Bill Ress wrote:
Bob,
I don't think we'll find a device on the current
marketplace that will
suit our efficiency needs. But, if we're willing
to develop (fund) a
program to design and build a Class E, 1 watt,
5.7 GHz amplifier
module, we might get to 70 and maybe 90%
efficiency. I have seen Class E
X Band amplifiers with 60 to 70%. The design,
including the choice of
active device(s) must start with the goal of
being Class E since several
interesting parameters are in play. You just
can't take a Class C
amplifier and "push" it into the switching mode.
Perhaps a Class C
amplifier might be enough.
I am listening and more than willing to consider
anything that gets the
job done with a reasonable budget.
But it's a very interesting design challenge - to
be sure!! When do we
start??
But, lets assume that we build amplifiers with
100% efficiency. 36 or 43
elements still requires 36 to 43 watts input.
What has me concerned is
that the current satellite structure design calls
for 6 solar panels
with, what I guess is about 25 watts per panel.
That appears to be
consistent with the 100 watts power generation
stated in the current
Eagle Functional Requirements.
Are we still working with 100 watts or did I miss
something??
What we are working with is "whatever we can get
away with" so long as
it meets the communications systems goals as stated
in our working
document from the San Diego meeting of last
summer. That is the
system
we want to design and the concept we wish to
support. If this
involves
us working on our own amplifier design, and not
using monolithic designs
from Hittite, etc., so be it. The efficiency translates directly
to
multiple scenario big wins for us. Class E for this is
completely
acceptable.
Regards...Bill - N6GHz
Robert McGwier wrote:
The Hittites were interesting, they had potential, but they
are not
really efficient enough. We will find better
parts.
Bob
73's
Bob
N4HY
--
AMSAT Director and VP Engineering. Member: ARRL,
AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL
SDR WG Chair
"If you're going to be crazy, you have to get paid
for it or
else you're going to be locked up." Hunter S.
Thompson
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