changing longitude

I have a Technomate 6800 satellite receiver.
The problem I have is my longitude is -0.1636, but  I have to set my longitude to at least 1.2 east.
I cannot receive satellites with a good signal at my correct longitude.
I alsoo cannot receive any satellites west of Hotbird at 13 east.
If I try Hotbird at my correct longitude the signal is weak,at 1.2 east it comes in strong.
I used to be able to get satellites upto 5 degrees west.
There are no obstacles blocking the path of the signal.
Could my dish be out of alignment?
I would be grateful for any suggestions to try and rectify things.

It's difficult to say without knowing your latitude, but it could be as simple matter of magnetic deviation.

//greg//

Just one thought.  Can your dish see low down in the sky towards the south west or is there an obstruction ?

It is likely that your dish is misaligned slightly.

This diagram shows a view of the sky, facing south. The red line and red dots represent satellites. The vertical red line is exactly due south of your longitude and this should be the directlion your dish is pointing when the motor is centralised.

The green line shows the probable path of your dish.  Two things are wrong. Your centre position is slightly to the right (west), maybe 1 or 2 deg off. The overall width of your curve is also too wide, this means the polar axis is slightly wrong.

Before contemplating and  making any adjustments note that setting up a polar mount is highly skilled job.  You only need to make a small random change and you may find yourself spending several days getting back to the starting position, if at all.  Be warned !!.

Your dish pointing angles are here: https://www.satsig.net/maps/satellite-tv-dish-pointing-uk-ireland.htm

Ideally you need to align your dish, initially using accurate scale measurements, and then by pointing to the satellite nearest to your own longitude to peak up your pointing with the motor almost centralised. Getting the whole mechanism accurately aligned to due south is difficult.

The nearest satellite you mention is Hotbird at 13 east (which is rather far away for this purpose).  Line up on 13E exactly using the motor.  Can you now read or measure the sideways angle movement of the motor ?  It should read 14.5 deg.  If it does not read 14.5 deg you need to drive the motor until it does read 14.5 deg exactly. You will no longer be pointed at Hotbird 13 east.  Now loosen the mount on the pole (or otherwise rotate the pole) and turn the entire mount and antenna manually till Hotbird at 13 east is again pointed accurately.  This procedure should set your antenna pointed exactly south when the motor is driven back to the central position.

The above is only one step in the alignment process.  If you have any doubts about making adjustments do call a local satellite TV installer with polar mount expertise, to help you.  It is remarkably easy to mess it up and never get it right.

There are two further settings, the main motor axis angle (53.6) and the small downwards tilt (-6.9) of the dish. These two angles combined make up the  beam elevation angle for an imaginary satellite which due south of you.
wxw
Best regards, Eric.

Just for the record, magnetic deviation in your location - the error induced in a compass by local magnetic field - is currently estimated at roughly "1.67 west"  (see https://www.ngdc.noaa.gov/geomagmodels/struts/calcDeclination ). So even though a calculation may produce an azimuth of ~163.7 degrees to HB13 for example, a compass would actually read ~165.4 degrees when pointing at the same spot. And magnetic deviation for any given location changes over time.  So - in addition to Eric's advice -  it wouldn't hurt to determine if the dish controller needs to be provided with  your current magnetic deviation to optimize pointing accuracy.

//greg//

Thank you for your advice and the photo showing the correct position of my satellite dish.
It is most appreciated and I can now receive satellites upto 5 degrees west.