SuperDISH Rainfade

[Scott Greczkowski]

I have received a report from one of my contacts who lives in the tri state area that their SuperDISH did very well in yesterdays downpours (there were tornado warnings!)

I am told that the 105 FSS signal held up well durring the very heavy rain while the DBS signals were bouncing all over the place.

This is some good news in my book, I was worried that rainfade on the SuperDISH would be bad.

 

[Guest]

I guess, FSS certainly has its advantages.

 

[Stargazer]

This confirms what I have said about the lower power satellites, that they are less suspeptable to rainfade. The DBS signals would go out before the FSS signals would (unless you have a poor signal from the FSS satellite on a clear day).

What kind of signal did he get on a clear day compared to when it was downpouring? What signal do you have to get from the FSS satellite to get a signal lock and what is the highest signal you can get from the FSS satellite?

 

[Fat Tony]

it's all due to the relative wave size. lower frequency = larger waves.0

 

[new_hd_fan]

(scratching his head remembering the theory of antenna and system design from his former career)

This confirms what I have said about the lower power satellites, that they are less suspeptable to rainfade.

If rain attenuates a signal by (let's just say for argument sake) 5dB that amount of attenuation will be the same regardless of power level. A high power signal will attenuate the same amount as a low power signal. In fact the relative difference in power level will remain the same between the two signals.

it's all due to the relative wave size. lower frequency = larger waves.0

You might have a valid argument here but from what I understand, the frequencies of DBS and FSS are as follows:

Downlink: FSS: 11.700-12.200 GHz
DBS: 12.200-12.700 GHz

The difference in frequency between these two bands is so small as to be almost imperceptable. I would also point out that while the rain fade in the FSS band will be slightly less, the gain of the reflector will also be slightly less in the FSS band wiping out the benefit.

The only explanation is that the total system gain for the FSS LNB is better overall than the DBS LNB. This could be caused by the fact that on SuperDish, the DBS Antenna/LNB feeds are off center from the reflector, but I would have expected this to be accounted for. I suspect the real answer is that since "retail" FSS service is such a new animal the FSS Antenna/LNB feed was somewhat overdesigned to avoid disappointment in the marketplace. This is certainly good news.

 

[mike123abc]

Guess the question is if the DBS signals were going out before the FSS were all on the superdish. Or were they comparing SuperDish to Dish500. One would expect the SuperDish DBS LNBs to have a much better signal since the dish is so much larger compared to the Dish500. The DBS system is designed for a 18-24" dish, on a big 36" dish it should do better.

 

[Scott Greczkowski]

From what I understand the contact was checking his signals for 110/ 119 and 105 on his SuperDISH, not two seperate Dishs.

 

[James Long]

From what I understand the contact was checking his signals for 110/ 119 and 105 on his SuperDISH, not two seperate Dishs.

He has a real SuperDISH?

JL

 

[Scott Greczkowski]

Yup

 

[James Long]

Wow. The DSS LNB's must really be off focus in the new design.

JL

 

[JohnH]

Could be the Polarity has something to do with it.

DBS = Circular
FSS = Linear

 

[Scott Greczkowski]

I just talked to my contact again he said he never lost picture on his SuperDISH on 110 or 119 just watched the signal levels go up and down greatly during the storm.

He will try to call me later with signal readings from all 3 satellites and transpnders.

 

[md_paul]

 

[wcswett]

I just talked to my contact again he said he never lost picture on his SuperDISH on 110 or 119 just watched the signal levels go up and down greatly during the storm.

Now that's good news!

--- WCS