[Moon-net] 2.40m dish

SAM JEWELL jewell at btinternet.com
Fri Sep 26 11:27:07 CEST 2008


Oene, et al

I have a 'large' dish compared with Sven, in that I use a 2.3m KTI TVRO dish. With this I use an OK1DFC septum polariser feed on both 23cm and 13cm. Both of these were kitted by G4HUP. I don't have a choke ring on either feed (yet>>>>)

On 9cm I have used a converted integrated C band LNB with modified Chaparel feed and linear polarisation. I have been amazed at just how easy it is to hear so many stations on each of the three bands with this size of dish. On 23cm I have worked 35 stations with 200w in the shack, about 150W at the feed. Of these 35 about 10 were on JT65 only.

On 13cm I have worked  just two station, but this with a very much sub-optimal feed position, 50W in the shack, but a reasonable LNA (HI!). 
9cm is still receive only.

A few months ago I discovered that I had previously positioned my feeds back beyond the focus by a few cm. I correctedthat and since then I have improved sun noise on both 23 and 13cm by a noticeable amount. Maybe now when I add choke rings they will have a positive benefit and not the effects noticed previously?

Last weekend I resurrected my 13cm system, on receive, and copied around 20 stations in the few hours of moon time I had available (I'm not a night person!). I am currently modifying my polar mount to give more moon time. The new 13cm SSPA is almost ready to go.

The purpose of this posting is to encourage anyone who is thinking of using a small dish to go ahead. Whatever size dish you have, it's never big enough anyway! Small dishes can work well, even on 23cm, and it will get you started....and most important.....thinking about system improvements.

If I did more operating and spent less time building my initial count on 23cm and 13cm would both me much larger, I think!

73 de Sam
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