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RE: Communications thru P5-A



for me, and the people i know, cost is a problem, but not the whole problem
:).

space is. living in a flat, im very lucky i tricked the local council into
allowing me to put up a "satellite dish" for tv :), and thats 60cm.

as i said in a previous email, i would love to see p5a fly and work well,
its just what sort of dish size would be needed.

i automaticly assume that 60cm will be no where near enough.

thats my basic problem :).

anyways, i wasnt on the board when ao40 was being planned (if the board was
up at the time) and i wonder if the same things were talked about when the
list of freq's were announced?

Speak to you later.

Scott Elliott
M3SJE / 2E1FJB / M1SJE

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Eddy Jespers
Sent: 28 August 2002 22:22
To: amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] Communications thru P5-A


We still have plenty of time, to prepare ourselves for the P5-A.
At his moment, i am building a 6 m antenna, which i got for free.
( had to take it away, cost... ? 100 $ ? )

To get an accurate readout of the position, i got 2 incremental
encoders, for free.

I am building controller for the motors and the encoders, cost will be
around 150 $

Need some low noise 10 GHz pre-amps, can be build for little money,
or can be purchased, price around 200 $ .

Need some down converters, receiver, modem ... should not cost me more
than 400 $.

I am sure my complete set-up will not be more than 1.000 $ ! to be ready
for P5A.

Hams complaining  are spending multiple $ to buy a HF amplifier, or a HF
rig...

So, what is the point, i thought ham radio was being experimenting with RF.
I can not understand how anybody can be against a P5A project, we have
to support this ! If we can achieve this mission, and can take part of it,
we should
be proud of our hobby!

73's Eddy ON7UN





----- Original Message -----
From: "Grant Zehr" <grant@dzehr.com>
To: <amsat-bb@AMSAT.Org>
Sent: Wednesday, August 28, 2002 5:11 AM
Subject: [amsat-bb] Communications thru P5-A


> It might be pertinent to the discussion to see what NASA used going to
Mars
> in 1965.  I checked my copy of NASA SP-130  (p. 11) "A Review of the
Mariner
> IV Results".  NASA used a 10 watt transmitter on board the spacecraft
> "broadcasting continuously at 2300 megacycles".  Antenna was a "high gain
> elliptical 4 foot antenna" (p.4).  Spacecraft was 3 axis stabilized with
its
> antenna pointed towards earth.
>
> To establish a reliable data transfer the data rate was initially set at
33
> 1/2 bits per second, but before arriving at Mars the rate was slowed to 8
> 1/3 bits per second.  (BITS...not Kilobits or Megabits!)  At the receive
> end, LARGE (!) antennas were used.
>
> I'm not an engineer, but I'm having trouble seeing how the P5 thing is
> really going to work.  If anyone asked, I'd rather see the resources go
> toward building another "AO-13", a "Fuji" in just a little higher orbit,
or
> a truly operational "AO-40" with the correct orbit and working
transponders.
> One of those would get me excited!
>
> Grant Zehr AA9LC
>
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> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

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