RE: [amsat-bb] Right-sizing a sat [was: Antennas on the bird]

[Tony Langdon <tlangdon@xxxxxxxxxxxxxxxxxx>]

> The next item would be what kind of transponders. I would 
> think the following would
> be a good choice:
> 
>     1.    mode A

Always a good beginners mode.  Most hams have either a HF rig or a SW
receiver for the downlink.  2m transceivers are pretty common as well.

>     2.    mode JA  (v/u)

At that altitude, another good standby.

>     3.    mode JS    (v/s)

I would prefer U/S or L/S myself, though Doppler starts to get a bit
trickier, if you don't run computer control (something I won't be running
for a while (hmm, should I invest in a laptop and a FT817? :) ).

Or perhaps one of Phil's digital voice birds.  It would be good to try these
modes out.  And the mode descriptor suggests this mode might be a bit
'trippy'.  mode L/S-D perhaps? ;-)

> My reasoning is that 2 meter and 70 cm allmode radios are 
> very abundant along with
> 10 meter rigs, and 2.4 ghz receiver converts are becoming the 
> same with an IF of 144
> Mhz.

Agreed, this would also suit Pacific island countries, where 70cm is rare or
nonexistent.

> Mode "A" would cover more of the 3rd world countries and 
> entry level in the states
> and for the rest of us that have mode "B" & "JA"  would be a 
> walk in the park. And
> mode V/S for those who want new technology...

V/S might work OK on a bird this low.  U/S might be interesting, with very
compact antennas, and the requirements for L/S would be very compact indeed,
especially if one is running an AO-40 class station.

> Also I want to make it clear to all who reads this that I 
> think AO-40 is super and
> can't wait to use it and support the efforts of those who put 
> it there.....But their
> is room for other birds of less complexity and more of them....

Agreed.  I can't wait for AO-40 either, and lookm forward to L/S.  Also
looking forward to being able to talk to most of the people on here directly
via AO-40, something that will be possible for me for the first time (when I
get off my behind and start building :) ).

I have a feeling AO-40 will be an excellent bird. :)
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