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Re: AO-40 status report by DJ4ZC



Jon, I know you just love to argue for its own sake, so I know I
*really* shouldn't get suckered into this. But I'll make just this
one comment.

>Wasn't it you who wanted to do away with 70cm and 2m all together?  I could
>find your quote on that......

If you look real hard, you'll find my link budget showing how with
error control coding enabled, the RUDAK 70cm downlink can support a
reliable 67 kb/s from apogee to a simple patch antenna lying flat on
the ground.  That's a pretty major advance over anything that's been
ever possible with amateur satellites and simple unsteered ground
antennas. It should entice many more hams into satellites, which I
assume is our shared goal.

You'll also see that my analysis showed that if you're constrained to
unsteered ground antennas, no other band works as well as 70cm.  As an
interesting aside, the US military has for some time relied heavily on
UHF for mobile satellite communications.

>The fact is that S-band works and works well according to the control team.
>So for those who have two meter reception problems, S band is certainly a
>good option and one that you certainly favor.

That's certainly true; once you allow steerable ground antennas,
S-band emerges as the clear winner over both 2m and 70cm. It's just
that this raises the newcomer's barrier somewhat compared to an omni
antenna on 70cm, that's all.

For those with limited room for antennas and/or who don't already have
a big 2m array, S-band should indeed give much better results than 2m
at a lower total system cost.

Phil

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