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Re: [amsat-bb] RE: Shuttle Lands






>From: "Robert Oler" <cvn65vf94@msn.com>
>To: jstone@sofnet.com
>CC: amsat-bb@AMSAT.Org
>Subject: [amsat-bb] RE: [sarex] Shuttle Lands
>Date: Fri, 23 Feb 2001 13:21:53 -0600
>
>
>
>
>>From: "John Stone" <jstone@sofnet.com>
>>Reply-To: <jstone@sofnet.com>
>>To: <sarex@AMSAT.Org>
>>Subject: RE: [sarex] Shuttle Lands
>>Date: Fri, 23 Feb 2001 06:57:48 -0600
>>
>>
>>
>> > -----Original Message-----
>> > From: owner-SAREX@AMSAT.Org [mailto:owner-SAREX@AMSAT.Org]On Behalf Of
>> > MCGWIER ROBERT
>> > Sent: Thursday, February 22, 2001 7:42 PM
>> > To: sarex@AMSAT.Org
>> > Subject: Re: [sarex] Shuttle Lands
>> >
>> >
>> > Has nothing to do with bulk, weight, etc.  It is
>> > a question of:  will it blow up and kill the
>> > astronauts and destroy the shuttle and if not,
>> > who is willing to stick their neck out and say so?
>> > Will it generate EMI that causes the computers
>> > on board to malfunction?  Are you willing to
>> > risk several billion dollars worth of hardware
>> > and the very expensive lives of people on
>> > just grabbing an HT and sending it up without
>> > tons of certifications and testing?
>> >>I would say that that's the main reason ... and for the same reason 
>>that
>>if
>>I were a pilot of a 747 I wouldn't want a passenger to using his HT in the
>>back. The ILS is just below two meters and I don't know the quality of his
>>equipment ... the last thing in the wold I want is some RFI to screw up 
>>the
>>glide slope reception!!
>>
>>NASA probably goes overboard in testing  ... but ....
>>
>>John
>>K0UWT
>
>Welll...I fly and test airplanes (fighters/transport category airplanes) 
>for
>a living as does my wife..if you ride on an airline whose hq is in Atlanta
>GA and get on a 757 look for the tall blonde in the left seat...her old job
>use to be flying Tomcats.
>
>The shuttle requirements are overstated by several factors. But lets start
>with the airlines.
>
>The most sensitve "reciever" on the airplane in terms of HT's is probably
>the ILS. The system is made up of two recievers...a localizer component (in
>the VHF band) and a glideslope component (in the UHF band).  Having said
>that the transmitter that probably gives RF designers the worst nightmare 
>is
>the DME transmitter (higher frequency but more power and pulse) and the SRS
>beacon...the ATC transponder and now of course the TCAS variants of that.
>If a localizer reciever with an antenna on the outside of the plane (and
>shielded like no tomorrow on the inside) is able to handle those products
>then it will likley handle your (or my) little HT UNLESS of course its
>producing a serious spur on that particular frequency.  If you think about
>the relationship of the ILS localizer to the FM broadcast band and to two
>meters you can see why those recievers are quite robust.
>
>I have an old Narco Mark 12A that I keep in the ham shack for sentimental
>reasons that will under the right set of circumstances nicely recieve a
>nearby FM broadcast station...
>
>Why computers are turned off below 10000 feet has more to do with having
>very large unsecured objects in people's laps during an environment where
>"dynamic" manuevering is possible.  There have been "some" but really
>insignificant (really small) incidences where laptops have been alleged to
>cause interference with the VHF navigation system but so far there is never
>one where they can say "yeap this did it".
>
>NASA well goes overboard really in the requirements that they have...unless
>of course its something that they need on board for a mission and then all
>of a sudden they can "waive" those requirements pretty fast.  The shuttle
>orbiter is one of the most well built from an EMP standpoint vehicle in the
>world because it flies in one of the highest EMP enviroments around.
>
>The point here is that really SAREX and the station variant of that to NASA
>is one of those PR things its not really something that has to do with
>hamming.  Strows get internal points in the astronaut office for making
>school contacts...they are great PR and internal points are important
>because the strows want more missions.  they dont get the same points for
>general ham contacts.
>
>Thats why Bill Shepard is making school contacts.  They are on the time
>line. And the timeline is inviolate.
>
>Robert Oler WB5MZO
>(Clear Lake City Houston...near the JSC)
>
>
>
>
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>
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