Announcement of EOSS-120

LAUNCH DATE: July 21th, 2007
LAUNCH TIME: 07:15 am MDT (13:15 UTC)
LAUNCH SITE: Crow Valley Park, Briggsdale, CO (directions)

Pre-Flight Information

On Air Nets

Check into the weekly EOSS net every Tuesday evening, except the 2nd Tuesday of the month when we hold our face to face meetings.

  • Tuesdays at 8 PM (20:00) Local time
    • 147.225 MHz 107.2 Hz tone CRA Repeater (Denver)
    • 145.460 MHz 107.2 Hz tone CRA Repeater (Boulder) manual link required (link may be unavailable)
    • 145.160 MHz 107.2 Hz tone CRA Repeater (Colorado Springs) full time link active
    • 146.640 MHz backup DRL Repeater (Denver only)

Pre-Flight Coordination Net

The evening prior to flight we hold a coordination net at 20:00 Local Time to assign the grid information and tactical callsigns. Any last minute information, launch time changes, launch location changes, maybe even a cancellation will be announced on this net.

  • Preflight Net:
    • 147.225 MHz 8 pm MDT preceding Saturday night
      • 145.160 MHz simulcast in the Springs
    • 146.640 MHz will serve as a backup frequency

Tracking and Recovery Team
Flight Day Breakfast

  • Johnson's Corner
    • I-25 Exit 254
    • arrival time 4:45
    • departure time 5:30

EOSS Flight Day Frequencies:

Global Frequencies

EOSS-120 Balloon Frequencies

  • Beacon
  • 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

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 25.6 lbs.
Free Lift % calculated at fill
Ascent Rate 1100 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
West Intersection of Highways 71 and 14 60 35
Touchdown (see Prediction Page)


Tactical Callsigns

Tactical Callsign Name Notes
Alpha WA0GEH and N0AUS Marty and Al Tracking and Recovery Coordinator
Bravo KB0YRZ and KC5TRB Chris and Harry  
Charlie WG0E and N0MPM Colin and Mike  
Delta W0CBM and KC0SOW Benjie and Cia  
Echo KC0RPS Jim  
Foxtrot WB0DKT, KC0ZIE, KC6HXM, WB6KDF Glenn,  Darren, Sam and Loren  
Ground AE0SS Nick Ground Station


Internet Gateway Stations:

Future I-Gaters:

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

Current I-Gate Station:

If you are present at your iGate during the flight try and monitor the tracking and recovery frequency. The ground station likes to check the frequency prior to launch to find out if any stations are out there ready to igate the traffic onto the net for the FAA to monitor.

The prediction program used to determine the track of the balloon prior to flight can now output a prediction for the Rise, Closest Approach, 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.

Your Log Files

Our technical committee members would also request you open a log file and record all the packets you hear and forward onto APRS-IS. Whenever there is a technical failure of a package it is always helpful to have the most complete dataset possible to attempt to determine the cause of failure and possible fixes. After a flight send your data files to me (webmaster) and I will distribute them to the appropriate payload builders. They appreciate these logs even if all goes fine during a flight.


  • Colorado University - Upward Bound - Student hands on training

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