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Re: Right-sizing a sat [was: Antennas on the bird]



In one of the replies is was said that the belt started around 1800 miles up.  With
harden components a sat should be able to survive pretty good at 1600 to 1700 miles
up which should give a pretty good foot print and some where around 45 to 60 minutes
of talk time..

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

    1.    mode A

    2.    mode JA  (v/u)

    3.    mode JS    (v/s)


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.

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...

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....

    guy lemke
    kd6mtu



Jon Ogden wrote:

> I could be wrong on the altitude of the belts.  I was trying to find out
> what the exact altitudes are, but could not.  2500 miles may be too low.  I
> know they've been mentioned on the bb before, but I just couldn't remember
> the exact height.  So don't quote me on it!
>
> 73,
>
> Jon
> NA9D
>
> on 1/14/01 11:16 PM, guy lemke at guy@com-pair.net wrote:
>
> > That may be true I don't know what the Alt. of the belt is but the concept is
> > good
> > even if the Alt. that I suggested is bad...
> >
> > Jon Ogden wrote:
> >
> >> on 1/14/01 11:07 AM, guy lemke at guy@com-pair.net wrote:
> >>
> >>> I agree with the smaller birds... with an Alt. of some where around 1500 to
> >>> 2500 miles...A polar orbit with 4 birds spaced out over a 3 or 4 hours space
> >>> would give really good coverage... I have a internet domain
> >>> "WWW.HAMSATS.ORG"
> >>> that I have not done any thing with yet but would be willing to donate it
> >>> towards a team (hopefully including myself) in
> >>> putting together these birds and getting them up....
> >>
> >> I believe that the 1500 to 2500 mile range you suggest is smack dab in the
> >> middle of the Van Allen Radiation Belt.  Nothing survives there for very
> >> long.
>
> -------------------------------------
> Jon Ogden
> NA9D (ex: KE9NA)
>
> Member:  ARRL, AMSAT, DXCC, NRA
>
> http://www.qsl.net/ke9na
>
> "A life lived in fear is a life half lived."

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