RE: [sarex] Mir to be eclipsed?

[A Thomas <70374.440@xxxxxxxxxxxxxx>]

Hi jamie

For 11 GHz I am using what you would call a TVRO receiver. This is
essentially an 80 cm offset dish with a low noise ku band LNB. I don't know
if it's the same in the States but here in the UK satellite domestic TV is
ku-band. My receiver is made by Scientific Atlanta. It is a domestic/light
industrial set, but for this purpose, it has an AGC output. So, as the rx
detects an emitter, the voltage rises. And as the sun transits across the
beam, the voltage rises and then falls. So what you do is find the area of
the sky that the sun is about to move in (Checking that the azimuth and
elevation are not Ku band TV satellites) and wait for the sun to transit
the beam. (If it doesn't transit it's not the sun!) Takes a bit of
practice.

This wasn't really my idea, if you do a web search for "radiosky" you will
find a site of the same name that has some interesting books.

One of them also describes a simple integrator, R and C, R about 10 k ohm I
think and C say 5 microfarad, and this is suitable to directly connect into
a chart recorder.

It works!!!

So I shall be tracking the sun. the beamwidth is about 2 degrees so I have
about a "pass" of 20 minutes. I will be looking for two things:

1  During the eclipse, when the moon occults the emitting part of the sun,
the AGC voltage should very suddenly drop to its resting voltage

2 as the LNB has  a fixed polarity, if there are polarity changes on the
emission (due to what I beleive is called the faraday effect on the
atmosphere) then there will be a sine wave superimposed on the agc voltage.

At some point I will also look for Ku band reflection from a full
moon......

Note that this isn't anything like eme sensitivity; however it does detect
solar transits.



I hope this will interest you

andy G0SFJ
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