Constellation Networks: Satellite communications dish installations in Africa

Channelmaster 2.4m C-band dish antenna at mountain forest malaria research site near Amani, Tanzania
Channelmaster 2.4m C-band antenna

 The image below shows the C band feed horn, polariser for circular polarisation and two transmit reject filters apparently in series between the side 4 GHz flange on the OMT and the input to the LNB.  A 6 GHz heliax coax cable connects the transmitter output signal to the 6 GHz end port of the OMT.

circular polarization feed
Grease is recommended for the threads of the four stainless steel screws that retain the two little hoop straps  that retain the transmitter to the yokes upside down underneath the arm.  The rotary orientation of the whole feed assembly is of no consequence for circular polarisation. 

Channelmaster 2.4m C-band dish antenna
Channelmaster 2.4m C-band antenna

circular polarisation feed
The transmitter is connected directly to the OMT, thus minimising losses at the 6 GHz frequency.  On receive, the short protective transmit reject filter is in the side arm between the OMT side flange (4GHz) and the input to the LNB.

In both of the above images there are two ways of assembling the polarizer to the OMT.  The unit may transmit RHPC and receive LHCP or vice versa according to two alternative positions of the polarizer and OMT, at 90 deg to each other.

Go to www.constellationetcorp.com web site  for contact details.
Call them or email your details and request a quotation for your particular network application.

The content and images on this page are partly based on information provided by Constellation Networks Corporation and are reproduced with their permission. The images of the dish construction and installations were provided by photographer Dick Elleray, to whom many  thanks. The images are copyright AfriConnect ©  2004 All rights reserved.

RHCP means right handed circular polarisation.
LHPC means left handed circular polarisation.
OMT means ortho-mode tranducer, which splits two orthoganal linear polarisations into two waveguides.
LNB means low noise block downconverter (receives 4GHz band, outputs L band)

This satsig.net web site - navigation link: Satellite networks for Africa by Constellation Networks
Page - Started 18 Nov 2004, last amended 4 March 2007