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RE: [sarex] Shuttle Lands






>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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