HX 50 dish pointing - HELP

Most likely the Horizon meter is not programmed correctly for W3A and your polarisation and your LNB local oscillator frequency.  You could try to get an updated file for the Horizon meter, but the file MUST have been made by someone who knows the polarisation you are using and the LNB local oscillator frequency you are using and details of an existing satellite TV carrier within the range of your LNB local oscillator frequency.

On W1 the meter had correct programming to find a known TV carrier on W1 satellite and the programming matched the polarisation and the local oscillator frequency you were using.

The Horizon will always act as a sensitive power meter and help you peak up on any satellite.

If you get a distinctive peak on a satellite (but no lock) then change over to the HX modem and see it that locks up.  The HX modem, like the Horizon, first needs a frequency and symbol rate configured for the wanted carrier.  The Modem will lock to the wanted carrier. 

Best regards, Eric.

If you tell me the frequency and symbol rate of your downlink carrier and the name of the downlink polarisation I will check it here on the spectrum analyser.

Best regards, Eric.

Amended 2 Feb 2008 1134G

If you are trying to receive Horizontal polarisation name...

You have assembled your feed so that the LNB is away from the feed arm.  With the feed arm at the bottom this is the starting position for Horizontal receive polarisation.

(note that fat lump on the horn throat must always be directly towards the feed arm under all circumstances).

Now apply the +48 deg adjustment; rotate the dish by an amount of +48 deg clockwise, as viewed with you behind the dish and facing forwards towards the satellite.  

Your wanted carrier definitely exists. I can see it clearly with a 80cm dish.

using my on line satellite spectrum analyser You need to email me for help to see Horizontal as the default is Vertical. There is a 2 MHz error in my LNB LO freq during this cold weather.

The 13 Msps wide carrier has frequency 1127.2 + 9750 = 10877.2 MHz on Vertical name downlink polarisation. You need an LNB with local oscillator 9750 MHz (e.g. switchable type but not switched up to 10600 MHz)

For elevation this might help

For 33.5 deg elevation set the distance to 26.5 cm.  There are errors here if the central bolt is not yet tightened down. So try up a bit.  

The proper way (see below) is to put an inclinometer against the side of polarisation scale. This circular plate is at right angles to the beam, regardless of polarisation rotation.  

Note this is in Afghanistan with an elevation angle of 48 deg set accurately.

References:
Setting elevation angle Prodelin 1.2m HX dish using tape measure
How to make an inclinometer

Best regards, Eric.

(Amended by Eric 2 Feb 2009 1142G)

With LNB away from the feed arm and the feed arm at the bottom that is true Horizontal.

Polarisation is the direction of the dipole antenna pin inside the LNB input waveguide. If the broad faces are on on either side that is horizontal polarisation, like so:
Horizontal =

It does not matter which side is the pin, either way the electric field is horizontal.

You then apply your +48 clockwise adjustment, starting from a correct name start position.

Horizontal name polarisation with +45 deg clockwise adjustment applied.

Best regards, Eric.

Sir,

Just checking if you have recieved the updated file from my colleagues and if you need further assistance.

James - Bentley Walker

soundtek86 wrote
Quote:


Two warning notes:  Power OFF at the mains wall switch before interfering with the BUC and LNB coax cables. Leave the low voltage mutiway power connector between the power module and the modem plugged in at all times.

I don't think symptom above is related to dish pointing or polarisation.  Check your BUC is actually connected.    The centre pin of the F coax should stick out 1.5mm beyond the rim of the plug.   Maybe your lat long coordinates are in error or maybe some other config entry is wrong.  

Peak up the dish to best pointing ( 89 ) and the polarisation to 48 deg to 50 deg.  

Peaking up means getting the pointing to the maximum digit value ( 89 in this case ).  There is no 'good enough' value above which you can stop work.  It is getting it to the exact centre that counts.

It is not easy.  In elevation, winding the nut down to say 80 on each side and then halfing the count of the nut flats can get you to the middle, in elevation.  In azimuth, move the two nuts apart by 2 turns and then repeatedly gently rest the dish each way in turn against the nuts till the same low value is seen on either side. Then wind both nuts in by same number of turns and flats.
 
The transmit beam is narrower then the receive beam so, in this instance while 83 might be a perfectly good receive quality, the narrow transmit beam may still be too far off.  

Check that your lat long and config parameters are exactly as told.  Then talk to Bentley Walker, check your lat long with them and and they can control your terminal from the hub end.  They may ask you to make some commands etc and possibly adjust the polarisation by 1 or 2 degrees.

Best regards, Eric.

Hi,

it sounds like you are on the right track and the issue you are experiencing is more than likely cable/shorting issue. Please do not hesitate to contact us if you don't make any progress.

James - Bentley Walker.