Recap of EOSS-126

photo by Glenn Hetchler, WB0DKT

EOSS-126 up, up and finally ... away

LAUNCH DATE: February 23, 2008
LAUNCH TIME: 07:48 MST (14:48 UTC)
LAUNCH SITE: Windsor, CO (directions)

Pre-flight Prediction and Actual Track

Blue = Actual Track
Green = Predicted Ascent Phase
Red = Predicted Descent Phase

Map made with MapPoint
Prediction made with Balloon Track


Green Track = Ascent
Red Track = Descent
Prediction and Actual tracks made with Balloon Track

Maps by Google Earth

Map files available in the data section

Launch Site - Windsor
Launch Point: 40.47367� lat.   -104.96233� long.
Grid: X=2.62 Y=50.57
Ascent Rate: 1400 feet per minute
Descent Rate: 950 feet per minute
Altitude: 4931 feet
Predicted Landing Site
Landing Point: 40.56201� lat.  -104.52562� long.
Grid: X=25.5 Y=56.7
Altitude: 4500 feet
Flight Time: 128 Minutes
Bearing: 75.0� True
Range: 23.7 Mi.
Actual Landing Site
Landing Point: 40.52869� lat.  -104.64885� long.
Grid: X=19.1 Y=54.4
Bearing: 76.9� True
Range: 16.889 Mi.
Difference from Predicted to Actual Landing Site
Bearing: 250.5� True
Range: 6.864 Mi.


W0WYX Track and Landing Map

Blue = Actual Track
Green = Predicted Ascent Phase
Red = Predicted Descent Phase

Map made with MapPoint
Prediction made with Balloon Track

Prediction History is available here

EOSS Flight Day Frequencies:

Global Frequencies

EOSS-126 Balloon Frequencies

  • Cross Band Repeater
    • input 445.975 MHz
    • output 147.555 MHz
  • Beacons
  • APRS
    • 144.340 MHz
      • ID: AE�SS-11
      • DIGI: EOSS
      • Node: BALNOD
      • APRS Time Slotted Every 30 seconds at 0:00 and 0:30
      • Telemetry once a minute
        • power up at 58 seconds past the GPS minute to properly slot telemetry
      • Sample Data
  • 147.555 MHz
  • 426.250 MHz
  • ID: AE0SS
  • AM signal
  • GPS position overlay

Radio Coverage:

Green, you should be able to work the payload systems.

Red, is the border of the received signal. Red appears jittery because it is depicted topographically. Thus, the red dots on the eastern half of the map but well within the maximum distance show hilly terrain behind (east) which reception is not possible.

This is a generic 95,000 ft ASL coverage map for flights that depart from the vicinity of our launch site. Flight day coverage may vary depending on upper air winds.

Flight Systems:


Balloon Manufacturer Kaysam
Balloon Type latex
Balloon Size 3000 gram
Payload 21.4 lbs.
Free Lift % calculated at fill
Ascent Rate 1400 fpm estimated
Descent Rate 950 fpm estimated
Parachute 10 ft
Peak Altitude determined after flight
Launch Conditions determined at launch


Payload Configuration:

Tracking and Recovery Info:


Location X Y
Rt 71 & 14 (West Intersection) 70 60
Touchdown (see Prediction Page)


Tactical Callsigns

Tactical Callsign Name Notes
Alpha WA0GEH Marty and Dan Tracking and Recovery Coordinator
Bravo K0SCC Steve, Daryl and Parker  
Charlie KB0YRZ Chris  
Delta KC0UUO Rob  
Echo KC0RPS, N0SSW, W0NFW, KC0EOV Jim, Harlan, George Roger  
Foxtrot WB0DKT,KG6HXM, KC0ZIE,  WB6KDF Glen, Sam, Darren and Loren  
Golf KC0VJE Louis  
Hotel W0CBH, KC0SOW Benjie and Marcia and Sabrina  
India N0NDM Larry  
Juliet AE0SS Nick Ground Station
Kilo N0KKZ Rick prediction and data center
  KC0WJJ Brian CU Liason


Internet Gateway Stations:

as seen on Findu.Com

For AE0SS-11

  • AE0SS - EOSS Ground Station, Windsor, CO (KB0TVJ the operator, I think)
  • K0UT - Bill Beach, Ft. Collins, CO
  • KB0TVJ-3 - Russ Chadwick, Boulder, CO
  • KC0D-3 - Mark Patton, Foxfield, CO (new callsign)
  • KC0VJE-2 - Louis Perley, Erie, CO


  • KB0TVJ-3 Russ Chadwick, Boulder, CO
  • KB0TVJ-4 Russ Chadwick, Boulder, CO
  • N0PSJ - Christopher Holmes, Arvada, CO

EOSS wishes to express our sincere appreciation to the stations above who iGated the balloon APRS telemetry onto the internet. Did you know I publish predictions for i-gates? I keep a list of everyone who has ever i-gated an EOSS balloon flight. You're all in the list so if you're wondering when the balloon will pop up over your horizon, check out this page for future flights.  Currently predictions are being made for 28 i-gates.

We are relying heavily on real time position information available on the net to allow the FAA controllers to have up to the minute location data to assist them in air traffic control.

Redundant stations for the balloon iGating provide excellent coverage. If you are able to iGate we invite you to join the Internet Gateway Team. Contact me ( to be put in touch with the coordinator. By joining the team, you are giving peace of mind to the iGate coordinator for that flight. He knows you'll be there and he can rely on you.

Naturally, anyone can iGate data onto the net and even if you aren't a member of the team we will welcome your contribution to the internet based tracking effort. If you callsign appears on the log, you'll be shown as a contributing station as those above are.

Having more than one station covering each APRS beacon means that should a station drop out momentarily, the others can often maintain the data flow.

Thanks again guys! The FAA (and EOSS) are very grateful for your assistance in this endeavor.

Future I-Gaters:

Check out the EOSS I-Gate page for information on how to participate and why we need you.

Current I-Gate Stations:

Guys, the prediction program used to determine the track of the balloon prior to flight can now output a prediction for the Rise, Closest Approach or maximum elevation, and Set of the balloon for each of your stations. I have posted a prediction page for stations that I have been able to discover geographic coordinates. See the I-Gate prediction page for an example. The page will not be updated daily, however, it will be updated the evening prior to flight for I-gate planning purposes.

I have often been asked by iGaters when they should expect to either start receiving signals (AOS) or expect to see those signals disappear (LOS). This prediction page should answer all those questions for you.

Experimental Systems

Colorado University flew 3 balloon sats

EOSS Systems Tests and Experiments

New LI chemistry batteries will be tested on RMRL xband repeater.

note: customers are welcome to submit detailed synopses of their flights or web links to their own web sites.


Launch Site

  • page 1 - Launch Site activities
  • page 2 - Colorado University Student Teams

Recovery Area

Lunch After Flight


Rocky Mountain Radio League (RMRL) Cross Band Repeater

RMRL Mountain Top Repeater T&R Operations

Audio notes:

RMRL Xband:

The recorder wasn't started until the balloon had already ascended to an altitude of around 28,000 feet.

The ascent phase of the RMRL Cross Band repeater is heavily edited to remove repetitive CW ID traffic with no other meaningful communications. I attempted to retain 100% of the voice traffic but might have inadvertently edited out some traffic if it was way down in the noise.

The descent is NOT edited. However, my HT had the squelch set a bit tight so there are numerous short audio gaps due to polarization (spin) fading. But generally speaking this part of the audio should offer a 1:1 representation of the descent RF signal without VOX kicking in and shortening the length of the recording. This may prove interesting and valuable to folks who are trying to figure out when the xband repeater separated from the main payload train.

Recovery Repeater Audio Traffic:

I did fiddle slightly with the recovery frequency audio recordings.

In reality, Nick Hanks, N0LP, gives nice summation of what systems are on the flight string, then the first balloon is launched and escapes without the payload train.

I edited out the launch sequence for balloon number one and placed it in the first file above (1_eoss-126_repeater_release_snap.mp3). It's only a minute or so long.

Then I MOVED Nick's spiel to just in front of the launch of the second balloon. I mention it as you should know and also because Nick himself refers to the fact that a second balloon launch is about to happen. So if you are confused, that's what I did.

Other than this movement of Nick's overview, the rest of the audio is sequentially accurate. This recorder DOES USE VOX and pauses recording when any silent period lasts for more than 3 seconds. The timeline while sequentially correct does not accurately represent the elapsed time.


Short video of the first attempt at launch by Robert Slate, N0TQN


10 minute video from the onboard ATV system as recorded at the ground station. The Burst occurs approximately 7 minutes into this video.




Spread Sheets

Mapping Files