.php/products_id/65605?osCsid=6ca44b2acec854440dfe9be626eb467b for SuperDish

Alternately some people use the Channel Master Gain Master DBS dish.
See: http://www.channelmaster.com/home.htm

I don't think the Gain Master is as good as multiple 30" (or 35" even) round dishes, but the cabling is much easier.