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Re: ISS and ECHO



Hello Pat,

>It would be easier and cheaper to > raise the power to 2 watts than for 
>hundreds
>or thousands of amateurs to buy beams and preamps.

It is not quite that simple.  The satellite must maintain a minimum 
voltage/current level using the battery system.
With the current operating software, once the transmit levels are set by a 
command station, they remain at that level until the command station resets 
it.  This could be 10-12 hours.  It has been found that leaving the 
satellite at high power levels for long periods compromises the battery 
voltage/current levels.  It is a very exacting dance to manage the satellite 
power usage, transmit power level, and solar cell power generation.

The command stations understand the desire for higher power operation.  They 
have have been working diligently to come up with ways to make the power 
generation vs usage more efficient. The command stations do this as a hobby, 
they have jobs and families to attend to as well.  They volunteer a great 
deal of their time to monitor, analyze and command the satellite for our 
enjoyment. AO-51 has only been in orbit about 7 months, we don't even know 
how it reacts during a full orbit around the sun yet.

I understand that there is an upgrade in the works that will allow higher 
power levels when the satellite has it available (i.e. generating power from 
sunlight) and switch to lower levels when not generating power.

This obviously must be well tested on the ground and then uploaded and 
tested on the satellite.

Satellite operation is interesting, challenging and offers and excellent 
learning experience, which is why many of us enjoy it.

There are many other modes that AO-51 does that offer an opportunity to 
experiment with new modes and operation. I encourage you to try some of 
these during the Wednesday Experimenters' Day.  Even setting up small yagis 
on a tripod and configuring that to track the satellite is a good exercise 
and will greatly improve your operating  experience.

73,
Gould
WA4SXM

----- Original Message ----- 
From: "McGrane" <tmcgrane@suffolk.lib.ny.us>
To: "Amsat BB" <amsat-bb@amsat.org>
Sent: Friday, January 28, 2005 12:52 PM
Subject: [amsat-bb] ISS and ECHO


> Greetings from Patrick N2OEQ 32323
>
> This is a response to e-mails from andrew and emily
>
> I have a good station; for ECHO , I purchased yaesu ft-8800r dual band rig
> with a great reciever, utilizing diamond 500 vertical on 50 foot of 9914
> which hears better on high angle passes. I joined amsat for 39.00, bought
> echo book for 15.00 and donated 40.00 towards fund for echo. Maybe not
> much but it was what I could afford. It would be easier and cheaper to
> raise the power to 2 watts than for hundreds or thousands of amateurs to
> buy beams and preamps. A lesson can be learned from commercial satellite
> tellite telephone equipment and practice.
> The ISS has been operating packet for years with sporadic activity from
> the crew. For a couple of weeks last fall, the crew configured the kenwood
> radio for cross band repeat and many people made quite a few contacts
> which included some contacts with the crew who were listening in.
> I personally believe the ultimate satellite contact is to have a QSO with
> an astronaut. I personnaly prefer talking to someone rather than digital
> be it packet or email.
>
> Thanks again for the post and dont take it personally, thanks for your
> responses.
>
> 73, pat
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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----
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