June 30th, 2008 UTC
The AO-27 Control Operators Assoc. D-Star Repeaters are on the air:
N4USI Port C 145.45-
N4USI Port B 442.4125+
They are located in Haymarket, VA
June 29th, 2008 UTC
A New Schedule has been uploaded.
March 8th, 2008 UTC
A New Schedule has been uploaded.
September 15th, 2007 UTC
New Schedule has been uploaded.
June 28th, 2007 UTC
New Schedule was uploaded before field day on the 23rd. Batteries are looking fine for their age.
April 14th, 2007 UTC
We are moving the Web site. Please bear with us as we move.
Some links may be down until nameservice is finished updating.
February 3rd, 2007 UTC
AO-27 is back to a normal schedule. But I am leaving the on-time up at 7
January 31th, 2007 UTC
Allen, N5AFV is working from Honduras, Belize, Cozemel and from sea.
For the next few days, the schedule is shifted 7 minutes early but is
extended to 8 minutes ontime. The web site has the correct times.
Thanks you Allen for the contact from V31 land.
Also of interest is that N1XAU was heard on a pass today.
Its good to hear Bridget (for those that don't know, she is my mother) back
on the air. Keep an ear out for her call.
- Michael, N3UC, AO-27 Control Operator
January 14th, 2007 UTC
Well, we received the information we needed on this last pass. So the TOPR
schedule is now running. Please see the Schedule above for times.
January 14th, 2007 UTC
After working on serveral problems with the AFSK modem on AO-27, we have
been able to upload the flight code. AO-27 is now running the EOS software
and sending good telemetry. Batteries are lower than we would like but we
have been hitting them very hard this weekend to get the code uploaded.
As soon as we have finished checking out the bird we should have the
Analogue repeater back on the air. Please keep in mind that AO-27 is 13
years old and takes some work to keep it going.
January 6th, 2007 UTC
We have successfully reset the cpu on AO-27.
AO-27 is now commanable and is sitting at the bootloader. We are
beginning the process of uploading flight software. The transmitter was
very strong during our tests. This is very good news.
December 28th, 2006 UTC
We still have not been able to turn on AO-27. We are now ready to try
another method to get control. Please keep your fingers crossed.
October 17th, 2006 UTC
For the last 5 weeks ground controllers have been trying to contact AO-27. At
this point we have not been able to turn it on. We still have a few
tricks that we are planning on trying but these take time. We are hoping
that we can re-establish communications.
At this time, we don't have an estimate for when AO-27 will be back on the
AO-27 is now in its 14th year on orbit. We will continue to try to recover
AO-27 until we run out of ideas.
May 15th, 2006 UTC
AO-27 is in eclipse season. This means the batteries are dropping below the
watchdog values and turning off the schedule. I need to reset it each time
it happens. Everyone that has watched AO-27 go thru this period before
should remember this procedure. This is not an indication that AO-27 is
approaching end of life. It has been running this way for years. Please be
patient until we get back into full sun.
AO-27 takes a bunch of work to keep flying. We are comming up on 13 years on
orbit in September, well past what any of us expected when we launched it.
Happy Birthday Jimmy.
April 29th, 2006 UTC
New schedule. Bird is back on.
Feb 18th, 2006 UTC
A new schedule has been uploaded.
We have been busy this last week tracking and recording SUITSAT. Thanks to
the SUITSAT team for a ton of fun.
Oct 10th, 2005 UTC
A new schedule has been uploaded and TOPR is running.
If you listen during the Data mode, you will hear that telemetry is comming
down. So far, everything looks good with this upload.
Oct 8th, 2005 UTC
Even better news today. Uploading of Flight Code finished on the 5th pass
tonight. It is running and telemetry is comming down.
I hope to finish the on-orbit check out of the flight code in the next few
days. Then I can turn back on the analogue repeater. Please keep your
fingers crossed that the code stays in one piece this time.
Oct 7th, 2005 UTC
Great News. After a lot of revisiting of the FireCodes, we have been able
to reset AO27. It now sits at the bootloader. If all goes well, we should
have the flight code back up this weekend.
- Michael, N3UC
Sept 29th, 2005 UTC
A new schedule has been uploaded and seems to be working. The Website times
are once again correct. We are still working on resetting the CPU so we can
upload a clean copy of the flight software.
Sept 26th, 2005 UTC
AO-27 is now in it's 13th Year on orbit. Although we are still having
commanding problems, the transmitter sounds good. The command team is
working on tring to reset the satellite so we can reupload the flight code.
We hope that will correct the commanding and telemetry problems.
Aug 26th, 2005 UTC
Times are off on the satellite by about 3 minutes. Commands to reset the
time and schedule are not working. We are working on the problem.
May 18th, 2005 UTC
I have placed a new schedule on-board but the Orbital Time from the
satellite seems to be about two minutes early compared to the website and my
control software. I really need any reports of on-off times. Try to get as
close to the second as you can and make sure your clock is calibrated closly
to GPS or some other time source. Please let me know how good you think
your clock is. Times in UTC will help.
I have lowered the watchdogs so I hope the on times will be longer but
with the current way the satellite is timming I don't know for sure.
May 16th, 2005 UTC
Our latest attempts to get software and schedule status downloading did not
go well. Whole orbit data downloading has also been affected by what ever
has caused the status problems. Right now we are not receiving enough Whole
orbit data to determine the status of the batteries. The on times of the
schedule are not what they should be. While watching the real time
telemetry this morning, I noticed that the batteries were at a good level
but the watchdog code turned off the transmitter early. It it posible that
what ever has corrupted the status and WOD downloads has also affected the
Any reports of timing (both on times and off times, of both Analogue and
Digital) would be helpfull.
They can be sent to firstname.lastname@example.org. Thanks.
May 15th, 2005 UTC
On-orbit check out continues but I have put the schedule into Analogue mode
for some of the pass. We have lost software and schedule Telemetry downloads
and we are looking into the cause. We have a new watchdog looking at the
batteries. If the satellite turns off early, the batteries might be low.
The last version of the software would just stop the schedule, this one will
let it continue unless the batteries get too low.
Happy Birthday Jimmy.
Everyone have Fun at Dayton.
April 14th, 2005 UTC
Flight Software is now running on AO-27. The watchdogs have been changed to
keep better tabs on the state of the batteries. We are performing on-orbit
checkout and we hope the Analogue repeater will be back in operation soon.
Right now, the schedule is running and downloading telemetry. If you have a
1200 baud AFSK TNC and can receive the data please help us by downloading
the software and sending us the data files. See the link about about
April 11th, 2005 UTC
Today marks the 3rd year on-line for AO27.ORG.
April 10th, 2005 UTC
After nearly two weeks of trying, control-operators for AO-27 were finally
able to issue commands to AO-27. The satellite is now running off the
boot loader that is programmed in to the ROM. In this mode analogue
operations is not possible. The first attempts to upload flight software
ran into problems. We are evaluating the logs from the attempts and are
tryng to work out a plan for uploading the flight software.
The uploading of the flight software is not something that has had to be
done much in the life of AO-27. It was last uploaded in March 2003 to
switch to the TOPR way of scheduling. Before that it was uploaded in Sept
2000 after the satellite rebooted for unknown causes. The upload before
that one was in December of 1993. Only 3 uploads have been done in the last
It will take some time and a lot of work to get it back to operation status.
We can't answer any questions as to when it will be back in operation.
March 24th, 2005 UTC
The Scheduler has gone into recovery mode. The transmitter will be off
until the batteries are recharged.
Jan 20th, 2005 UTC
A bug was found that was keeping the ground station from posting the updated
schedule on the website. The website should now have the correct TOPR
Jan 5th, 2005 UTC
A new schedule has been uploaded and the onboard clock has been reset.
Aug 6th, 2004 UTC
A new schedule has been uploaded. If the batteries hold then it should
continue to run. If the batteries get too low then the software will turn
the schedule off and we will have to compute another one.
June 26th, 2004 UTC
We plan to have the bird on for Field day. We will try to have a schedule
uploaded but we will at least turn it on when in view of a command station.
May 17th, 2004 UTC
We are back in eclipse season and the batteries are low. We will have it
back on once they charge back up.
April 18th, 2004 UTC
New schedule has been uploaded. Web site time should be correct again.
February 8th, 2004 UTC
New schedule has been uploaded.
February 6th, 2004 UTC
The on-board watchdogs have turned the scheduler off. This was expected as
the last few days of telemetry have shown lower battery voltages. We will
be downloading the Whole Orbit Data and looking at why the voltage is lower.
I will send a new schedule up as soon as we know what happened. Keep in
mind that AO-27 is in its 11th year on orbit. If you hear the telemetry,
please don't try to uplink, you will only cause interference to the command
January 22th, 2004 UTC
N5AFV is in EL-70 and EL-60 tonight. He is using just a whip antenna on a handheld
due to problems with his beam that he took with him. But even with just a
whip he is able to make two-way contacts from these grid squares. Way to go Allen.
January 21th, 2004 UTC
Allen was on SO-50 from EL-83 this morning and on AO-27 from EL-71 tonight.
Some users are still stepping on him when he comes back to calls. Please,
if you hear someone calling him, give him a chance to respond. We don't get
a chance to work these grid squares often.
January 20th, 2004 UTC
Allen, N5AFV was heard from EL-65 during last nights passes. He will be on
from a cruse ship all week. I would ask that if you hear him please don't
step on his signal. He does not have much uplink power and many stations
would like to work the grid squares he will be working from.
Try to let him finish with one station before you give him a call so he can work as many
stations as possible.
- Michael N3UC
January 17th, 2004 UTC
The Analogue Time has been extended to 9 minutes. There is now also a 20
second digital download on right before the Analogue. This will let people
know when the bird is about to turn on. Total Transmitter On Time is now
11:20 per orbit.
Good luck to Allen, N5AFV on his trip. We hope to work him marine mobile via AO27
over the next week. Look for him on the bird January 19th to the 24th.
January 10th, 2004 UTC
A New Schedule has been uploaded. The analogue repeater is now on for 8
minutes. Followed by one minute of Telemetry download.
January 7th, 2004 UTC
The new TOPR Schedule seems to be regulating the batteries very well. I
have added a program to the website to calculate when AO-27 will turn on.
You can see the current state, when the next event will happen, and list the
next 24hr worth of events. Check back to www.ao27.org for all the current
information on the schedule. You may need to have your broswer refresh the
page to get an updated listing. The website recalculates the information
each time the page is loaded.
December 29th, 2003 UTC
After finding several bugs in the on-board schedule state machine, we have
managed to upload a new schedule to AO-27.
AO-27 will turn on for 1 minute of digital telemetry download followed by 6
minutes of analogue repeater operation in the evening passes. When we have a better understanding
of the battery condition, we will increase the Analogue time.
The schedule is started 3.5 minutes before the sub-satellite point crosses
Latitude 39.0N on an ascending pass.
It will also have a 1 minute digital telemetry download in the morning
starting when it crosses Latitude 39.0N on a decending pass.
April 15th, 2003 UTC
We had to turn the scheduler off due to problems observed on several passes.
April 5th, 2003 UTC
We have turn on the Scheduler. Weekend morning passes will be on for 10
minutes every pass. During the week it will be on digital mode.
March 15th, 2003 UTC
New software has been uploaded successfully to AO-27. The new commands are
working great and ON-ORBIT checkout is continuing. During the upcomming
week control operators will be checking out the new scheduler and fine
tuning the scheduler parameters. We will be turning on the Analogue
Repeater for time to time during this checkout period when we don't need to collect telmetry.
If all continues to go well, we will be able to turn AO-27 back to Normal,
self scheduled operations in a few weeks.
Thanks goes out to N1UC and W4XP for their tremendous effort in getting this
new software up to the bird.
March 13th, 2003 UTC
We will be rebooting AO-27 on Friday March 14. This will keep us from
turning on the Analogue Repeater until we have the new software uploaded and
running. Please don't transmit to AO-27 until we have the code uploaded.
Feb 14th, 2003 UTC
We have new software running on the ground CPU and are checking out that the
new scheduler is working. We hope to have the software uploaded to AO-27
next weekend. After the software is uploaded, there will be a period of
on-orbit checkout before we can turn the satellite over to operational use.
A special thanks goes out to our new control operator Chuck - W4XP for
helping us get AO-27 back in shape.
Jan 7nd, 2003 UTC
AO-27 is not running the TEPR states. All data from the satellite shows
that it is not entering an eclipse. This is causing the software to remain
in TEPR 6. Until we get this worked out, AO-27 will only be turned on by
ground station command and will have to remain in Digital mode.
The good news to all this is that the batteries seem fully charged.
AO-27's orbit has moved the satellite into a period of Full Orbit
Solar Illumination. Due to this, the TEPR method of timing the Transmitter
does not work. Therefore AO-27 can not turn its transmitter on by itself
and can only be turned on by ground station command. We will try to turn it
on for analogue work on the weekends when we are not downloading telemetry.
We are working on new flight software that will let us upload a schedule for
the transmitter. This will take us sometime to write, debug, and upload to
AO-27. Please help us by being paitient during this process. E-mail about
when the satellite will be on will just slow us down. We are working
quickly but carefully to get AO-27 back in analogue mode.
As a bonus to this orbit, during the seasons of Full Orbit Solar
Illumination, we will be able to have the transmitter on at night and for
different parts of the world.
Jan 4nd, 2003 UTC
The Tepr states have been reprogrammed for more normal operations insted of
the battery saving mode that we have been running in for the last few
months. As of Jan 3rd, the Batteries are looking good.
Oct 4nd, 2002 UTC
AO-27 is in Digital Mode. OnTime has been extened to 10 Minutes...
Oct 2nd, 2002 UTC
AO-27 is in Digital Mode. We in the process of moving the on time to 10
minutes and hope to have the satellite back in Analogue mode by the weekend.
Sept 16th, 2002 UTC
AO-27 is in Analogue mode for 8 Minutes. Please feel free to make contacts.
Sept 12th, 2002 UTC
AO-27 is back in TLM mode to check out how the batteries faired in analogue
mode over the week end. After several days, we will be increasing the on
time to 8 minutes and continue in digital mode until we have a good baseline
of battery voltages at 8 minutes. We will then turn back on the analogue
repeater for several more days. This cycle should continue until we find a
good maximum on-time for the batteries.
Sept 7th, 2002 UTC
We have turned on the Analogue Repeater to check the Current Drain on the
batteries while it is on. We plan to turn it back to digital mode on the
11th but the plans may change. This pattern of several days of digital mode
followed by several days of Analogue Repeater mode will continue until we
have a good feeling of how the batteries are reacting to the longer on
times. The last TLM data collected showed that batteries stable at an EOE
of 112 counts. (EOE = end of eclipse battery voltage, this is the lowest
point in the orbit that the batteries should reach)
Aug 29th, 2002 UTC
The TEPR state table is available in XML format from the web site. It can
be used as a source of input into programs or databases. The format should
be easy to understand if you know XML. Note to programmers, feel free to access this link in
tracking programs if you would like to include to most up to date
information on AO-27 in your programs. We update this file anytime we
reprogram the satellite.
XML Formatted Tepr Table: tepr.xml
XSL Style Sheet used to generate the HTML Table below: tepr.xsl
Aug 27th, 2002 UTC
The batteries are indeed comming back to life. There is still along way to
go but we are making progress. The transmitter is turned back on for 6
minutes every orbit and we need to collect Telemetry over the next few weeks
to make sure they are stable. We will then start increasing the on time
until we reach a good stable point. At that time, we can look into turning
the Analogue repeater back on.
July 22th, 2002 UTC
The batteries are starting to show a positive charge. We will be turning
the automatic data downloads back on. Check the TEPR schedule for
infomation on when the downloads are on. We still need people to monitor
and download the telemetry.
June 14th, 2002 UTC
The Batteries continue to refuse to charge up. They continue to show the
same low voltage as they did after the weekend of analogue repeater use. We
are downloading telemetry on weekends and continue to look for a solution.
There is not a schedule in place right now for when the satellite will
return to normal use.
May 20th, 2002 UTC
The Battery Voltage has pushed lower after this weekend of analogue repeater
useage. I had to turn off the 4 minute TLM dump that was happening every
pass. Right now, only when I get a chance to turn the transmitter on
manualy will there be data to copy. I hope the batteries will recharge back
to their memory charge level quickly so I can turn back on the daliy dump.
May 20th, 2002 UTC
The transmitter is back in Digital mode.
May 17th, 2002
The FM REPEATER is turned back on for the weekend. I will try to
turn the transmitter on longer during Saturday and Sunday mornings. Please
see the TEPR States for the on times.
May 16th, 2002
The new Domain name is up and running. You can reach this page at
May 15th, 2002
During many nighttime passes that are visible to the east coast, AO-27's
transmitter is turned on by command of the control station. The telemetry
that is sent down can be received by using a normal 1200 Baud AFSK modem and
the program AO-27TLM that can be downloaded from the TLM Page.
May 14th, 2002
Keep an ear out for the FM Repeater on AO-27 during May 18th and 19th. If
the batteries permit, we will be turning on the repeater on for Dayton.
May 11th, 2002
New Telemetry plots are on the Site. These were downloaded today and show
the current state of the battery voltage and the temperature of the bottom