[amsat-bb] Re: AO-16 report
lcfowler at magma.ca
Fri Jan 25 08:41:35 PST 2008
Some more observations.
----- Original Message -----
From: "OZ1MY" <oz1my at privat.dk>
> I do not know about other areas of the World - but here
> over Europe the background noise on the downlink is very high.
> Did not experience the normal FM quieting effect by increasing the
> uplink power. I do not understand that - any ideas ?
> Is AO-16 making the noise itself ??
Yes the noise is coming from AO-16 and is readily observed on
my home brew spectrum display unit.
Its amplitude (QSB) varies at a cyclical rate of about 14 seconds
which corresponds to a spin rate of close to 4 rpm.
The peak to min on my FT-847 can be up to 6 S units depending
on elevation distance and angle with the maximum difference
occurring at higher elevations.
> The polarity of the downlink antenna is difficult to make out.
> I thought it is RHCP - but Mark says LHCP.
> For me on the passes to the East RHCP is best !
> Passes from the South - LHCP is best !
> That is a general observation - some times it helped to switch
> during the passes.
> AO-16 might be tumbling a lot ?
My observations agree with this as the sat approaches and
recedes. However during the middle of a high elevation pass
when one polarity is at a minimum the opposite polarity is at a
maximum. I have 2 x 10 turn helix ants on RH and a single
10 turn helix on LH with coax relay switching.
> Have fun and thanks to the team and the builders.
> 73 OZ1MY
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