Post by Admin1 on Mar 4th, 2021 at 2:12pm
Prodelin C band polariser for sale, for use in 1.8m or 2.4m antennas.
Location: Ipaja ,Lagos state Nigeria. If interested email me eric@satsig.net ref: 20:12 03-03-2021 and I will forward your email to the seller.
When inserted between the OMT and the feed horn the C band polariser changes linear polarisation to circular polarisation.
The multiple external curved ribs at one end is simply where the external clamp fits.
Brief spec: 3.7 to 4.2 GHz RX and 5.925-6.425 GHz TX. Cross-pol isolation is 17 dB RX and 19 dB TX.
Read more here: Prodelin C band polariser specification and dimension drawings. (.pdf)
Assembly:
The OMT has the LNB and BUC attached with the LNB waveguide sticking out sideways. When the OMT is assembled to the polariser the plane of the RX waveguide needs to be at 45 deg to one of the flat surfaces of the polariser.
There are internal vanes/slots along the opposite faces inside the polariser. Mark these opposite faces on the outside with felt tip pen or paint so you know where they are. There are two alternative +/- 45 deg possibilities. One will produce RHCP TX / LHCP RX and the other will produce LHCP TX / RHCP RX. Use this picture below as a guide:
The figure above shows the polarisation as it emerges from the feed horn. If you have a single reflector antenna then the polarisation changes at the reflector so what goes to the satellite is the opposite.
One way will work perfectly and you will receive the wanted signals. The other way and you will receive any signals on the opposite polarisation. No polarisation adjustment angle is needed. If you get it wrong, don't worry, undo the joint and turn the polariser 90 deg. It is a good idea not to insert all the bolts and nuts till you have it working correctly.
Read more on my page: Setting up circular polarisation
Location: Ipaja ,Lagos state Nigeria. If interested email me eric@satsig.net ref: 20:12 03-03-2021 and I will forward your email to the seller.
When inserted between the OMT and the feed horn the C band polariser changes linear polarisation to circular polarisation.
The multiple external curved ribs at one end is simply where the external clamp fits.
Brief spec: 3.7 to 4.2 GHz RX and 5.925-6.425 GHz TX. Cross-pol isolation is 17 dB RX and 19 dB TX.
Read more here: Prodelin C band polariser specification and dimension drawings. (.pdf)
Assembly:
The OMT has the LNB and BUC attached with the LNB waveguide sticking out sideways. When the OMT is assembled to the polariser the plane of the RX waveguide needs to be at 45 deg to one of the flat surfaces of the polariser.
There are internal vanes/slots along the opposite faces inside the polariser. Mark these opposite faces on the outside with felt tip pen or paint so you know where they are. There are two alternative +/- 45 deg possibilities. One will produce RHCP TX / LHCP RX and the other will produce LHCP TX / RHCP RX. Use this picture below as a guide:
The figure above shows the polarisation as it emerges from the feed horn. If you have a single reflector antenna then the polarisation changes at the reflector so what goes to the satellite is the opposite.
One way will work perfectly and you will receive the wanted signals. The other way and you will receive any signals on the opposite polarisation. No polarisation adjustment angle is needed. If you get it wrong, don't worry, undo the joint and turn the polariser 90 deg. It is a good idea not to insert all the bolts and nuts till you have it working correctly.
Read more on my page: Setting up circular polarisation