As of today those 3 APRS balloons launched in the UK are still flying after
more than 3 weeks!
Amazing.. One of them over alaska has gone round the world more than 1.5
times, the other two are over Japan and approaching 1.5 orbits.
If you can make a flight ready amateur payload with some kind of
educational association in the next 3 months, there is a ride. You get a
temperature controlled 0-60C flat plate about 4 by 7 and 28v power on the
outside of a large free-flyer. The bad news is that the mission is low LEO
so maybe
Actually, using simple pass-times, it is possible to predict with a simple
pencil, all future pass times for several weeks.
Every satelite REPEATs their daily ground track every few days or so.
AO51 repeated every 5 days, and GO32 every 9. These were sun synchronous
and so not only the ground
Can some explain to me and others the big deal about cube sats?
I just dont get it.
Standardization! But the real payoff from standardization is REDUCED RISK
to the launch provider. Instead of having to micromanage every detail of
satellite design so that the launch provider can GURARANTEE
That is why I want so much to continue the 145.825 digipeater on as many
satellites as we can*.
But we can’t seem to inspire any of the other HUNDREDS of satellite
building groups to consider it.
I think there were over 100 cubesats launched last year. None with 145.825
APRS…
*(and
Trevor,
The M0XER-4 (I thought) did frequency shifting (APRS 144 MHz national
channels over Europe and the US), and so I thought it had more complexity.
The image shown on the link below only has 434 MHz antennas, no obvious
GPS and no VHF antennas. Can you clarify and help us get an idea of
I heard part of something on the news about one of the victims of the
Aircraft shootdown in the Ukraine was a young Aerospace engineer working on
a design for a constellation of cubesats for low cost communication with
individuals on the ground.
Sounds like a HAMsat project to me. Anyone know
The biggest load in a communications satellite
is almost always the downlink RF power amplifier(s)...
True for some, not true for others. The locations of ham operators are
only about 10% of the earths surface. 90% of transmitter power can be
saved if the transmitter is not left on 100%
Regarding real LOW Earth “orbits”, G6UIM reports a Balloon launched in the
UK is approaching Washington state from across Asia and the Pacific right
now.
See: http://spacenear.us/tracker/ look for Balloon B-63
It is being well received by the APRS network in Canada, Washington and
Oregon as it
But if the goal of satellite operation is from the shack-potato position,
why not just use the internet and not bother.
Don't forget the TOTAL FAILURE of the original SAT-PHONE industry when
they ignored cellphones and fiber. No one would bother with a sat-phone
when their $9/mo cell phone could
/19/2014 09:23 PM, Robert Bruninga wrote:
I cannot believe that. The equilibrium of a nominally black (solar panels
on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a
very benign operational range. The only time you DO have thermal issues
is
when you DO have attitude
:59
Subject: Re: [amsat-bb] ANS-199 AMSAT News Service Special Bulletin -
AMSAT Fox-1C Launch Opportunity Announced
On 07/19/2014 09:23 PM, Robert Bruninga wrote:
I cannot believe that. The equilibrium of a nominally black (solar panels
on all sides) spacecraft is something like about 0
Karn k...@ka9q.net wrote:
On 07/19/2014 09:23 PM, Robert Bruninga wrote:
I cannot believe that. The equilibrium of a nominally black (solar
panels
on all sides) spacecraft is something like about 0 to 30 C (32F to 90F) a
very benign operational range. The only time you DO have thermal
The lack of attitude control forces us to use simple omnidirectional
antennas, which in turn keeps us on the crowded and narrow VHF/UHF
bands. Worse, there's really no such thing as an omnidirectional
antenna so our links are plagued by frequent deep fades of unlimited
(or at least unknown)
If anyone in Europe wants to submit a paper on APRS and other AX.25
satellite relay, this conference might be a good match. We like to think
of the 145.825 AMSATs as a continuum of remote-data access for student
experiments and remote data access…
-
IEEE Conference on
I have been asked by ICOM to webcast field day this year.
Unrelated, but it would be great if someone with a good satcom station
recorded the passband of FO29. Not so much to get individual QSO's but to
grasp what a full wideband transponder can carry.
IE, tune the passband from one end to the
A far less complex and easy to do transmitter hunt is simply bring along a
bunch of FRS radios. Put a rubber band and some aluminum foil around one
of them to key it and make it very low power (carrier only). With a range
only sufficent to barely cover the venue (weak signal at the starting
The beacon while-unattended into a very valuable limited channel such as
the ISS and PCSAT digipeaters are disappointing to me. The purpose of the
APRS digipeaters in space are for humans to contact humans, or for the rare
-out-in-the-atlantic or Pacific lone traveler or experiment.
The
Driving to Dayton:
For AMSAT guys, even if you don’t have an APRS radio, set an HT in your car
to 144.39 with CTCSS 100 and the speaker will be 100% quiet unless there is
an APRS mobile in simplex range, and then you will hear his CQ once a
minute. If you hear one, then he is in SIMPLEX range
Crowded Air space today over PA!
Saturday morning, launched the Naval Academy Balloon (W3ADO-11) from
Harpers FY and noticed two other balloons launched about the same time
(W3EAX-9 and 11) about 40 miles north. All was going fine until...
Our sincere apologies to MD, VA, PA, DE and NJ! At
deciding if I should buy a new AZ/EL rotator mine current one is 15yrs
old and dead.
For all current Amateur Satellites, elevation control is not needed 98% of
the time. If you are willing to give up the 2%, you can operate with a
manual $70 azimuth only TV rotator instead of a $500 full AZ/EL
have the payload intact, we may try again in the next
weeks or so.
Bob, WB4APR
*From:* Robert Bruninga [mailto:bruni...@usna.edu]
*Sent:* Monday, April 07, 2014 10:48 AM
*To:* aprs...@tapr.org; a...@yahoogroups.com
*Cc:* amsat-bb@amsat.org; k...@usna.edu
*Subject:* Balloon lost near Shrewsbury
Short Story. The balloon is lost near Shrewsbury, PA. But we are sure (now
after post processing) that we know where it is within about an acre.
See: http://aprs.org/balloons.html
Premature burst (or separation) caused the payload to descend at over 5000
feet per minute slowing to 4000'/min
Balloon chase Sunday morning, Southern PA:
Should hear it over all Midatantic states!
Our balloon will be launched near Chambersburg, PA 9 AM? and will fly
across southern PA landing somehwehre near Newark, DE.
It will fly faster than the launch team, so we hope other hams will get to
the
I cut the RFI Ferrite blobs off of all trash Keyboards and stuff.
These are great Ferrite devices.
But what are they best for?
Check out this article from Chuck Councilman W1HIS:
http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf
Wow, a long one, but on page 24 of 42 I
For what it's worth: PCSAT is still maintaining a 0.6 RPM spin about the Z
axis.
Today for fun, we commanded PCSAT and got 4 minutes of 10 second data.
During 100 seconds it completed 1 revolution which equates to 0.6 RPM, the
same rate as 13 years ago.
From that we conclude that our
I cut the RFI Ferrite blobs off of all trash Keyboards and stuff. These
are great Ferrite devices.
But what are they best for? IE, 1) are they intentionally lossy or are
they High Q? and 2) What is their Optimium Frequency range (all ferrite
torroid coil forms come in a variety of materials
Is that the zero degree horizon footprint or the more usual 10 degree
footprint?
Bob, Wb4aPR
On Sun, Mar 23, 2014 at 10:44 AM, Håkan Harrysson sm7...@telia.com wrote:
Hello!
If you want to see how footprint looks from 26 degrees east you can
have a look on Picture at
Need an AMSAT greybeard with attitude control experience.
We want to use only one magnetorguer coil (a Z coil) to more or less keep
our Z axis aligned with the Earth's axis (+/-30 deg)
We figure if we energize the Z coil only twice per orbit while over the
equator where the Earth's magnetic
...@8p6sm.net wrote:
On 02/08/2014 09:24 AM, Robert Bruninga wrote:
Any ham... to collect this content simply puts his 9600 bd radio
listing to that repeaer INPUT to join the net! An AP runs together
building a buffer of that 70 Mbytes of ham radio content per day, which
Already Ham Radio has the technology, bandwidth, and evreything needed to
implement distribution of over 70 megabytes of Ham Radio data to every
mobile and handheld operator every day. That's a lot of content.
And the frequencies exist, and the sites exist. THink about it. Every
single VOICE
Sure would had liked advanced notice on this.
A project we would have enjoyed doing.
I have some students planning a possible launch in Northern VA sometime
this coming weekend. Probably Saturday. Wont know details until the day
before. Intent is to predict the path the morning of, and then
Balloon near Richomnd headed east at 60 MPH. See it on
http://aprs.fi/k4wcu-11 and copy it on 144.39 APRS. I'm hearing it direct
over 170 miles away in Baltimore.
-- Forwarded message --
From: PaulY p...@mtnlist.com
Date: Sat, Feb 1, 2014 at 1:30 PM
Subject: [APRS] URGENT HELP
Has anyone had any experience with any success at DTMF working on HF for
some rudimentary commands?
I know tuning is critical as well as inter-tone noise must be way down.
Just thought maybe someone has experimented with it.
Bob, WB4aPR
___
Sent
I think the QFH throws most of the energy straight up (broad pattern,
but not a lot at the low elevation angles).
Or another way to look at it, is that satellites at low elevations angles
are 10 dB farther away so they will always be weaker by a factor of 10 to
1 to high elevations.
Bob, WB4APR
The satellite is only in transponder mode when it is in eclipse..
In full sunlight it is in beacon mode only.
Just curious about the overall design goals of this operating mode?
Putting solar energy into and then taking it out of batteries suffers
about a 30% loss in efficiency. All else being
Yes, that was UO-11 Comes back to life every now and then and has a LOUD
downlink on 145.825 but it is not AX.25 packet.
Bob, WB4APR
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Dave Marthouse
Sent: Friday, December 20, 2013 11:39
... asking Bob to comment on his earlier thoughts on using antennae at
fixed elevations?
The geometry of LEO satellites has not changed. The optimum angle for a
fixed tilt modest gain YAGI is about 15 degrees (assuming you have a
decent horizon). See:
http://aprs.org/LEO-tracking.html
That
To follow up on Bob's comment. If you send the raw analog sensor
data...
Change calibration values if found to be wrong after launch...
We did on PCSAT!
Caution to Satellite Builders: Be careful when using an EXCEL TREND LINE
equation for doing Engineering Unit conversion back to original
Answer: Engineering efficiency..
There is far more computing power on the ground than the satellite. Also,
KISS principle. Also, calibration can be done without modifying flight
code. And finally, it is far more compact to send binary or hex than
human readable decimal.
Bob, WB4aPR
Nothing heard from DragonSat on 145.870. (9600 baud AX.25)
A crude test of a Dragonsat model with the antenna un-released was still
radiating on the order of 26 to 36 dB down.
From now on, instead of FM, we are going to listen with an SSB receiver
and see if we hear the 30 second chirps.
EZnec kibitzers welcome:
See this model image: http://aprs.org/psat/VHF-circ-tuned-ask.gif
We are placing two ¼ wave VHF whip antennas on a single feed at the corner
of a 1.5U cubesat.
We want them +/-45 degrees out of phase so that we get cross polarization
when paralleled to a single
OOPS, One error I made is confusing R+j45 ohms as “45 degrees”, when +45
degrees is really R+jR… Right? So I am now starting over. Ignore my post
until I fix it and repost the results.
Bob
---
EZnec kibitzers welcome:
See this
EZnec kibitzers welcome: (corrected version)
See this model image: http://aprs.org/psat/VHF-circ-tuned-ask.gif
We are placing two ¼ wave VHF whip antennas on a single feed at the corner
of a 1.5U cubesat.
We want them +/-45 degrees out of phase so that we get cross polarization
when
At 1748z today 26 Nov, in Maryland, I heard what sounded like a solid
carrier on 145.825 Cape frequency with clear spin modulation. It was
right on schedule with the other Wallops launch birds. Like I said,
sounded like a carrier only, so the spin modulation of the antenna was very
obvious.
Ø When there is a launch of several satellites in a single payload,
several cubesats for example, I assume they release each at
different locations on the deployer trajectory. Preliminary keps are based
on the trajectory when each is released?
Ø Otherwise if they were released all at once,
The following link is of Picodragon and 2 other satellites
being released from ISS. There is a picture and short video.
http://amsat-uk.org/tag/picodragon/
Looking at the video, my uncalibrated eyeball counts the deployment rate at
about ½ meter per second? Ie, in the first second of
We are hearing some interesting things from CAPE, one of the Cubesats from
Wallops. We are hearing 1 minute AX.25 telemetry, and we have heard two
Voice tests, and it has a CW message. All three modes in a Cubesat and on
the APRS 145.825 downlink... neat. The voice might be DSB? And we are
Watch for a dozen new cubesats Tuesday from Wallops at about 7:30 PM.
I have seen a lot of email about Funcube, but haven’t seen much about the
Wallops launch.
All of them downlink on 435 MHz band except for Naval Academy downlinkning
on 145.870.
Seven downlinks are at 9600 baud, one at
--
On Mon, Nov 18, 2013 at 4:25 PM, Robert Bruninga bruni...@usna.edu wrote:
Watch for a dozen new cubesats Tuesday from Wallops at about 7:30 PM.
I have seen a lot of email about Funcube, but haven’t seen much about the
Wallops launch.
All of them downlink on 435 MHz band
A fellow came to me convinced that capturing RF energy from cell phones,
and radio and TV waves was free energy. He couldn’t wait to invest in
these pocket sized antennas that have achieved the same 37% energy
reception efficiencies as do the most expensive solar cells:.
Why don’t we see simple ¼ wave 75 ohm lines used as a first step in
matching a 140 Ohm Helix to 50 ohms?
The ¼ wave line would give an easy 112 ohms and then it shouldn’t be that
hard to do a little additional construction matching to get to 140?
(building a 2.4 GHz pop-out helix that
When the Earth image is about 4 across (8,000km), and the satellites are
one pixel across (say .001) then each dot is actually to scale a
spacecraft that is 8km wide. Which is about 8000 times bigger in diameter
than a real spacecraft.
So what you are seeing is what space would look like if
OOPS... Corrected...
---
When the Earth image is about 4 across (8,000km), and the satellites are
one pixel across (say .001) then each dot is actually to scale a
spacecraft that is 2km wide. Which is about 4000 times bigger in diameter
than a real spacecraft.
So what you are
If someone will build a linear PSK-31 transponder, I have a launch
opportunity in 9 months.
All it needs to be is a PSK31 Linear receiver on 28.120 MHz (3 KHz
bandwidth) with AGC coupled to a downlink UHF FM transmitter of about 1
Watt. Should fit on a 3.5 square card. This is the same as Brno
As long as AMSAT-NA needs to concentrate on... Cubesats...
I would really like to see the pursuit of linear transponders...
on them instead of single-channel FM repeaters.
We can have the best of BOTH FM and Linear!
But we used to use a ucc1 in the navy to receive messages.
Amen,
Just go to the biggest SmallSat conference on earth at the annual AIAA/USU
conference in Utah. Unlike AMSAT, the registration is $600 each, and it
lasts 6 days and all 500 to 1000 attendees are fully into Small Cubesat
like missions. And very expensive instruments. Every space related
APRS has standardized an ID series for amateur Oscar spacecraft. APOxxx.
At the request of Juan Carlos, LU9DO, AMSAT-LUwanted a series of APRS
designators for uniquely identifying AMSAT APRS applications. He
suggested those beginning with the letter O for OSCARS.
ALL APRS applications include
Just to clarify, the time tracking works just as well for the
elevation rotor. You can see my balloon chasing 2.4 GHz antenna on my
van here: http://aprs.org/balloons.html about 1/3rd down the page
(the second balloon mission). But it used a full Yaesu AZ/EL system
so I did have feedback.
My
These motors run at a nearly constant rate. ALl you have to do to
know position is to keep track of the time they are on. It remains
calibated because at the end of every pass (it ends at zero elevation)
so you konw you are at 0 (include say a 10% overshoot after the pass
to be sure it is at 0).
Given the classic 1/2 wave cavity filter, what is the relationship
between inner cavity and center conductor sizes? Of course bigger is
better, but what is OK.
This is a 1/2 wavelength tube with a center conductor shorted at each
end. The input is loop coupled at one end, an output is loop
CAPE-2 ... [is] planning to fly a digipeater...
I am currently developing software to distribute to you guys
later this year that will copy our telemetry and have it automatically
sent back to us.
I hope your telemetry is APRS compatible so that it can also be
distributed by the global
Solar Impulse flying up Jersey Coast NOW (9 AM Saturday).
Need an APRS operator to watch position on
http://live.solarimpulse.com/ and then maintain an active object on
APRS RF so that all mobiles can see the aircraft on their mobile
radios and be able to lookup and see it.
Its the size of a 747
,
WB4APR
*From:* Robert Bruninga [mailto:bruni...@usna.edu]
*Sent:* Tuesday, July 02, 2013 11:32 PM
*To:* amsat-bb@amsat.org; aprs...@tapr.org; a...@yahoogroups.com
*Cc:* bruni...@usna.edu
*Subject:* Golden Packet 20 July gaps: NH, MA, NY, NC/TN
We have an urgent need for Ham Packet Ops on mountain
WHy only those 3 radios?
Cannot any 2m rig with any [TNC] or one of their other devices, or even
a venerable kpc3+, digipeat?
Yes, but it is all about risk. Generallly, 90% of all packet radio/TNC's
on the air are misconfigured in someway or another. It has been this way
for the last 40 years
We have an urgent need for Ham Packet Ops on mountain tops in New
Hampshire, Mount Greylock, MA, Sams Point, NY, Clingmans Dome in the Smokie
Mountains and Roan Mountain NC.
This is a 4 hour event making our annual attempt at the Golden Packet, an
APRS packet message from Maine to Georgia along
A Sub orbital launch from Wallops Island..
some of you... with high gain 2 meter antennas and possibly elevation control
(depending on where you are- approx 70 miles elevation at apogee) will give a
listen for it
Assuming the ground track is out to sea for range safety, then I would
assume
Solar Powered flight is underway from Dallas to St. Louis. See the flight.
http://live.solarimpulse.com/
We need APRS operators in RF range to help maintain an OBJECT track on the
bird so that not just those in front of a PC can see this, but also those hams
in their APRS mobiles who will
The nicest configuration... would be a 2m FM uplink with CTCSS to avoid
interference and a SSB 10m downlink.
The problem with that is the same as all our other FM satellites. Only a
single user at a time. Congestion, conflict and little practical value.
The better use of SSB is to use the
if there were a real ham on the ISS things would be different.
Yep, then nothing would get done. All he would do is float around and
complain about all the things that everyone else should be doing.
Bob, WB4APR
___
Sent via AMSAT-BB@amsat.org.
I found my old web page with graphics that shows the exact geometry of
passes and elevations.
See http://aprs.org/LEO-tracking.html 70% of all pass times are below 22
degrees.
After the discussion a few weeks ago, I sat down today to begin building a
web page on the topic and when I went to
are also
on the horizon?
On 5/13/2013 11:29 AM, Robert Bruninga wrote:
As has been said many times, most satellite passes are never
directly overhead, but rather on some inclination across the sky.
A 5 element yagi antenna, at a 35 degree angle from the horizon,
with only an asmuth rotator
One needs to also realize duration. The time say above 70 degree
elevation (where rates are highest) are less than 2% of the total pass
times. Not worth worrying about. Similarly, a LEO satellite spends 70%
of its time below about 22 degrees. (but it is far away and needs max
gain). So simply
As has been said many times, most satellite passes are never
directly overhead, but rather on some inclination across the sky.
A 5 element yagi antenna, at a 35 degree angle from the horizon,
with only an asmuth rotator, will let you work far more satellites for
the money spent.
Except that
The antenna, that I want to build, is described in a paper (probably 20
years old)
by Dick, WD4FAB, titled 'Antennas for microsat ground stations', and the
paper
describes the large time, a LEO remains at low elevations - about 76 %
below 20 degrees -
and then concludes, that this is fine for
Going from 310 to 700km in a year is not doing us anything.
Im not following this closely, but that statement misses the most
important reason for doing this...
*to*stay*in*orbit!
The lifetime of a cubesat at 310km is only a few weeks at most. The life
time at 700km is tens of years.
The
... which is going to be the best type of antenna...
to receive the 145MHz downlink signals
There are lots of good hemispherical satellite antennas that provide equal
gain for all satellites in view. However, these designs ignore the fact
that satellites on the horizon (LEO passes spend almost
LES1 (I think) has a bent-pipe transponder for military UHF (250 MHz
area). I wonder if the billion to one chance that the transponder came on
too?
Bob, WB4aPR
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of Alan
Sent: Wednesday,
I wonder what 435kw at 28,000 km will do to the surface temperature on
that rock?
Let's see, power goes down as 1/R squared. So lets compare it to a
candle. A candle is about 50 Watts or about (435000/50W) or about 10,000
times less power. Take the square root of that to get about 100/th the
:* Robert Bruninga [mailto:bruni...@usna.edu]
*Sent:* Thursday, January 31, 2013 10:53 AM
*To:* amsat-bb@amsat.org
*Cc:* aprs...@tapr.org; a...@yahoogroups.com; bruni...@usna.edu
*Subject:* QRT all PCSAT transmissions!
Please QRT all transmissions to PCsat to save power for COMMANDing.
PCSAT
,what kind of battery is install on this kind of satellite?
how does it react in the cold space where it is?
We placed the batteries in the middle of the satellite. It is quite
immune to the +90C and -100C possible fluctuations on (unattached) solar
panels (if they were not attached to the
Please QRT all transmissions to PCsat to save power for COMMANDing.
PCSAT (W3ADO-1) is entering its 3 day RECOVERY window this year starting 31
Jan.
Today we got logged on for commanding twice, but both times user packets
killed the bird.
At best PCSAT can usually only save up enough
Please let me know what you miss the most (via amsat-bb or directly) and
I will attempt move it higher on the priority list.
This week (thursday) I have about 30 students doing the one-day satellite
tracking lab. The lab document calls for them to look at their selected
satellite on the AMSAT
Help me delete the dead satellites.
Help me add new Bleepsats.
We use this list in our Comms Labs for students to try to tune in:
* marks the operational ones from http://oscar.dcarr.org/index.php
? marks the unknown and need input from you.
* 07530 AO7 145.950
? 20442 LO19
where is the contact?
that just shows that both were able to copy each other.
But they exchanged a QSL and both got the original exchange info from each
other.
On a shared single channel resource, we should be concerned with contact
efficiency.
This takes 16 packets for 8x8 or a total of 64
For any AMSAT folks have TH-D72’s:
We are looking for as many D72 owners that live within a few hours of
Mammoth Cave, KY to join in a significant cave-radio experiment on 2-3
March 2013 to demonstrate VHF/UHF cave radio “texting” and status
reporting. The D72’s can automatically relay
KJ4ERJ's satserver will send you live tracking data to your APRS radio
anywhere, anytime.
Just send an APRS message to ISS from any APRS radio (on the national
APRS channel) and if you are in range of the global APRS network (an
IGate nearby), then it will respond with the time to AOS and the
And where on the planet might this local event be? A balloon can have a
range of 400 miles or so. Lots of us can watch if we know what part of
the planet this might be in...
-Original Message-
From: amsat-bb-boun...@amsat.org [mailto:amsat-bb-boun...@amsat.org] On
Behalf Of David Julian
Use your APRS radio for global contacts at your JOTA station.
You can use your APRS radio or HT to text message a CQ to all other JOTA
stations with an APRS radio anywhere in the world. You need to remember
nothing about the network, or paths, or freqs or do any set up. Just use
the normal APRS
Wow, a narrow self centric view of the world:
a huge trend to build more and more of these shoe boxes..
... most of them are almost useless...
What kind of science is it,...
The wheels are re-invented again and again...
For us AMSAT'ers.. this is something we did almost 30 years ago
the record breaking skydive mission is currently in
progress. tune to: http://www.redbullstratos.com
Also tracking an object on APRS called STRTOS-11.
See http://aprs.fi/strtos-11
___
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the
Does Anyone know what the APRS tracking ID for the Red Bull Stratos Balloon
Track STRTOS and STRTOS-11
I was surprised that no one else was inputting objects, so I fired up
my old 486 laptop which has not been used in years and initially
enetered the STRTOS object. Then killed it to change to
I presume the reason for UHF downlink rather than
145 MHz, with it's lower Doppler shift, is due to
other mission constraints ?
Yes, avoid QRM to the 145.825 APRS transponder.
BTW is the uplink in the amateur satellite segment
of 10m (29.3-29.5) or down at the bottom of the band ?
Bottom
The ideal AMSAT FM transponder for a cubesat is the PSK-31 transponder
being developed for the Naval Academy PSAT mission.
With an FM downlink, anyone can receive it with an HT and a laptop with
PSK-31 software. And anyone with a 10m PSK-31 uplink can transmit to it.
The reason it is ideal is
Although there are a few APRS type Balloon launches every few months to
serve as educational tools and short-duration small-satellite simulations,
there is often not one available when you happen to need to show some
students a class.
Now, a Ham in Brazil has written a sound-card decoder for the
I'd say that differently...
Nothing wrong with using the camera. But your point is well taken to
calibrate the camera to the BEAM by first pointing at the sun. Then (if
your camera survives) the camera is a perfectly good aiming device for the
moon and it eliminates any errors in the Antenna
Assume a cubesat with a monopole ¼ wave antenna at 400 mhz.
The satellite is in full sun with a 500km orbit. What is the antenna
temperature in full sun and in eclipse?
It depends entirely on its color (surface properties). If it black it will
get to about 55 farenheight in the sun and to
Just heard ISS back on 145.825.
Two students went outside with a D7 HT and sent themselves email using
APRS via ISS. Came back inside and were amazed to see the Email in their
inbox already!
Now they understand APRS!
Bob, Wb4APR
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Argent Data makes a small SSTV camera about 1.5 cube for under $100. For
all practical purposes it is a modern replacement for the original Kenwood
VC-H1 SSTV handheld. He makes them for balloons etc.
We have one on a model satellite hanging out in our lobby and anyone can
trigger it with any
IO-26 is still up there, and still humming;
But we haven't figured out how to run it in
voice like we did with AO-16;
Woha! But if it is a pacsat, can't it act as a digipeater if you just set
the DIGI bit to on? Then people can use it for real-time digital QSO's.
In the old days, it
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