Flight Recap for EOSS-173

04/14/2012 10:49 (CDT): Finished, but additional data is always welcome

Flight Coordinator: Doug Gentges
LAUNCH DATE: February 25th, 2012 (wx delay +1 day)
LAUNCH TIMES: 07:16:30 am MST (14:16:30 UTC)
LAUNCH SITE: Windsor, CO (Click Here for directions)

Pre-flight Prediction and Actual Tracks

E0SS-173 AE0SS-11

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 (NO DESCENT TRACK)
Prediction and Actual tracks made with Balloon Track

Maps by Google Earth

E0SS-173 K0SCC-11

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 (NO DESCENT TRACK)
Prediction and Actual tracks made with Balloon Track

Maps by Google Earth

Above Map Files available in the Data Section below

Launch Site - Windsor
Launch Point: 40.47367� lat.   -104.96233� long.
Grid: X=-37.46 Y=40.57
Ascent Rate: 1329 feet per minute
Descent Rate: 950 feet per minute
Altitude: 4931 feet
Predicted Landing Site
Landing Point: 40.37095� lat.  -103.51445� long.
Grid: X=38.7 Y=33.5
Altitude: 4500 feet
Flight Time: 114 Minutes
Bearing: 94.9� True
Range: 76.4 Mi.
Actual Landing Site
Landing Point: 40.40594� lat.  -103.5092� long.
Grid: X=38.9 Y=35.9
Bearing: 93.0� True
Range: 76.504 Mi.
Difference from Predicted to Actual Landing Site
Bearing: 6.6� True
Range: 2.429 Mi.

Final Pre-Flight Prediction is available here
Prediction History is available here

EOSS Flight Day Frequencies:

Tracking and Recovery Frequencies

  • Preflight Net:
    • 147.225 MHz 8 pm MDT preceding night
    • 146.640 MHz will serve as a backup frequency
  • Tracking and Recovery Operations
    • Repeaters 
    • Field Simplex Frequencies  
      • 446.100 MHz simplex for field recovery operations
        • Note: Some radios insist on incorrectly placing a negative 5 MHz offset when selecting frequencies from the simplex portion of the 70 CM band. Check your radio and if this is the case. Consider programming in this simplex frequency to a memory channel as some radios have demonstrated the annoying habit of re-inserting the offset if you momentarily shift to a repeater then return to the simplex freq. Check the operation of your radio on this simplex freq to be ready for however your radio behaves.
      • 146.550 MHz Backup field simplex
    • Repeater Coverage Pages - Listings of all repeaters available in the expected flight areas.
    • There may be FRS operations see THIS PAGE for a list of channel numbers and their associated UHF Frequencies.
    • HF (possible but not pre-arranged as of this update)
      • 3.810 MHz LSB
      • 7.235 MHz LSB
  • Launch Site Simplex
    • 146.550 MHz


EOSS-173 Balloon Payload Frequencies

  • Beacons
    • 147.555 MHz
      • CW ID: K0SCC-11
    • 28.320 MHz
    • CW ID:
    • Altitude in 14 WPM CW
  • 144.340 MHz
    • ID: AE�SS-11
    • DIGI: EOSS
    • Node: BALNOD
    • APRS Time Slotted Every 30 seconds at 0:00 and 0:30
      • power up at 58 seconds past the GPS minute to properly slot telemetry
    • Telemetry once a minute
    • Sample Data
  • 147.555 MHz
    • ID: K0SCC-11
  • 145.600 MHz
    • ID: K0ANI-11
  • Telemetry
    • 28.223 MHz
      • 0.1 Watt output
      • ID: N0HF
        • ID and Altitude on CW



Video Might Be available, check http://www.eoss.tv

Various Online Live Tracking Pages

Flight Systems:


Balloon Manufacturer Totex
Balloon Type latex
Balloon Size 1200 g
Neck Load 12.7 lbs.
Neck Lift 16.5 lbs.
Ascent Rate 1329 fpm estimated
Descent Rate 950 fpm estimated
Parachute 8.5 ft.
Peak Altitude 85,000 ft. estimated
Launch Conditions determined at launch

Payload Configuration:

Payload Experiment Designer

This is an EOSS test flight to qualify payloads. Some payload systems from outside entities may/will be flown.

Experimenters are welcome to submit websites for linking or overviews which I will post on a page on the EOSS website.

Internet Gateway Stations:

as seen on Findu.Com (listed alphabetically)

EOSS-173, AE0SS-11

  • KB0TVJ - Russ Chadwick, Boulder, CO
  • KC0VJE - Louis Perley, Nunn, CO
  • N0EB-1 -  Richard Beggs, Thornton, CO
  • N0IX-12 - Doug Gentges, Tracking and Recovery Mobile iGate
  • N0PSJ - Christopher Holmes, Arvada, CO
  • N0SPB - Shaun Bryant, Commerce City

EOSS-173, K0SCC-11

  • K0ANI - Larry Cerney, Denver, CO
  • KB0TVJ - Russ Chadwick, Boulder, CO
  • KC0D-3 - Mark Patton, Foxfield, CO
  • N0SPB-10 - Shaun Bryant, Commerce City

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 30 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 (webmaster@eoss.org) 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 findu.com 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.

Tracking and Recovery


  • McDonalds in Ft. Morgan (Google Map)
  • Meet at 6:00
  • Leave by 6:30  for recovery ops



  • Fill up with gas!
  • Wear warm clothes and good boots.
  • Bring tow ropes!
  • DF bearings will be early in the flight.




Grid X

Grid Y

West Intersection of CR 71 and CR 14 30 50
Test Coordinates   40.75� N  x  -103.5� W 39.2 59.6



Tactical Call Signs 





Alpha WA0GEH & KC0D Marty & Mark Tracking and Recovery Coordinator
Bravo K0SCC Steve, Parker Tracker, Optical Tracking Asset, Food and Beverage
Charlie KC0ZIE, WB0DKT Darren, Glenn Trackers
Delta KB0YRZ Chris, Victor Tracker
Echo W9CN Mike Tracker
Foxtrot KC0RPS, N0SSW  Jim, Harlan Tracker
Golf N0IX Doug Flight Coordinator & Tracker
Hotel N0NDM Larry Launch Coordinator, Tracker Pro Tem
India KC0UUO, KD0QYY Rob and KJ imperator pro permaneo, et uxor

Text Recaps


Launch Site


SamCam2 Pictures

note: The Canon 570IS's automatic lens cover did not fully retract that is what is causing the slightly inclined black bars above and below the landscape oriented photos. Still, plenty of nice scenery is visible even with this problem.

Ascent Descent
Looking Up Looking Up
Looking to Horizon Looking to Horizon
Looking Down Looking Down

Recovery Site






Pre-Flight Preparations and Launch of EOSS-173

by Nick Hanks, N0LP



EOSS-173 Flight Vdeo

GoPro Hero



EOSS173 Ascent Timelapse





EOSS-173, AE0SS-11


 Spread Sheets

Mapping Files


EOSS-173, K0SCC-11


 Spread Sheets

Mapping Files