Universal LNB compatibility with different Horn

The mode matched feed horn (with the 505) is designed to form part of an offset feed designa antenna system. The feed horn and its adaptor tube should be regarded as a fixed part of the antenna, always oriented so the 505 is away from the feed support arm. The asymmetric feed horn cancels out the cross-pol of the offset dish geometry and the result is near perfect cross-pol performance.

The Hughes Universal LNB/OMT (P/N 1501882-0002) may be used with any antenna.  It is unusual in that the LNB and OMT are integrated together. There is one rectangular waveguide port, for the transmit direction from the BUC.

If you have a 505 type feed horn you may attach an Universal LNB/OMT at any of the 30 deg positions.  Receive polarisation is the direction of the Universal LNB/OMT F connector.

Best regards, Eric.

From your location the satellites appear in a steeply sloping line going up the sky in the west.
https://www.satsig.net/maps/satellite-dish-pointing-lagos-nigeria.htm
Elevation=40, Azimuth 267 Pol=+81 deg

Once you have found any satellite note that the adjacent ones will be higher up and slightly left or downwards and slightly right.  Note and mark the position of a found satellite and progress from there to the next satellite.

The Hughes signal measurement system works in two ranges. 0-29 and 30-100

Each time you pass a satellite you will get readings in the range 0-29.  29 is a very powerful satellite signal. Find satellites and get familar with moving from one to the next.

If you have an elevation scale on the bracket behind the dish try to find a satellite that results in a reading of 40 deg elevation.  If you can do this then you have likely found the correct satellite, even if the reading won't go higher then 29.

If you have no elevation scale, find out the offset angle of the dish from the dish installation manual. (e.g. 23 deg).  Set the front face of the dish vertical and the beam elevation is then 23 deg.  You want a beam elevation = 40 deg, so tilt the top of the dish backwards by an amount of 17 deg.  An inclinometer held against a plank of wood up across the front will help you measure this amount of movement.  https://www.satsig.net/pointing/how-to-make-inclinometer.htm

If the Hughes screen measurement won't go above 29 it is due to some problem: wrong polarisation, wrong 22kHz tone, wrong tuning, wrong symbol rate, wrong SBC.cfg file, wrong LNB type in the pull down menu. When all these things are right the receive LED will light up and you should peak up, typically to 91 or thereabouts.

Your meter works similarly to the Hughes modem.  The meter gives some basic power reading on any and all satellites but will only display "SATELLITE FOUND" if the polarisation is correct, if the meter tuning is correct and if the LNB 22kHz tone control is correct. The meter is typically programmed to look for a suitable TV carrier on the wanted satellite, in the same polarisation and same part of Ku band as your wanted satellite internet carrier.

Your polarisation adjustment is 81 deg clockwise, as viewed facing forwards towards the satellite in the sky. I would peak up on each promising satellite and then turn the feed 90 deg so as to test both polarisations.

On the Universal LNB, the LNB connector is the direction of receive polarisation.  The connector should stick out in one of these directions:


Note this view is with you facing towards the satellite in the sky with +81 deg clockwise adjustment applied.  The red line is along the orbit equator and is called Horizontal polarisation name.  Only one direction of polarisation (red or black) will work.

The other satellites are up and down the red line !

If you were on the equator the adjustment would be 90 deg and horizontal name polarisation becomes vertical relative to your ground when facing directly west.
wxw
Best regards, Eric.

Eric,
You have been extremely helpful and usefull to me!
Simply put: YOU ARE FANTANSTIC!

I followed the direction provided by you and others in this forum and final got my VSAT up and running. I now have access to the internet!!!

I must say that this website is very rich in terms of resources to help with all aspects of VSAT technology. I consider www.satsig.net the "final bustop" to all VSAT related enquiries.

Please continue the great work and keep the flag flying.

Once again, thanks Eric and co.!