[amsat-bb] Re: Redundant geostaionary birds?

[Dave hartzell]

It looks like the commonly adopted block conversion for C-band
transponders wouldn't land in our bands.  There seems to be a delta
for 2.2 GHz for the block conversion (e.g. 5.9 GHz up, 3.7 GHz down).
We'd need more like a 4 GHz conversion to land in our S-band, given a
5.8 GHz uplink.  I'm sure the filters aren't quite tuned to go below
out of band, either.

Another issue I just realized is that these transponders use polarized
signals (left, right, vertical, horizontal, polka-dotted)....this
again makes using an old communications sat a bit more difficult (but
not impossible) for us hams.

Looks like this was not meant to be!

73,

Dave
NøTGD


On 1/28/07, Karl Bullock <karl at bullock.org> wrote:
>
> Dave hartzell wrote:
> > 3) Most of the uplink freq's are in the 5.9 GHz range (out of our
> > allocation) and downlink in the 3.7 GHz range, again, (out of our
> > allocation).
> >
> That may be _the_ problem.  I don't know the current capabilities of
> these birds, and if they have any capability of either "retuning" to a
> close amateur band, or if there are other assets on board, but inability
> to transmit/receive on one of our bands would probably make this a non
> sequitur.  Those with more intimate knowledge of current flying
> technology would need to speak to this.