L-Band at Ceduna
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From: <Brett.Reid_at_email.protected>
Date: Mon, 18 Jun 2007 03:32:56 +1000
Hi,
Aidan and I have installed a test reflector (1.5m offset satellite dish)
at the vertex of the 30m dish and an L band receiver from Hobart. We
aligned the dish optically so that the ray from the center of the feed
goes to the center of the offset dish and on to the center of the
subreflector. We checked the alignment at 12 GHz using the Optus D1
satellite and the small K band feed used for satellite TV. We were
pleased with a beam width and alignment demonstrated with this test.We
then changed over to the L-band feed. The first scans were pleasing with
a system temperature obtained of around 1000 Jy. No further alignment
has been done. We know that a larger dish will collect more of the
signal. The vertex tube is 2m internal diameter and our experimental
1.5m reflector does not fill this.
The 2 channel plot that Aidan performed is attached. The 2 channels are
linears. The frequency is 1400 MHz, The bandwidth is 64MHz. We intend to
try linear to circular conversion through the quadrature hybrid in the
morning once we have wound a test helix.
Both the L-band feed and extra reflector should be easily removed for
other frequency use.
Pictures are to come.
Regards,
Brett and Aidan
Received on 2007-06-18 03:34:32
Date: Mon, 18 Jun 2007 03:32:56 +1000
Hi,
Aidan and I have installed a test reflector (1.5m offset satellite dish)
at the vertex of the 30m dish and an L band receiver from Hobart. We
aligned the dish optically so that the ray from the center of the feed
goes to the center of the offset dish and on to the center of the
subreflector. We checked the alignment at 12 GHz using the Optus D1
satellite and the small K band feed used for satellite TV. We were
pleased with a beam width and alignment demonstrated with this test.We
then changed over to the L-band feed. The first scans were pleasing with
a system temperature obtained of around 1000 Jy. No further alignment
has been done. We know that a larger dish will collect more of the
signal. The vertex tube is 2m internal diameter and our experimental
1.5m reflector does not fill this.
The 2 channel plot that Aidan performed is attached. The 2 channels are
linears. The frequency is 1400 MHz, The bandwidth is 64MHz. We intend to
try linear to circular conversion through the quadrature hybrid in the
morning once we have wound a test helix.
Both the L-band feed and extra reflector should be easily removed for
other frequency use.
Pictures are to come.
Regards,
Brett and Aidan
-- Brett Reid Observatory Manager, Radio Telescopes University of Tasmania School of Mathematics and Physics phone + 61 3 6248 5285 email brett.reid_at_utas.<!--nospam-->edu.au web http://www-ra.phys.utas.edu.au/~breid/ <div> <img src="../../att-0787/Lscan.jpg" alt="Lscan.jpg" />
- application/octet-stream attachment: Lscan.jpg
