# LNB Skew on Cassegrain

• I think what pe1chl tried to explain is that you've to tweak to the minimum, because that's where the 'polarization discrimination notch' is maximal.

In other words: listening to a H-beacon (or program), switch the LNB to V and tweak for minimum signal.

Many broadcast satellites have two (different) programs on the same frequencies/transponder but with different polarities (H and V).

Assuming around 25 - 30 dB polarization discrimination for linear polarizations it's possible to obtain clear (DVB-S) pictures with C/N's of around the same magnitude.

• How to use the sun to allign the dish ?

For my qth the satlex calculates 26° East.

So when sun is turning 360° in 24h, that should give 15° travel per hour. So i can point the dish to the sund at 10h and 20 min giving the sat position

Am i right ?

• DN1HRZ sadly no.. the sun is not exactly in the south in Germany at 12h local time. I would advise to get either a real compass (not the smartphone ones) or better to use the Az/El from Satlex, which for you is 163.8°/29.7° and check on Google Maps for a geographic point which is in the correct heading. 29.7 deg should be indicated on any proper sat-dish as elevation so this should give you a start point to optimize from. Good luck and let us know if you run into problems!

• To find your location on Google earth, draw a line with a ruler and drag the endpoint.You can get the Angle relative to the starting point.If the Angle is true north, it is very accurate...

## Images

BG0AUB-Urumqi, xinjiang, China - NN33SV

• My problem is in my garden in direction south i have some high trees. so i need to move around there to find a place without shadow at noon. last weekend i testet with the sunshade foot. but it was in shadow-so no free air to the satelite.

i dont see a problem later when dish is mounted on the roof, but at first i wanted to test at ground zero

• try the smartphone app from https://www.dishpointer.com/

It works fine. You can look "through" the smartphone in direction to the sat.

In this way you can see very well all obstacles towards satellite and look for the best point for the dish.

Robert - DD4YR - JN57QS

Edited 2 times, last by DD4YR ().

• If you can select the frequency , Symbolrate and FEC : yes

Broadband searching does not work ... else you want to search for BADR4 Satellite, its near Es'hail 2.

Robert - DD4YR - JN57QS

• ## DB2OSMar 30th 2019

Moved the thread from forum Hardware to forum LNB for RX.