►
From YouTube: Link Budget Walkthrough by Jan King
Description
A walkthrough of Jan King's Link Budget Spreadsheet. Given to Wally Ritchie and Michelle Thompson for Open Research Institute on 12 May 2021.
Many of us in the amateur satellite community are familiar with Jan King's link budget spreadsheets.
This version incorporates a large amount of new content. The project addressed in this version is Open Research Institute's microwave broadband digital DVB-S2/X transponder work. However, this spreadsheet can be adapted for many different projects.
The current version of this spreadsheet can be downloaded from here:
https://github.com/phase4ground/documents/tree/master/Engineering/Link_Budget/Jan-King-Link-Budgets
Note: This is a long video! This video explains the spreadsheet in detail. There's action items and changes that are discussed in the video that will appear in later versions of the spreadsheet.
For an introduction to the open source amateur satellite system that this link budget is being developed for, please see the introduction to this video presentation.
https://youtu.be/fCmzS6jBhHg
ORI's work is internationally developed and free for all to use. Our mission is to support organizations with advanced digital tools, techniques, and designs.
Learn more about ORI at https://www.openresearch.institute/
Comment and critique about this spreadsheet is welcome and encouraged.
-Michelle W5NYV
A
B
A
C
A
Yeah,
okay,
so
if,
if
you
buy
into
the
fact
that
we
pretty
much
have
to
talk
about
higher
orbits
for
operational
systems,
yeah
leos
could
can
work,
but
even
leos
might
want
to
be
digital,
but
for
an
operational
system
the
way
to
get
the
capacity
up
is
is
to
take
advantage
of
of
the
gain
that
you
can
drive
and,
of
course,
at
the
same
time
that
we're
going
up
in
altitude
on
an
operational
sense
we're
also
going
down
in
spacecraft
size
because
of
cost.
You
know
we're.
A
A
And
the
other
aspect
is
that,
if
you're
using
digital
and
you
use
forward
error
correction
by
going
to
the
double
coder
decoder
world,
like
you
get
with
dvb,
s2
or
s2x,
then
you're
getting
the
required
signal
to
noise
ratio
c
over
n
zero.
Whatever
you
want
to
call
that
parameter,
which
is
signal
and
noise
ratio,
you
require
way
less
signal
noise
ratio
by
about
as
much
as
16
to
18
db
than
you
require.
A
A
All
right,
very
good,
all
right
so
now
to
the
spreadsheet
this.
This
is
an
evolution
of
a
lot
of
different
things
plugged
together
and
a
whole
bunch
of
new
stuff
added
in,
but
I
I
was,
I've
never
actually
used
it
in
a
corporate
environment
where
people
actually
use
this
thing
in
a
configuration
controlled
environment.
A
But
I
set
it
up
to
be
able
to
do
that
so
that
if
you
have
various
engineers
and
over
overviewers
project
managers
or
whatever,
if
they
take
the,
if
they
take
the
box,
then
their
box
turns
green
and
when
finally
there's
some
configuration
control,
dude
who
says:
okay,
we'll
do
it,
then
the
whole
thing
turns
green.
Now
the
idea
is
to
pass
code,
protect
these
these
green
squares,
so
that
so
that
you
can
only
enter
it
in.
A
C
A
That
was
what
the
first
page
is
about,
and
then
the
second
page
follows
up
every
time
you
do
a
revision.
This
is
what
the
revision
tree
looks
like
for
this,
this
document.
So
it's
been
revived.
You
see
it
goes
all
the
way
back
to
august
of
2010
and
some
elements
of
this
actually
go
back
to
about
2001.
A
And
what
I
try
and
do
is
use
colors
in
a
specific
way,
and
I
do
this
on
every
single
spreadsheet
I
do
on
any
subject.
Is
I
make
the
blue,
the
blue
cells,
the
entry
data,
the
the
yellow
cells,
the
results
and,
if
they're,
black
or
blue
blue
means,
I
can
probably
change
it
without
stepping
on
the
formula
black.
A
If
I,
if
I
modify
cell,
it's
just
a
white
cell
with
black
text,
I
kill
the
formula
and
I
might
as
well
start
over
because
the
the
spreadsheet
probably
won't
work
after
that
or
I
won't
be
able
to
change
some
parameter
at
all
once
I've
screwed
that
up.
So
it's
always
a
good
idea
with
my
spreadsheet,
since
I
I
haven't
password
protected
everything
in
them
to
save
a
clean
copy
of
it,
so
you
always
have
a
fresh
copy
in
case
you
step
on
cells,
which
I
do
to
myself
all
the
time.
A
C
A
D
D
A
A
A
I
think
you
and
I
discussed
this,
but
there
was
an
epic
beyond
which,
if
you've
got
a
newer
piece
of
software,
then
it
will
not
recognize
32-bit
words
explicitly.
You
have
to
tell
it
some
piece
of
information
we
haven't
figured
out
yet
so
it
knows
this
is
a
32-bit
piece
of
software,
not
a
64-bit
piece
of
software.
A
A
Okay,
so
the
the
way
you
drive
this
thing
is,
I
put
in
what's
called
a
scenario
planner
which
allows
you
to
make
quick
changes
to
things
you
you
you
want
to
find
out,
and
these
are
all
the
things
in
the
blue
area.
Here
I've
got
two
methods
of
changing
the
antenna
size.
One
is
changed
on
another
sheet,
I'll
show
you
or
I
can,
alternatively,
use
a
another
antenna
here.
So
I
have
two
ways
of
defining
antennas,
specifically
on
the
user
terminal
setup.
A
I
do
it
and
it's
done
there
and
the
other
way
is
to
do
it
here
and
and
the
the
upper
one
assumes
that
the
antenna
size
for
the
uplink
and
the
downlink
antenna
could
be
different,
which
could
easily
happen
in
the
amateur
service.
Whereas
if,
if
you
have
the
command
common
antenna
for
up
and
down
it
assumes,
you
might
have
a
diplex
or
something
in
two
different
feeds
on
the
dish,
so
it
depends
on
which
one
you
use
there.
A
I
select
the
receiver
bandwidth,
but
the
way
I've
got
it
set
right
now,
it's
kind
of
from
some
old
commercial
stuff.
It
gives
you
an
option
of
what
ones
you
can
pick
and
if
you
don't
like
that,
you
have
to
go
over
to
the
this
section
over
here
on
the
right
and
load
in
different
options
and
that
that's
kind
of
clunky
right
now.
So
that's
one
thing
I
don't
like
and
then
so
I've
got
it
set
now
with.
So
I
have
the
receiver.
A
Bandwidth
is
very
narrow
and
the
transmit
bandwidth
is
as
wide
as
it
can
be.
Now
that
means
we're
kind
of
operating.
The
downlink
is
a
combined
combination
of
all
the
uplinks,
so
think
of
the
downlink
as
a
tdma
and
the
uplink
as
an
fdma,
but
it
could
be
an
ffdma
cdma
type
of
link,
but
right
now
I've-
and
I
would
say
this
is
just
until
this
was
socialized,
so
we
could
figure
out
what
we
really
wanted
to
do.
A
So
that
needs
some
more
discussion
than
we
have
time
for
today.
But
I've
assumed
here
that
we
have
a
very
narrowband
uplinking
user
and
there
are
multiple
users.
So
this
is
an
fdma,
a
multi-access
thing,
whereas
on
the
downlink
we're
assuming
every
user
is
receiving
the
same
carrier
with
the
same
modulation
and
the
same
coding
and
the
same
mod
code
step,
and
so
they,
the
channel
sorting
out,
is
done
in
in
tdma
in
that
mode.
So
that's
that's
the
assumption
made
here.
B
A
And,
and
for
the
rain,
we've
turned
off
the
the
rain,
which
really
turns
off
the
cloud
attenuation
and
the
rain
attenuation
in
the
itu
link
model,
not
the
rest
of
the
losses
like
the
atmospheric
losses,
which
are
very
critical
as
well.
So
I
have
what
you
call
the
clear,
clear
sky
condition
in
the
rain
on
condition,
so
we
have
the
rain
it's
asking.
Is
the
rain
turned
on?
C
A
And
then
the
last
point
here
is
that
that
this
loca,
if
I
have
a
green
parameter,
it
means
it's
transferred
from
another
page
and
we're
going
to
talk
about
your
stations
in
a
minute.
But
you'll
you'll
know
that,
for
anything
with
involves
a
lot
of
rain
like
like
24
gigahertz,
does
that
you
will?
It
will
very
much?
The
link
will
very
much
depend
on
where
you're
located,
so
I
made
it
easy
to
be
able
to
swap
link
user
locations,
so
you
could
just
plunk
the
user
in
it.
A
B
A
A
B
A
Yes,
but
just
for
that
for,
for
the
sake
of
this
discussion,
I'm
using
vcm
here,
which
means
the
the
telecommand
operator,
is
keeping
track
of
what
the
status
of
the
loading
of
the
transponder
is,
and
it
changes
the
mod
cut
step
when,
on
average,
for
all
the
users
over
the
whole
earth
that
are
looking
at
this
transponder
and
using
this
transponder,
what
the
average
performance
for
those
users
are,
because
some
users
are
at
low
elevation
angles.
Some
are
at
high
elevation
angles
and
the
difference
in
the
performance.
A
Given
the
how
dynamic
dvb
s2x
is,
you
can
have
a
very
big
range
of
settings
you
could
use
here
and
they
would
work
for
some
users
very
well,
but
they
work
very
poorly
for
other
users.
So
not
sure,
that's
a
whole
discussion
area,
but
what
this
is
is
the
the
results
of
the
uplink.
So
what
this
is
doing
is
summarizing
the
whole
situation
for
the
user
uplink,
it's
the
bandwidth.
A
D
D
B
D
B
A
Yeah
well,
okay,
what
it
would
do
is
it
would
change
the
table.
I'm
going
to
show
you
here
that
that
selects
this,
but
but
as
long
as
there
are
multiple
steps,
then
what
would
be
displayed
here
once
adjusted
would
be
the
what
was
achieved
in
the
link
results.
So
it
says
okay,
this
is
what
I
was
able
to
achieve
for
the
price
of
this
parameter
right
here.
A
This
data
uplink
character,
noise,
power
density
ratio.
Think
of
this
number,
if
you
will-
and
it's
used
in
almost
everybody's
digital
communication
link,
parameter
set,
it's
the
equivalent
of
the
one
hertz
bandwidth
signal
to
noise
ratio.
So
if
I
put
a
carrier
of
this
strength
into
a
w
through
a
one
hertz
filter,
that's
the
signal
and
noise
ratio.
I
get
out
of
that
filter.
A
So
it's
an
easy
way
of
it's.
It's
it's
a
nice
number
that
goes
from
you
know
the
low
20s
to
above
100,
and
it
gives
you
an
indication
of
link
performance,
it's
nice
in
the
way
of
you
mentally
thinking
about
it.
But
in
addition
to
that
you
always
know
that's
the
signal
noise
rush
I
get
if
I
was
putting
that
whole
signal
into
a
single
carrier,
and
I
was
looking
at
it
with
a
one
hertz
filter
on
the
ground,
and
then
it
tells
me,
oh
by
the
way
you've
got
clear.
A
This
is
the
a
effect
achieved
signal
to
noise
ratio,
and
if
you
want
to
talk
about
energy
per
symbol,
to
noise
power
density
ratio,
which
is
another
thing
used
as
a
common
parameter
within
the
dvb
s2
world,
that's
that's
that
computed
version
of
the
signal
to
noise
ratio.
Then
you
have
the
same
thing
for
the
downlink.
But
but
here
you
see
the
bandwidth
is
is
now
up
to
a
megahertz
and
in
a
megahertz.
I
can
actually
get
through
that
thing
at
a.
A
C
D
A
The
uplink
is
separated
from
the
downlink,
so
the
the
uplink,
the
guy
who,
when
he's
either
talking
or
sending
digital
text
or
video
or
whatever
he's
sending
it's
going
to
be
digitized
and
put
into
a
you,
know
a
payload
computer
and
then
that
payload
computer
is
going
to
insert
the
results
of
that
that
old,
guy's
uplink
data
stream
he's
going
to
merge
it
with
the
other
uplink
data
streams
into
a
downlink
stream.
That's
the
assumption.
I'm
making
here.
D
A
A
I
I
realize
there's
going
to
be
all
kinds
of
cool
guise
and
things
going
on
for
people
to
know
what
what's
what
they're
getting
from
the
other
guy,
that
that's
understood,
but
this
is
just
if
we're
looking
at
gross
bits
here
in
the
data
stream
and
what
it's
saying
is
okay,
for
that.
For
this
case
and
we'll
we'll
show
you
where
we
are,
I
think
we're
at
apogee
in
this
right.
At
this
minute
I
can
support
with
dvds2.
A
It
will
support
qpsk
rate,
one
half,
which
is
about
the
third
mod
cod
step
in
the
dvds2x
stack
and
I'm
getting
for
that
910
mega
symbols,
I'm
getting
about
0.9
megabits
per
second
out
of
the
link
and
the
res
the
c
over
n0
that
gave
me
that
was
60.62
and
my
spectral
efficiency,
which
is
kind
of
something
I
like
to
keep
track
of
is.
Is
you
know
about
0.98?
A
A
A
It's
really
cool.
Okay.
Now
I
put
this
new
thing
in
here
because
it's
it's
a
discussion
area.
If
you
assume
that
every
bit
that
goes
up
give
or
take
some
control
bits
is
going
to
have
to
come
back
down,
then
the
downlink
capacity.
My
metric
here
has
been
that
with
a
six-year
spacecraft.
I
wanted
to
be
able
to
tell
the
commission
that
we
could
support
a
minimum
of
a
hundred
voice
grade
communications
conversations,
which
means
200
users.
Minimum
could
be
supported
with
this
asset.
A
B
D
A
What
what
what
we're
gonna
talk
about
now
is
what
happens
when
various
things
happen,
but
what
I
I
can
tell
you
is
I'm
ringing
the
washrag
about
as
hard
as
I
can
for
the
power
I've
got
available
at
the
frequencies
involved
and
for
the
locations
on
the
earth.
Where
I
have
I
I
I've
got.
I've
got
quite
a
this
is
this
is
about
as
far
as
I
can
go,
so
what
what
okay?
A
So,
let's
just
continue,
but
I
put
the
summary
down
here
and
the
main
thing
is
to
see
regardless
of
where
I
am
in
the
orbit
and
the
kind
of
users
I
use.
I'm
always
checking
back
this
parameter
here,
and
this
is
just
a
figure
of
merit
for
me.
It
says
I
want
that
number
to
be
very
close
to
a
hundred,
and
if
I
do
that,
then
I,
as
a
operator
of
a
satellite
system
of
this
kind
of
meeting
my
commitments
to
the
community
to
provide
this
100
channels
for
2a
to
enway
communications.
A
Yeah
and
how
you
do
that
is
going
to
be
involve
some
very
fun
cool
software
I
think
in
in
the
system,
or
you
may
have
a
different
way.
You
can
figure
the
whole
thing
in
mind
that
I
I
haven't
come
up
with
yet
which
is
entirely
possible,
but
this
is
the
way
I
wanted
you
to
understand
the
way
my
brain
was
working
on
this.
So,
if
you're
trying
to
optimize
this,
what
you're
trying
to
do
really,
I
think,
is
first
try
and
get
the
downlink
down
here
in
the
bottom.
We
can
go
back.
B
A
B
C
B
A
A
C
C
A
A
D
B
B
A
I
I
I
think
the
fact
that
we're
having
this
discussion
would
tickle
a
member
of
the
federal
communication
commission
to
think
that
we
actually
are
thinking
about
this
trade
factor
that
we
don't
want
to
present
crap
to
our
users.
That's
right
and
we
do,
and
we
want
to
be
good
shepherds
of
our
spectrum,
so
we're
struggling
with
this
number.
So
what
I
would
tell
you
guys
is
this
number
to
me,
along
with
a
channel
count.
They
set
the
way
the
real
transponder
system
works.
C
A
If
there
is
only
one
kind
of
channel
now,
you
guys
could
tell
me
well,
I
could
break
this
transponder
up
into
multiple
transponders
each
with
its
own
data
stream
set,
so
that
maybe,
rather
than
having
three
tdm
a
one
tdma
link,
I
have
two
or
three
tdm
links.
One
is
for
voice,
one
is
for
for
data
and
the
others
for
some
kind
of
video
link.
B
B
B
A
No,
I
I
assume
you
wouldn't
build
in
a
codec,
but
this
still
is
what
that
6.252
is
telling
me
is
that's
the
average
data
rate
that
I
want
to
achieve
for
the
average
user,
regardless
of
elevation,
angle
and
location,
and
that
that
number
will
ultimately,
along
with
the
downlink
performance,
that
898.96
kilobits
per
second.
That
will
tell
me
how
many
channels
I
I
have
available,
given
the
the
the
the
herb
I
have
from
the
transponder
right
totally.
A
That
so,
when
I
give
you
guys,
when
I
give
you
guys
this
adjusted
spreadsheet
you're,
taking
into
account
whatever
changes,
we
make
because
of
say
that
you're
not
using
dvd
on
the
uplink
that
then
that,
then
you
guys
can,
along
with
the
user
community
and
people
who
are
helping,
you
can
socialize
this
and
figure
out
what
that
number.
What
everybody
wants
that
number
to
be,
but
it's
it's
it's
one
of
the
key
parameters.
A
A
Yeah,
okay,
okay!
So
you
what
you're
doing
is
you're
you're,
you're
channelizing
the
bits,
whereas
what
I'm
doing
is
letting
the
bits
change
and
I'm
trying
to
express
that
as
a
channel
count.
So
I'm
using
as
a
variable
the
channel
count
you're
keeping
the
channel
count
constant
and
adjusting
other
parameters
to
to
make
that
work
so
that
that's.
A
C
B
A
You
know
this
is
a
complicated
thing
we're
doing
here.
So
that's
right,
I
I'm
just
showing
you
my
slice
at
it
in
the
way
in
in
the
way
it
evolved
in
it
evolves
in
in
the
case
of
this,
in
the
expression
of
this
link
budget
because
of
all
the
prior
experiences
I've
had
with
both
amateur
and
commercial
communications
and
everything
else.
It's
the
synthesis
of
everything.
A
B
D
B
A
Right
right
well,
and
and
that's
okay
for
that
step-
okay,
all
right!
All
right!
Let
let
me
think
about
that
for
a
minute,
and-
and
so
we
aren't
here
till
midnight
tonight,
my
time
we
probably
should
kind
of
move
on
here.
So
what
I've
got
here
is
now
we're
going
to
talk
a
little
bit
about
the
orbit
and
how
the
orbit
figures
into
this
whole
thing
along
with
with
antennas
and
stuff.
So
this
comes
from
many
many
of
my
old
spreadsheets.
This
is
just
a
a
mini
orbit
summarizer
here
which
actually
works.
A
If
you're
just
thinking
about
orbits
it
actually
dynamically
computes
some
things,
and
maybe
you
don't
need
them
all
here.
But
the
key
point
is
you
want
to
set
the
in
my
blue
boxes.
You
want
to
set
the
apogee
height
and
that's
the
height
of
a
geo
orbit,
35
786
and
then
died
to
the
perigee.
Let's
talk
about
that
for
a
second,
we
go
back
to
the
the
iridium
and
one
web,
one
webb
and
friends,
and
that
is
that
these
guys
are
going
to
say
they
own
these
altitudes
and
the
highest
altitude.
A
Thing
and
you'll
see
that
you'll
see
that
reflected
in
that
delta
v
calculation
document,
which
I
also
gave
you
so
anyway.
If
we
do
1250,
it
means
we
fly
over
the
heads
of
all
those
other
constellations
which
are
down
here
buzzing
around
the
earth,
so
we're
a
little
bit
above
those.
So
even
our
perigee
doesn't
cross
through
the
orbits
of
all
this
god-awful
ngso
fss
mayhem
nightmare.
That's
going
on
that
spacex
is
creating
okay
and
we
go
up
to
we
just
kiss
the
geo
altitude.
A
I
mean
you
know
you
might
make
that
a
few
kilometers
less
or
something
so
we
technically
never
get
into
the
geo
world
either
depends
on
how
you
want
to
play
this
game.
I
can
tell
you
that,
when
you're
launched
into
these
orbits,
there
tends
to
be
an
apogee
bias
on
them,
so
that,
rather
than
going
to
35,
786
they'll
really
put
you
at
about
36
300.
A
and
since
we'll
be
riding
with
some
geo
operator,
who's
going
to
own
that
rocket
they're
going
to
set
the
apogee
but
realize
they're,
probably
going
to
set
the
apogee
a
little
bit
above
the
geo
altitude
that
helps
them.
For
some
reason
in
their
propellant
management,
I
never
exactly
understood
why
the
geos
do
that,
but
they
do
it
all
the
time,
so
you
might
be
in
a
starting
orbit-
that's
36,
300
or
so
by
by
250.
A
So
what
we
have
to
do
is
take
it
up
from
220
to
250
up
to
this
1250
and
that
burn
cost
is
about
100
meters
per
second
all
right.
So
now
what
we
do
is
we
care
about
how
we
perform
as
we're
at
these
various
points
along
the
orbit.
So
I
just
made
a
list
here
and
I
called
perigee
one
and
apogee
13
and
I
put
down
here
14
for
somebody
wants
to
put
some
in
between
values.
That's
that's
a
user
defined
parameter
there,
so
at
14.
I
can
go
put
in
these
parameters.
A
I
just
have
to
change
whatever
the
mean
anomaly
I
want
to
look
at
is,
and
it
will
calculate
the
other
stuff
for
me
and
don't
worry
about
this,
but
there's
some
subtleties
about
the
amount
of
the
earth.
You
see
and
what
the
noise
temperature
will
be.
I
see
if
they've
lost
that
value.
That's
supposed
to
be
the
noise
temperature
of
the.
A
A
This
alpha
value
is
what
am
I
going
to
do
with
the
bore
side
of
the
the
main
antenna
that
I'm
pointing
this
spacecraft
with?
In
other
words,
I'm
going
to
point
if
this
is
a
dual
frequency
antenna,
I
think
you
said,
then
the
bore
side
of
that
antenna
could
be
offset
from
the
line
of
the
the
instantaneous
line
between
the
center
of
the
earth
and
the
center
of
the
spacecraft.
A
That
cell
allows
me
to
offset
the
angle
of
that
antenna,
but
what
I'm,
assuming
by
putting
that
at
zero,
is
that
alpha
is
always
zero,
regardless
of
which
case.
I
pick
between
case
one
and
case
thirteen.
So
another
way
of
saying
is:
I'm
always
nader.
Look
us
yeah,
I'm
always
nader.
Looking
with
that
antenna,
so
is
that
okay.
A
D
A
A
Yeah,
that's
that
that's
the
rest
of
my
sentence
there.
There
is
a
problem
with
dumping,
the
momentum
from
the
wheels
and
we
had
it
in
the
old
phase
3
program
as
well.
We
were,
we
were
controlling,
we
didn't
have
star
trackers.
We
had
sun
and
earth
sensors,
but
we
had
the
same
requirement
that
we
had
to
dump
momentum
from
the
wheels
or
from
the
spacecraft,
at
least
because
it
was
a
spinner
spacecraft.
A
So
our
wheel
was
the
spacecraft
itself,
but
be
that
as
it
may,
we
did
have
to
remove
momentum
and
dump
it
and
the
only
place
we
can
do
that
is
at
the
perigee
of
the
orbit.
That's
another
reason
for
setting
that
perigee
as
low
as
we
dare
it.
It
also
will
reduce
our
delta
v
to
razor
and
lower
the
system,
but
it
also
sets
the
amount
of
time
we
can
effectively
torque
to
remove
the
to
dump
the
momentum.
A
Angular
momentum,
okay,
okay,
yep,
all
right,
so
the
rest
of
this
in
the
yellow
table
here
is
describing
where
we
are
with
respect
to
the
antenna
roll-off
and
everything
and
let
let's
let's
go
to
another.
This
is
a
summary
chart
to
allow
you
to
to
see
how
well
you're
doing
and
to
set
the
two
import.
What
you're
doing
on
this
page
is
setting
two
parameters.
One
is
which
step
case
am
I
going
to
use
in
effect,
how
high
up
is
the
spacecraft?
A
That's
going
to
be
important
to
the
link
budget,
so
it
knows
the
range
it's
got
to
communicate
over
and
it's
telling
you
if
I'm
at
step
13,
I'm
at
35
786
altitude.
If
I'm
at
step,
let's
pick
another
one,
nine,
then
the
range
goes
down
to
13
399
kilometers,
so
that
adjusts
that
one,
the
other
thing
is
think
about
the
users
in
this
model
by
virtue
of
their
elevation
angle
as
the
most
important
parameter.
A
If
I
put
in
10
degrees
here
as
I
have,
it
means
the
locus
of
points
all
around
the
earth
in
a
ring
of
all
those
users.
Would
that
would
be
at
10
degrees,
elevation
angle,
give
or
take
okay.
So,
when
I
put
in
an
elevation
angle,
think
of
not
one
user,
but
all
the
users
that
have
that
elevation
angle
and
this
link
would
work
for
all
of
them.
A
A
No,
I
do
not
put
doppler
in
here.
I
could
put
doppler
easy
enough
in
this
great
great
table
here.
If
we
put
it,
we'd
have
to
we'd
have
to
decide
whether
we
wanted
to
do
well.
We
could
put
it
both
in
upland,
doppler
and
downlink
doppler
could
be
put
in
this
table,
and
that
would
be
the
appropriate
place
to
do
that.
Okay,
yeah,
that
that
that's
a
good
suggestion.
A
So
we
know
what
what
that
would
be
good
good
point.
Indeed,
I
tried
on
these
yellow
parameters
to
define
a
little
more.
What
what
I
was
really
talking
about
here,
but,
as
you
can
see
by
by
driving
this,
if
I
change
these
links
over
here,
I
can
immediately
tell
what
I've
done
to
my
c
over
in
plus
I
zero
that
that's
the
end
ultimate
link
result
on
the
uplink
and
the
down
link.
I
think
I
got
that
right.
A
Well,
the
drift
rates
are
there.
The
the
the
omega
dt
is
how
much
the
argument
of
parity
changes
in
the
capital
d
omega
dt
is
how
much
the
right
ascension
changes,
the
orbit
plane,
changes
in
degrees
per
day
say
again.
Okay,
so
those
are
in
okay,
and
it's
telling
you
also
what
the
period
the
nominal
period
of
the
orbit
here
we
go
all
right.
I
can't
I
can't
draw
my
own
there.
Okay,
now
I
got
it
all
right
so
over
here
on
the
right.
What
we
have
is
a
pictogram
of.
A
What's
going
on,
you
see
that
parameter
up
there
at
the
top
alpha
again.
So
that's
how
much
I'm
off
off
pointing
this
thing,
but
it's
telling
you
now
where,
with
respect
to
the
user,
is
this?
Is
this
beam
I'm
going
to
go
into
place
the?
So
you
can
see
that
the
zero
elevation
angle,
which
is
there
is
the
row
parameter
here,
is-
is
defined,
so
you
can
see
how
much
of
the
earth
is
illuminated
by
in
in
degrees.
A
A
But
anyway
again
I
can
see
what
uplink
and
downlink
I've
achieved
is,
and
these
are
all
this
is
just
an
observation
table.
You
don't
change
anything
in
this
table
because
you'll
see
there's
nothing,
that's
blue,
but
you,
the
main
thing
is,
you
can
see
for
this
user
at
10
degrees,
elevation
angle,
how
much
downlink
beam
roll-off
has
occurred
and
how
much
uplink
beam
roll-off
has
occurred.
D
A
It's
not,
it
isn't
quite
so
easily
reflected
here
and
you'll
see
that
okay,
so
we've
got
done
with
the
with
sort
of.
This
is
where
you
can
visualize,
what's
happening
with
the
orbit
in
particular,
what's
happening
with
respect
to
the
beams
and
the
real
thing
to
notice
it.
That's
that's
going
to
interact
here
is,
as
I
come
away
from
apogee
and
start
moving
more
toward
perigee.
A
A
Okay,
all
right
we'll
come
back
to
this,
but
the
next
thing
is.
I
realized
that,
because
this
is
a
rain
rain
model
that
the
location
of
the
user
is
going
to
make
a
big
huge
difference.
So
what
I
wanted
to
do
was
be
able
to
plug
into
the
case
you're
studying
very
quickly.
A
place
where
you
can
change
the
the
user
so
right
now,
we've
got
number
nine
in
there.
So
that's
boulder
colorado,
that's
an
intentional
choice
because
I
consider
it
sort
of
the
average
rain
loss
location
in
the
whole.
A
Us
it's
not
a
wet
place
and
it's
not
a
dry
place
and
it's
a
place
where
there
are
lots
and
lots
and
lots
of
meteorological
measurements
made
because
noah
is
there
in
cars
there.
Everybody
who
knows
anything
about
weather
is
in
boulder,
so
you
can
find
out
the
weather
conditions
in
boulder
better
than
any
place
on
planet
earth.
So
that's
that's
why
I
use
that
as
a
reference
location.
A
A
A
A
It
will
affect
these
links,
but
it's
part
of
the
fun
of
playing
this
game.
You
know
like
if
you're,
if
you're
working,
20
meters,
you
you
really
care
about
what
what
the,
what
the
mean
free
path
is
and
what
frequency
muf
the
max
usable
frequency
is.
If
you're
working
20
meters
you
care
about
that,
if
you're
working,
10
meters,
it's
even
more
important,
so
all
of
amateur
radio
with
respect
to
propagation
is
a
game
play
and
that
is
no
different
with
millimeter
wave.
A
I
think
it's
exciting,
because
amateurs
will
learn
so
much
about
rain
losses
from
what's
going
on
here.
So
the
one
of
the
benefits
of
amateur
radio
here
is
when
you
learn
about
new
phenomena
and
meteor.
Scatter
is
a
perfect
example:
where
hams
were
the
best
meteor
scattered
guys
around.
They
could
tell
you
more
about
meteorite
propagation
than
any
specialist
in
the
entire
world,
so
it's
a
place
where
we
can
shine.
So
I
love
the
fact
that
the
the
rain
plays
a
game
with
you
here.
A
A
So
I
figure
we
might
as
well
use
it
to
advantage,
and
so
this
is
kind
of
the
reason
I
put
this
particular
page
in
is.
We
can
play
games
with
that
and
see
how
this
is
actually
what
difference
it
makes
guys
if
you
do
that.
Okay,
the
next
one's
the
standard
gobbledygook
you
got
to
put
in
the
mean
uplink
frequency
and
the
mean
downlink
frequency,
and
this
just
displays
the
bandwidths
the
path
losses.
It's
a
summary
to
give
you
the
elevation
angles
again,
almost
every
data
sheet.
It
gives
the
slant
range.
A
A
A
So
you
have
to
you,
have
to
know
for
your
sspa
or
hpa
that
you're
using
what
the
what
the
like
the
one
dvd
compression
output
power
is,
how
much
you
want
to
back
it
off
at
that
back
off
point.
What
is
the
efficiency,
because
it's
also
going
to
tell
you
how
much
spacecraft
power
you
need
on
the
final
page.
It
tells
you
okay,
I
mean
this
many
rot
watts
if
you
run
and
run
the
system.
This
way.
D
A
And
then
you
have
to
measure
probably
either
the
noise
power
ratio
version
of
the
inner
mod
or
the
third
order,
intermod
products,
whatever
you
want
to
do
and
you
you
can
represent
that
there,
but
that's
actually
used
in
the
final
to
actually
subtract
off
the
power,
that's
creating
the
inner
mod
from
the
useful
power
of
the
transmitter.
So
it's
actually
used
in
this
in
this
in
this
system
to
to
offset
the
power
that
that's
wastefully
used
in
producing
innermod
right.
So
it's
telling
your
ear.
A
Okay,
so
this
system,
with
those
parameters,
it's
going
to
take
you
35.7
watts,
to
run
that
10
watt
transmitter.
Okay,
then,
over
here
it
allows
you
you
can
change,
but
these
two
parameters
are
are
adjusted
on
it
put
in
another
page.
This
is
put
in
in
the
tab.
Three
link
scenario
planner-
and
this
is
also
put
in
the
link
scenario
planner.
So
this
is
just
reflected
here.
I've
got
one
channel
and
that
channel
is
one
megahertz
wide,
I'm
using
it
adaptively,
which
is
a
a
bit
of
a
lie
you
can.
A
This
isn't
used
anywhere,
it's
just
a
helpful
thing
to
you
to
tell
you
and
how
you're
actually
adapting
it
could
be
variable,
adaptive
or
constant
or
fixed.
You
know
whatever
you
want
to
put
in
there,
you
can,
but
it
it
it.
It
also
can
be
used
for
modulation.
So
if
it's
vpsk
or
2psk,
you
can
put
that
in
there
and
then,
if
you
have
multiple
channels,
it
will
divide
up
the
channels
into
the
number
of
megahertz
or
killers
per
channel
and
the
allocated
power
to
a
given
channel.
A
A
Then
it
shows
you
a
little
pictogram
of
what
the
transponder
looks
like
and
it
gives
you
the
ability
to
change
all
these
parameters
so
without
I
think
without
belaboring
the
obvious,
the
one
that
you're
going
to
be
most
interested
in
generally,
here's
by
the
way
where
you
put
the
antenna,
pointing
loss-
and
it's
telling
me
that's
coming
from
another
data
sheet
too
that's
over
in
the
orbit
4a
in
the
orbit.
It
allows
you
to
set
the
pointing
loss,
but
the
one
you're
going
to
care
about
is
the
I
I
have.
A
A
A
Then
you
can
set
all
the
all
of
the
usual
things
that
you
have
to
set
for
the
noise.
That's
established
the
system,
noise,
temperature
for
the
system
and
then
over
here
on
the
transmit
side.
It's
telling
you
yeah
you
picked
up
before
you
picked
up
10
watts,
then
it
allows
you
to
have
filter
losses
and
line
losses.
Going
to
that-
and
it
says
your
antenna
gain
is
17.2.
A
A
Let
me
see:
let's
go
to
it:
it's
entered
in
on
4a
cell
k-36,
okay,
so
4a
cell
k
36,
oh
it's
taken
from
there,
but
if
this
is
what
this
is
a
double
indirect,
okay,
36,
okay
and
that's
a
complicated
formula,
it's
saying
I
gotta
remember
my
own.
This
is
this
is
when
you
forget
this.
It's
called
bit
rot.
A
A
Oh
it
does
it
does
I
mean
I
can
cheat
and
go
to
the
to
the
to
the
link
itself.
Let
me,
let
me
do
say.
The
uplink
and
you'll
see
that
now
this
is,
if
nothing
else,
this
should
be
fairly
clear.
This
is
the
straightforward
link
link
itself
and
if
I
come
down
here
and
I
look
the
ground
station
antenna
pointing
loss,
so
I
got
the
ground
station
antenna
pointing
loss,
but
I
also
have
the
spacecraft
pointing
loss
here.
Spacecraft,
receiver,
pointing
off
is
here
k-37.
A
So
it's
telling
me
it's
so
it's
it's
based
on
on
a
calculation
of
some,
some
relative
I'll,
take
an
action
item
on
this
and
explain
to
you
how
it's
done
that
it's
it's
flummoxing
me
right
now,
but
let's
go
then
back
to
here,
so
we're
still
calculating,
but
you
see
there's
a
lot
more
now.
Okay,
here
it
is
here
it
is
okay,
so
the
tran
this
is
this
is
to
properly
define
the
antennas
now
you'll
see.
A
We
have
our
friend
over
here
this
this
this
graphic
again,
because
it's
useful
in
setting
these
to
see
what
it
does.
What
we
got
is
a
frequency
of.
Thus,
and
so,
if
the
antenna
now,
this
assumes
a
a
guys.
This
is
like
what
kind
of
every
antenna
is
going
to
have
a
different
kind
of
equation
to
set
its
gain
relative
to
in
its
beam
width
relative
to
some
parameter
of
the
antenna.
A
So
just
assume
that
this
is
a
dish
that
I'm
doing
it's
the
size
of
the
dish
that
I
would
need
with
this
aperture
efficiency
in
order
to
produce
this
gain,
and
it
has
this
beam
width.
So
I
was
right
on
the
beam
width,
okay,
so
an
antenna,
that's
70
centimeters
across
at
10.5
gigahertz,
and
there
is
no.
There
is
no
there's
no
parabola.
A
There's
no
dish.
That's
going
to
have
an
80
aperture
efficiency,
a
good
high
one
would
be
60
couple
percent.
So
this
is
telling
me
this
is
a
horn
antenna.
They
have
about
80
efficiency
and
their
aperture
size.
Isn't
that
different
from
so
this
is
a
little
bit
of
a
fudge,
but
what
you
want
to
do
is
get
the
approximate
antenna
parameters
between
the
antenna
diameter,
if
you
call
it
the
equivalent
of
a
dish
and
it
the
equivalent
of
dish.
A
A
A
Yeah,
it's
the
half
beam
width,
that's
right!
It's
the
half!
It's
it's!
It's
one!
Half
the
half
power
beam
with!
Oh
you
see
it's
there,
half
power
being
divided
by
two,
so
it's
a
half
power
beam
with
divided
by
two,
that's
correct.
So
that's
this
from
the
bore
side
to
where
the
user
might
be
located.
Now
what
this
yellow
line?
This
is
a
dynamic
yellow
line.
This
is
this
is
using
dynamic.
This
is
using
dynamic,
color
control,
and
this
is
one
of
the
new
features
I've
been
able
to
thread
into
this.
A
For
this
link,
the
yellow
line
is
the
condition
I'm
meeting
right
now
on
the
uplink
okay.
So
at
this
time
I'm
this
is
the
closest
step
that
I
I
I'm
achieving
that
I
have
in
this
step.
So
it's
a
it's
like
a
look
up
it.
It
isn't
like
a
looked
up
table.
It
is
a
lookup
table
and
it's
looked
up
and
said:
okay,
you're
at
7.98
degrees,
off
seven
point
something
degrees
off,
and
that
this
is
the
closest
step
and
you're.
A
Inside
the
three
db
beam
width
in
transmit,
however,
over
here
in
the
received
side,
we
got
a
different
situation.
The
half
power
beam
width
is,
is
8
degrees,
not
13,
and
a
half,
so
it's
a
narrower
antenna
and
because
it's
a
narrow
antenna,
I'm
already
I've
already
what
I'm
achieving
at
8.02
degrees
is
I'm
achieving
minus
3.03.
So
I'm
already
just
slightly
past
the
3db
rolloff
point
on
the
antenna,
as
I
change
the
link
parameters,
this
yellow
line
dynamically
moves
up
and
down
the
page.
A
A
A
So
we
can.
We
can
show
some
of
the
cases
here,
but
you
have
to
be
aware
of
the
fact
that,
as
you
move
away
from
apogee,
if
the
beam
can't
adapt
that,
then
two
things
happen,
one
is
you're
going
to
be,
the
user
will
be
fir
just
on
average.
The
user
will
be
further
off
the
beam
boar
site
and,
second
of
all,
to
the
good
side
you,
the
spacecraft,
will
be
closer
to
the
earth,
so
one
over
r
squared
is
a
lower
path
loss,
so
the
link
will
just
improve
because
the
path
loss
decreased.
A
A
If,
if
you
play
with
his
antenna
here-
and
I
say
yes,
then
it
will
apply
to
the
link
equations,
the
link
budget,
this
antenna,
which
has
this
gain,
and
this
beam
width.
If
I
select
no
here
it
goes
over
and
it
will
select
the
gain
that
you
picked
off,
that
other
choice
on
the
link
scenario.
Planner,
let
me
do
that
real
quick.
A
There
is
up
here
at
the
top
in
the
link
scenario
planner.
You
can
check
this
box
and
uncheck
these
boxes
and
then
you'll
be
using
that
particular
size
antenna,
and
I
this
is
a
little
bit
complex.
I
agree
and
you'll
be
controlling
from
this
box
here,
but
you
see
it
tells
me
I've
not
selected
this.
If
I
say
no,
then
it
says
selected
over
here
and
not
selected
over
here.
A
A
So
I
have
to
go
down
here
and
say:
nope,
I'm
not
going
to
use
this
antenna
now,
I'm
operating
in
what
you
might
call
a
a
duplexer
diplexer
mode,
where
I
have
the
same
antenna
and
it
goes
through
to
a
diplexer
and
you
sort
the
transmit
frequency
in
the
receive
frequency
in
the
diplexer
and
then
you've
got
two
coax
cables,
one
going
to
the
transmitter
one
going
to
the
receiver,
so
you
can
do
either
mode
of
of
performance.
Here
you
can
have
the
assume
the
user
has
two
antennas
or
one
antenna.
Yeah.
B
B
D
A
All
right,
so
we
got
the
the
user
terminal
sorted.
So
I
I
can
what
I
did
here
in
announce
going
back
to
not
how
you
might
use
the
spreadsheet,
but
how
I
am
using
the
spreadsheet
is
I
put
a
one
meter
antenna
in
for
transmit
and
receive
so
I
could
play
with
these
parameters.
While
I
was
doing
it
and
I've
got
60.
Aperture
efficiency
would
be
like
an
offset
fed
user
antenna.
So
I
assume
that
the
the
user
is
using
a
microwave
antenna.
A
He
would
have
bought
from
his
tv
dish
store
where
he
where
he
would
get
it,
and
then
he
modifies
the
feed
for
his
use,
but
but
basically
it's
an
offset
fed
antenna.
So
it's
a
little
tricky
to
point
for
the
average
user
because
of
course
it
doesn't,
the
the
boresight
doesn't
align
with
any
physical
feature
on
the
dish.
So
it's
hard
as
hell
to
make
sure
you
can't
just
go
out
with
your
eye
and
look
at
some
reference
point
in
the
sky
like
a
star
and
say:
okay,
I'm
about
right.
A
You
got
to
calibrate
your
system,
but
but
anyway,
that's
what's
in
here.
Right
now
is
the
cheapest
antenna
I
could
get
for
a
guy
was
a
offset
fed
one
meter
dish
and
it
already
has
a
beam
width
at
our
frequency
of
0.87
degrees,
which
is
damn
narrow
and
the
same
and
the
same
size
antenna
down
here
for
the
user
on
the
downlink,
which
goes
michelle
to
the
to
the
issue
of.
A
If
I
make
it
easier
for
receive
than
transmit,
then
he
can
slop
around
in
two
degrees
right,
which
is
still
pretty
damn
narrow,
but
he
could
slap
around
in
two
degrees
rather
than
having
to
try
and
point
to
.87
degrees,
which
he
needs
for
transmit
right,
also
with
transmit.
He
might
be
able.
If
you
put
the
right
feature
software
feature
in
the
spacecraft,
he
might
be
able
to
walk
him
himself
in
if
he
gets
feedback
from
the
spacecraft.
Saying.
A
Okay,
your
signaling
noise
racer
right
now
in
the
channel,
I'm
receiving
you
on
using
some
gui
or
something
is
you
know,
is:
is
6
db?
Oh
no!
Now
it's
eight!
Oh,
it's
nine!
Okay,
so
you
say
he
uses
that
to
walk
in.
He
can
walk
in
the
transmit,
whereas
he
needs
the
feedback.
He
gets
from
his
receiver
to
to
to
lock
in
the
downlink
beam
right
and.
C
A
Yeah,
so
this
is
the
area
for
the
ground
station,
where
you
put
in
whatever
the
lna
temperature
is
noise
figure
I
don't
have.
If
you
want,
I
can
put
in
noise
figure
here
and
I've
got
a
little
calculator.
I
can
put
a
little
calculator
over
here
in
the
empty
space
which
allows
you
to
go
from
noise
figure
to
noise,
temperature
and
noise
temperature,
because
hams
are
needing
that
all
the
time.
So
we
can
do
that,
but
anyway,
I've
got
it
in
proper
engineering
terms.
So
it's
it's
noise
temperature.
A
A
A
A
C
A
Yeah,
okay,
okay,
so
then
we
go
to
the
links
proper,
and
this
should
look
like
a
properly
documented
and
annotated
link
budget
and
the
most
important
part
of
it.
It
does.
It
looks
pretty
much
regularly
like
you'd
expect
to
see
it's
got
all
the
pointing
losses
it's
properly
computing
and
a
parameter
you
need
to
know
is
the
actual
ratio
of
the
antennas
you're
using
so
you'll,
see
where
the
hell
is.
My
actual.
A
A
A
Polarization
loss:
okay,
that's
a
big
big
one!
This
it's
the
main
spreadsheet
that,
where
you
have
to
put
the
polarization
loss
you
guys
from
some
of
my
other
either
get
one
of
my
other
regular
image.
Radio,
spreadsheets
or
you
can
implement
the
formula
yourself,
but
you
need
to
know
the
actual
ratio
of
the
transmit
antenna,
the
actual
ratio
of
the
receiver
antenna
and
then
the
angle
between
the
two
ellipses
that
are
created
by
the
two
antennas
when
their
axle
ratios
aren't
perfect.
A
And
what
this
is
telling
me
is
that
the
actual
ratio
of
the
ground
station
antenna
was
1db.
The
spacecraft
antenna
was
3db
and
the
and
the
it's
the
worst
case,
ellipse
alignment.
So
the
two
ellipses
thus
created
are
in
in
as
cross
polar
as
they
can
get
and
under
those
conditions
where
I
have
a
one
in
three,
the
the
the
loss
is
minus
0.23.
A
A
C
A
A
D
A
A
D
A
All
right
so
anyway,
so
this
is
just
everything
standard,
except
what
I'm
doing
here
is
I'm
allowing
you
to
pick
between
I'm
separately
once
we
get
into
the
part
where
the
the
rain
losses
occur.
All
the
rain
losses
which
are
coming
from
the
the
rain
model
are
plugged
in
here,
and
these
are
the
sums
of
them
and
then
I
from
here
on
down
the
link
budget,
I
compute
the
the
rain
case,
the
rain
on
case
of
the
rain
off
case,
and
that's
what
you
you
see
these
two
parallel
numbers.
A
You
see
them
again
here
and
here
and
here
so
each
time
I
apply
some
correction,
there's
two
versions
of
the
of
the
outcome
and
they're
carried,
and
then
I
copy.
If
I
turn
on
the
rain,
it
copies
the
worst
value.
If
I
turn
the
rain
off,
it
takes
the
best
value
in
in
each
case,
but
the
things
I
correct
for
here
are
the
those
the
met
losses.
A
A
Interference
on
the
downlink.
If
I've
got
an
adjacent
if
I've
got
an
interfere
or
interference
environment,
I
mean
let's
say
I
have
something:
that's
producing
white
noise.
That's
going
all
over
my
receiver
channel!
I
can
put
in
the
density
of
that
noise
here
and
it
and
it
computes
the
noise
power
of
that
and
then
it
figures
out.
How
much
does
that
degrade?
The
link?
D
A
Okay,
you
see
the
link
goes
to
crap,
because
I
I
put
a
very
high-
that's
a
fairly
high
interference
density
into
that
case
into
that
scenario,
then
I
I
end
up
with
the
classic
signal
to
noise
ratio.
That's
okay!
It's!
But
it's!
The
signal
to
noise
ratio.
Kick
considering.
The
noise
also
includes
an
interference
and
that
interference
is
defined
by
that
blue
box.
Above
so,
if
I
turn
off
the
interference
so
that
it's
really
see
if
our
n
plus
I
but
I
is
zero,
then
it
becomes
c
over
n
anyway.
A
A
A
Some
people
would
like
to
know
what
the
net
eb
over
n0
parameters,
it's
another
way
of
saying
the
signal
noise
ratio,
but
it's
the
energy
per
bit
to
noise
power
density
number,
and
so
that's
given
here
as
well.
Okay,
so
the
this
part
down
here
is
where
I
here
isn't.
There
is
an
implementation
loss
taken
into
consideration
here,
but
I
am
since
I've
essentially
disabled
everything
down
here,
because
I'm
I'm
going
on
to
the
to
the
the
mod
cod
tables
and
I'm
using
a
dvds
dvds2
demodulator.
A
So
fundamentally
I
I
haven't
really
used
this,
but
here's
an
example
where
I
put
the
implementation
loss
into
the
into
the
so
prior
use
of
this
spreadsheet.
I
was
apparently
using
it
for
a
bpsk
link
and
I
had
assumed
that
the
dmat
had
a
half
db
implementation
loss.
Okay,
okay,
now,
if
we
go
to
the
downlink,
the
only
thing
that
might
be
different
here
that
you
haven't
seen
before
is
I
calculate
from
the
inner
mod
value.
A
That's
in
here
I
calculate
the
inner
mod
power,
so
I
say:
okay,
I
got
a
10
watt
transmitter,
but
I'm
producing
the
inner
mods
20
db
down,
say
so
I
have
an
inner
mod
of
0.1
db,
so
that's
20
db
below
10
watts,
so
I'm
losing
to
the
inner
mod
0.1
of
a
db.
So
the
real
power
I'm
actually
transmitting
on
the
link.
That's
doing
some
good
at
the
d.
Mod
is
9.9
watts.
A
So
if
I
were,
for
instance,
to
go
back
and
make
the
inner
mod
value-
which
I
think
is
all
the
way
back
here-
yeah
it's
a
spacecraft,
never
mind,
isn't
it
here's
the
spacecraft
theater
mod?
If
I
make
it
the
like
a
class
c
amplifier
or
something
where
it's
really
crappy
you'll
see
now
what
happens
now?
The
downlink,
which
is
still
10
watts,
is
losing
1
watt
of
power
to
the
inner
mod,
and
it's
only
producing
9
watts
of
real
power.
C
A
In
that,
in
that
regard,
you
have
to
know
what
the
efficiency
hit
is
for,
given
inner
months,
if
I
measure
15
and
so
it'll
also
the
way
you
will
adjust
that
normally
and
the
big
guys
when
they
do
their
transponders,
they
just
have
a
variable
attenuator
and
they
set
an
attenuator
and
that
will
set
the
output
back
off.
So,
if
I
back
it
off,
say
3db.
A
Then
I
might
have
improved
linearity,
so
I
might
get
say,
25
db
linearity,
so
I've
got
that
trade-off,
but
I
now
only
have
five
watts
of
power
driving
the
link,
but
it's
a
much
more
linear
link
and
by
the
way
this
in
the
bargain.
This
number,
if
I
went
to
a
higher
output
back
off,
the
efficiency
might
go
down
to
like
20.
A
So
that
might
be
the
the
circumstances
for
a
fairly
linear
transponder
with
a
pretty
big
back
off,
and
I
don't
know
if
that's
enough
back
off
to
get
25
db,
that
might
have
to
be
6
db
or
something
like
that.
But
anyway
the
you'll
pay
for
it
with
efficiency.
Now
you
can
go
see
how
it
affects
the
links,
and
you
can
see
that
my
transponder
power's
gone
up
to
50
watts
so
to
get
10
watts
out.
I
now
need
50
watts
of
power
in
to
make
that
system
work.
A
Okay,
so
with
that
discussion,
this
link
looks
a
lot
like
the
other
one
there.
Here's
all
the
rain
effects
and
you
can
see
the
rain
effects-
are
much
smaller,
because
this
is
at
10,
gigs
and
so
on
and
the
same
things
apply
here
and
there's
the
net
result
in
in
c,
over
n
plus
I
and
the
numbers
I
really
care
about.
Are
these
two
numbers
here,
the
c
over
n
zero?
Plus,
I
zero
that's
what
I'm
using
in
in
the
mod
cod
tables.
A
Now
this
is
the
uplink
mod
card
table.
You'll
notice,
there's
a
yellow
line
across
here,
and
this
means
this
is
the
mod
cod
step
that
the
link
was
able
to
achieve.
So
I
I
look
over
here
at
the
red
number
and
I
see
by
the
way,
are
you
guys
generally
familiar
with
what
these
mod
pod
tables
look
like?
This
is
right
out
of
the
etsy
ddvs2
standard.
A
Okay
cool,
so
so
this
is
what
I've
made
adjustable
here
is
I
I
can
see.
I've
got
a
five,
a
five
percent
nyquist
roll
off.
So
this
is
a
very,
very
sharp
filter
and
I
might
say,
for
an
amateur
application,
you
might
be
able
to
use
10
or
even
20
nyquist
roll
off
and
nobody
would
care
and
it
would
save
probably
power
at
the
at
the
microprocessor.
A
A
A
Yeah,
I
think
fifteen
or
twenties,
so
I've
overspecified
that
one
so
you're,
right
and
and
so
okay,
so
that
now
changes
my
the
allowable
symbol
rate,
because
what
I
actually
said
here
is
the
hard
channel
limit,
and
then
it
says
well
how
many
at
that,
at
that
nyquist
roll
of
how
many
symbols
can
I
actually
cram
into
that
10
pillars
channel.
So
now
I
can
get
8.7
kilobits
killer
symbols
in
that
channel
anyway.
The
mod
type
that
was
achieved
was
this
particular
step
and
you'll.
A
I
could
because
the
downlink
is
the
hard
one
and
the
uplink
was
the
easier
one,
even
though
it
was
at
24
gigahertz.
So
what
you
guys
are
going
to
tell
me
is
I'm
going
to
replace
this
table
with
a
table.
That's
going
to
have
your
mod
code
steps
which
aren't
going
to
look
like
this,
but
I
need
the
data
for
to
create
this
table.
D
A
A
D
D
A
Well,
well,
I'm
actually
talking
about
case
case
where
the,
where
the
case
is,
though,
where
you
are
around
the
orbit.
Actually,
if
I
go
down
in
altitude,
I
don't
always
improve
the
situation
because
of
the
beam
roll
off.
So
some
users,
in
some
circumstances,
are
going
to
get
worse
conditions,
even
though
they're
getting
closer
to
the
earth,
which
is
a
a
sad
outcome,
but
it's
it's
part
of
it.
A
It's
part
of
what
I
call
the
game,
because
there
is
a
game
here
and-
and
you
just
have
to
as
an
amateur
you're,
not
going
to
get
everything
perfect
because
you
got
it
all
for
free,
so
you
have
to
get
what
you
get
and
and
and
that's
part
of
the
fun
of
the
whole
thing
and
that's
kind
of
the
way
I
looked
at
these
these
antenna
roll-offs
and
things
like
that
as
well.
Okay,
so
this
is
the
whole
downlink
list
and
you
can
see
we
can
go
from
a
mod
cut
step
of
1
to
28.
A
There
happen
to
be
28
steps
here,
and
that
takes
you
all
the
way
up
to
32
aps
k,
nine
tenths
and
all
the
way
down
to
qpsk
one
quarter
and
if
you're
at
qpsk,
one
quarter
that
should
be
about
you
know
in
your
mental
mind,
you'd,
say:
well:
q
pass
cad.
I
I
divide
by
two
I
multiply
by
two
and
by
doing
half
a
quarter
rate.
I
I
I
divide
by
four,
so
that
the
total
should
be
about
point
five
and
you
can
see,
give
or
take
bit
sampling
issues
and
overheads.
A
A
A
A
You
know
yeah,
this
is
the
uplink
budget.
Okay,
so
I
go
back
to
the
uplink
budget
and
I
see
the
number
I
got.
The
number
I
achieved
with
rain
off
was
45.89,
so
it
takes
the
45.89
and
it
looks
doing
the
lookup.
It
says
the
the
number
which
I
ex
exceeded
but
didn't
get
to.
The
next
step
was
45.81,
so
I
got
45.89
and
I
need
45.81.
A
A
So
I
put
in
all
the
mod
cut
steps
and
I
highlighted
the
s2x
ones
just
so
you
can
know
well,
did
I
land
on
one
of
the
old
steps
or
one
of
the
new
steps,
because
we're
actually
comparing
some
old
hardware
to
some
new
hardware?
So
that's
why
it's
highlighted
like
this,
but
at
least
you
can
tell-
and
you
can
see
on
the
down
link
here
with
what
we've
done.
A
A
A
A
A
A
There
so
now
we're
going
to
lay
down
like
now,
I'm
back
where
I
thought
this
should
be
so
I
had
too
much
uplink
antenna
game,
and
so
now
this
is
what
I'd
expect.
I've
got
just
around
about
a
bit
birds
and
I'm
getting
just
100.9
megabits
per
second
of
performance.
Out
of
that
link,
I
want
the
next
thing
I
want
to
show
you
is
how
now
how
the
rain
model
is
working
here.
A
So
it
actually
uses
the
rain
model
twice,
and
this
is
what
the
rain
model
gui
thing
that
the
itu
sends.
You
looks
like
you
can
see
it's
the
itu
here,
because
how
they're
spelling
degrees
in
french
all
the
green
parameters
are
plugged
in.
So
I'm
taking
from
that
user
selection,
I'm
plugging
in
his
latitude
longitude
height
and
whatever
elevation
angle
is
taken
from
that.
The
orbit
data
sheet
I've
put
in
his
downlink
antenna
size,
which
is
also
taken
from
tab
three
and
the
antenna
efficiency.
A
The
frequency,
this
polarization
parameter,
doesn't
seem
to
work
the
way
I
I
thought
it
was
so
I
just
put
45
in
there
and
leave
it
alone.
I
think
it's
assuming
a
linear
antenna
and
that
it's
a
geo
case
and
so
they're,
assuming
that
the
polarizations
are
misaligned
45
degrees,
I
don't
know,
and
then
it
wants,
the
rain
unavailability
and
the
one
most
everybody
uses
is
the
link
link
rain
ability,
availability,
not
the
unavailability.
A
So
this
is
copied
from
the
the
tab.
Three,
the
link
scenario
planner-
and
it's
put
here.
It
then
computes
that
number
there
and
then
that's
what
the
what
the
itu
rain
model
is
actually
doing.
Then
it
says:
okay,
if
you
have
that
location,
that
frequency
that
elevation
angle
and
that
set
of
antenna
parameters,
here's
what
your
here's,
what
your
weather
looks
like,
and
so
it
gives
you
for
99.5
percent
of
the
time.
A
A
It
tells
you
how
much
how
many
along
a
a
one
meter
column
it's
telling
you
what
the
weight
of
the
rain
would
be
in
that
column
and
it's
0.35
of
a
kilogram.
It's
telling
you
surface
water,
vapor
densities
and
innervate
integrated
water.
All
these
things
that
meteorological
meteorologists
would
ask
about,
and
then
it's
telling
you
also
well,
okay,
in
a
in
a
radio
sense
that
the
effective
temperature
of
that
of
that
whole
environment
you're
in
is
280
degrees,
kelvin
and
then
the
net
effect
of
that
on
the
link
is.
A
It
has
two
parameters
for
gaseous
attenuation.
The
number
you're
supposed
to
use
is
the
is
this
latter
one?
So
that's
really
the
effective
gas
law.
So
at
this
frequency,
which
is
24.025
gigahertz
at
in
boulder
colorado,
you
can
expect
without
any
rain
or
anything
just
the
atmosphere
is
going
to
kill
4.75
db
of
your
signal
going
in
the
uplink
direction,
and
if
you
on
top
of
that,
I
have
rain
and
clouds
you
get
this
additional
part
and
then
there's
something
called
scintillation.
A
The
way
I
like
to
think
of
it
is
well
if
I've
got
that
much
additional
attenuation,
then
maybe
I'm
not
uncertain
about
by
about
the
same
amount.
So
you
can
call
it
what
you
want,
but
it
throws
another
db
into
the
mix
and
then
the
one
you're
supposed
to
use
is
number
two
here,
so
we
have
for
boulder
colorado
on
a
clear
day.
We
got
at
this
10
degree
elevation
angle.
A
We
already
have
a
almost
12
db
of
losses,
so
that's
pretty
pretty
bad,
but
if
we
go
to
clear
sky
conditions-
and
we
only
count
the
the
gases
attenuation
and
the
scintillation,
you
see,
we
get
something
like
5.86
db.
So,
with
the
rain
off,
we
only
have
5.8
bb,
but
with
the
rain
on
it's
nearly
12
db
of
losses
and
by
the
way
another
useful
number
here
is.
If
I
look
up
in
the
sky
with
those
conditions,
that's
the
temperature
of
the
sky.
A
A
A
A
A
All
I'm
changing
for
the
link
is
just
the
guy's
elevation
angle.
Now,
that's
already
fed
into
that
link
model
back
there
for
the
uplink.
Now
it's
by
going
up
to
45
degrees,
the
noise
temperatures
drop
down
to
168
and
the
overall
atmospheric
loss
is
plus
scintillation.
It's
gone
down
to
4
db
and
without
any
rain
or
anything,
it's
dropped
down
to
1.3
7
db.
So
now
it's
become
a
kind
of
a
useful
radio
link.
Okay.
A
So,
by
setting
up
the
transponder
conditions,
you
can
actually
set
what
elevation
angle
practically
the
average
user
will
be
able
to
get
down
to
before
he'll
lose
the
link.
And,
of
course,
if
he's
in
a
wetter
location,
it's
going
to
be
he's
going
to
have
to
have
a
higher
elevation
angle
before
he
can
play,
whereas
if
he
gets,
you
know
a
higher
elevation
angle
and
he's
in
a
drier
place,
he's
going
to
do
better.
A
All
right
and
the
last
thing
is
a
summary
thing
that
shows
you
the
results
and
then
that's
just
there's
no
changes
in
that,
but
it
it
breaks
things
up
by
what
the
user's
parameters
are
on
the
uplink
on
the
downlink
and
then
what
the
spacecraft
parameters
are.
So
that's
all
summarized
there
and
then,
if
I
can
get
this
last
one
and
then
here's
a
pretty
picture
that
shows
what
everything
looks
like
as
you
go
through
the
system
from
one
end
to
the
other.
A
A
His
average
elevation
angle-
and
I
think
you
can
see
that
the
the
link
for
the
overall
system
performance,
how
many
channels
of
users
you
can
support
where
each
channel
in
my
definition,
was
a
voice
great
channel.
I
used
that
6.25
parameter,
but
that
can
be
a
different
parameter,
of
course,
but
in
order
to
get
100
channels
for
the
users
over
the
whole
range
of
different
parameters,
which
you
can
change
here,.
C
D
D
A
A
C
A
Yeah
well
so,
whatever
you
want
to
assume
there,
I've
assumed
that
we
use
the
old
number
we
used
to
use,
maybe
five
years
ago,
which
was
it's
pretty
hard.
So
we
we
don't
make
the
user
generate
more
than
one
watt
of
rf,
but
he
also
wants
a
small
antenna.
I'd
like
to
give
him
a
0.5
meter
dish,
but
instead
I
gave
him
a
one
meter
dish
to
make
the
uplink
herb
look
better.
B
C
A
Here
is
to
let
people
play
with
the
systems
they
synthesize
and
come
up
with,
and
you
know
how
our
community
works
so
great
to
say:
look
you
go
to
a
conference,
look
what
I
did
and
then
everybody
else
next
year
will
have
what
that
guy
had,
but
that
guy's
moved
on
to
mills
exactly
yeah,
so
it
is.
It
is
interesting
that
this
should
stimulate
a
lot
of
development
work,
just
because
it's
not
a
piece
of
cake.
A
B
A
D
D
D
A
B
A
A
Because,
as
you
see
as
you
get
closer
to
the
earth,
the
link
doesn't
necessarily
get
better,
but
you've
got
two
competing
factors.
The
the
beam
is
you
you're
rolling
off
more
on
the
beam
but
you're
getting
closer
to
the
earth,
so
the
the
signal
getting
is
getting
stronger
just
because
of
one
over
r
squared.
So
you
got
those
two
competing
factors
and
it's
not
entirely
intuitively
obvious.
C
A
A
D
A
D
A
One
thing
you
might
want
to
do
is
consider
beacons
here,
and
I
think,
maybe
because
the
word
beacon
has
been
so
so
confused
by
the
cubesat
community.
I
want
to
define
what
I
mean
by
beacon,
but
a
sub
carrier
that's
put
with
the
downlink
that
somebody
can
use
for
tuning
purposes
and
it
would
be
really
cool
if,
whatever
you
decide
for
the
uplink,
whatever
digital
channel
you
decide
could
have
a
mode
where
that
you
know
like
there's
an
alternating
1-0
pattern.
D
D
Yeah,
I
know
we
have
modes
where,
where
they
can
monitor
those
all
the
signal
parameters,
that's
done
routinely
because
when
it
starts
raining,
we're
going
to
have
to
they're
going
to
have
to
see
that
their
power
is
not
enough
and
they're
going
to
have
to
adjust
the
power
dynamically.
That's
going
to
happen
all
automatically.
B
B
Yeah
we
have
some
some
stuff-
that's
published
that
walks
through
the
the
basic
concepts
of
of
how
it
operates
and
someone
working
on
a
more
detailed
authentication,
authorization
that
the
loop,
the
acquisition
loop,
and
so
we
we
do
have
some
written
work
and
wally
is
going
to
really
take.
Take
that
base
that
we
that
we
have
that's
currently
published
and
really
bring
it
up
to
more
complete
level
here
in
the
very
near
future.
So
I
can
get
you
some
some
links
to
the
stuff.
B
B
B
B
A
A
A
A
D
D
D
A
D
D
B
A
Well,
I
mean
you
know
what
you
what
you'll
notice,
I'm
sure
before
this
is
over
is
there
will
be
portions
of
the
orbit,
which
favor
good
and
bad
conditions,
and
it's
it's
not
necessarily
driven
by
the
height
the
distance
from
apogee
either.
It's
because
of
the
the
you
know
the
first
first
nulls
of
the
antennas,
you'll
you'll,
probably
find
that
there
are.
A
There
are
spots
where,
on
average,
the
users
will
do
better
than
on
on
other
spots
on
the
orbit,
and
so
you
can
try
and
adjust
the
what
the
users
are
doing
at
those
times
based
on
that,
in
other
words,
there's
lots
of
games
to
be
played
here
and
and
while
they,
while
those
games,
couldn't
be
played.
If
you
were
professionally
doing
this,
where
you
have
to
assume
a
comm
link
is
presented
100
of
the
time
with
99.99
reliability,
we
don't
have
to
assume
that.
C
C
B
C
B
Items
written
down
here
and
I'm
sure
that
we
will
have
plenty
more
to
talk
about
and
catch
up
on.
This
has
been
absolutely
fantastic
and
what
I'll
do
is
I
will
edit
up
the
video
yeah.
This
is
exciting,
so
I
have
plenty
to
do
on
the
document
with
the
documents
you
sent
me
the
action
items
from
tonight
and
is
there
anything
else
that
I
can
do
to
help
make
this
make
this
great.