radio astronomy

Ian Molton spyro at armlinux.org
Sun Jun 16 15:15:24 PDT 2002


On Sun, 16 Jun 2002 17:45:39 +0100
Chris Lingard <chris at stockwith.co.uk> wrote:

> 
> > Perhaps we should start RAFS (radio astronomy from scratch) ?
> 
> That dish would work on any frequency, just change the tuning
> thing in the pickup.

Well, the DISH should - its just a parabolic piece of metal ;-)

however, at lower frequencies, the field of view is awful.

at 10GHz on my 22" dish, I should get about a 3.5 degree field of view.

at 1GHz, thats a /35/ degree fov.

with an 8 foot dish, I could get <1 degree field of view.

Also, I think the Local Oscillator in an LNB is usually fixed frequency.

I have discovered that the polarisation of my LNB is selected by
applying either 13 or 15V supply for Horizontal or Vertical. also,
apparently many LNBs select two bands depending on the prescence (or
abscense) of a 22kHz signal on the LNB.

>  You could use it as a satellite dish, and send
> downloads.

:-)
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