[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

AO-51 or ECHO downlink power

greetings from Patrick N2OEQ 32323

I am currently recieving ECHO well with a home brew 8 element yagi on 25
feet of 9913 coax into a ft-8800 dual band rig.

I have a few points regarding the low power downlink of ECHO.......

According to what I read, the solar panels produce about 20 watts of power
in full illumination.

The control electronics use about one watt of power.
At maybe 30 percent efficiency, I would guess the two half-watt
transmitters might use about 3 or 4 watts of power.

Considering the need to charge the batteries for eclipse operation, it
seems to me there is some solar power going to waste.

A year and a half ago, I proposed to the group, changeing the satellite
control to allow excess solar power, beyong battery charging, to be
directed to the transmitters for higher power daylight operation.

I have since heard that the power is kept low to reduce the cycling level
of the batteries. Apparently less power means longer battery life.

I do believe in the logic of making the satellite last longer but there is
an expense in that its use is limited to those who invest in equipment
that can be costly.

In the original echo book, it was stated that the transmitters were rated
at 7 watts out and that it would have the power of another old satellite
with a 4 watt downlink. This would enable a person with readilly available
or normally used equipment like a typical home or mobile dual band station
to use the satellite.

I believe one of the intents of echo was to introduce new users to
satellites and amsat. 

If echo had a downlink that was readilly recieved by typical FM stations,
more people would probably try it. As it is now, there are very few new
users with many regulars including myself.

The FM satellites are very popular but the SSB satellites are seriously

Short of proposing a new high power FM satellite, may I suggest that amsat
reevaluate the battery life issue and consider raising the transmitters

In the interim; did anything happen with the software rewrite to use the
excess solar power?

BTW, yes, I am a "can we do this" type of person. Things get done that way
and hopefully it inspires others to new ideas. Look at the big picture.

On another point (if you're still reading) I am exploring the use of a 435
mast mount preamp on a high gain vertical for satellite reception during
dual band use. Does anyone know if the mirage 440 preamp would switch out
with a 145 mhz uplink transmission on the same line????

Thanks for your time and replies.

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org