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Re: Communications thru P5-A



Wow!  6m  ...I have a 4.9m dish that I promised to a friend for 1296
eme....he decided not to do that, so not sure of its status til I talk with
him.

Eddie, both Kuhne "db6nt" and Downeast Microwave have Rx downconverters for
10.451 GHz which I understnd to be the P5A downlink freq. (someone correct
me if wrong).  They also carry low noise preamps.  For US hams, Downeast is
probably less expensive...not sure of imported cost to Europe.  But you
probably are already familiar with the above sources.

I will eventually get the DEM 10451/144 conv. because it is the eme freq.
in Japan.  Elsewhere eme is on 10368.  Not sure if I will end up putting up
the 4.9m dish, and if it will work at 10 GHz (its a TVRO dish - 4 GHz).
But I have a 2.4m ku-band dish which according to the amsat-dl P5A page is
sufficient to hear it!  Who knows?

73, Ed - AL7EB


At 11:22 PM 8/28/02 +0200, Eddy Jespers wrote:
>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
>>
>> ----
>> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>>
>
>----
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