EOSS-345 Colorado Space Grant Consortium Summer Launch - Recap

A single 3000g balloon was launched on July 29, 2023. Text book perfect is a comment I heard today!  The balloon was released at 102,479'

Beautiful sunrise at the Limon Ball Field, easy set up for the launch team.  Students excited, pay loads strung, beacons operating, ballloon on the field and away 345 went just after 7:00am.  We watched the balloon and payloads for a long time after the release. The flight itsself wasn't going far so we stayed at the Ball Field until after burst. The trackers and ground station started to narrow down the actual landing location.  When we were pretty sure of the cross roads the students headed out.  We held at County Road 2W and County Road 25, looked up and there the flight string and parachute were sailing above us.  The trackers then had us move over to County Road 26 as we caught up with the trackers they were talking to the landowner who just happened to drive down the road.  The fastest landowner access on record??  We drove down a private road and we could see the parachute about .35mile away.  We were warned of the open field cattle, cactus, snakes and the need for water and hats.  18 of us walked out to retrieve the payloads. The only incedent was the horses who were running up to us thinking we had food. Rob easily moved them away from us.  Back to Limon by 10:30.

Side note about the students and parents that were with us today.  This is a 10 week intensive course, hard to get into.  Parents from Seattle and St Louis flew in to watch their sons participate in this launch, others drove to Limon.  Parents helped with the launch, walked in to retrieve the payloads. Good day all around.


Thank you to the City of Limon for the use of the Ball Fields, a great place to launch our balloons.

Link for member mileage reimbursement

Original Announcement: 
  • 07-14-2023Update to the number of balloons anticipated 

One 3000g balloon anticipated, carrying payloads developed by Colorado Space Grant Consortium, Arapahoe Community College and Colorado State University.  To view  latest prediction, navigate to https://www.eoss.org/predict/  You can follow along and see the balloon positon live at https://track.eoss.org

Event Date: 
Saturday, July 29, 2023 - 07:00 to 23:45
Flight Coordinator: 
Launch Site: 


Colorado Space Grant Consortium will launch 3 payloads on a single heavy balloon.  Launch date July 29 wx July 30.  Launch site is Limon, Colorado.  We will launch from the south ball field.  DO NOT drive on the grass.

Balloon Type: 
Rocket Man 12 ft Release Adam
144.905KC0D-2Remote release-DF
ADSB N991SSICAO Code ADD7FBSquawk 4453 (Balloon)
Payload Plan: 

EOSS Preflight Net @ 7 PM Mountain Time the preceding night:
        •  449.225 MHz (-5 MHz Offset, 141.3 Hz CTCSS) Rocky Mountain Ham Radio (RMHAM) Repeater and EchoLink *CANONCTY* conference and the Fun Machine linked system
        • 146.940 MHz (-600 KHz Offset, 103.5 Hz CTCSS) Rocky Mountain Radio League (RMRL) Repeater if the RMHAM machine is down
        • 146.640 MHz (-600 KHz Offset, 100.0 Hz CTCSS) Denver Radio League (DRL) Repeater will serve as a backup to the backup repeater 

Flight Day:
Launch Site:
        • 446.050 MHz Simplex  
        (Note that some radios assume these are repeater frequencies and attempt to put a 5 MHz offset in the transmit frequency automatically)

Track & Recovery Operations:
        • 449.450 MHz (-5 MHz Offset, 103.5 Hz Tone) RMRL repeater

Hugo:  447.150 (-5 MHz Offset, 103.5 Hz Tone)

Limon: 447.650 (-5 MHz Offset, 103.5 Hz Tone)

        Simplex Frequencies:
        • 446.100 MHz Balloon #1 Field Simplex 
        • 446.150 MHz Balloon #2 Field Simplex
        • 446.200 MHz Balloon #3 Field Simplex
        • 446.275 MHz Car to Car drive out Simplex
        (Note that some radios assume these are repeater frequencies and attempt to put a 5 MHz offset in the transmit frequency automatically)

Digital Mobile Radio (DMR):

The decision as to which talkgroup use will be made by the EOSS RF Coordinator on a per flight basis.

  • Rocky Mountain Wide Network – Talk Group 700 - Rocky Mountain Ham Radio has approval to the use "Wide" for flight operations.
  • Central Colorado Regional Network – Talk Group 720 - On occasion, EOSS may use the Central Colorado Regional Network (Talk Group 720).

        Legacy 2M Simplex Frequency (not generally used due to desense/interference issues with the 2M APRS packets)
        • 146.550 MHz Simplex

2M Direction Finding Frequencies:

  • 144.340
  • 144.360
  • 144.905
  • 145.535
  • 145.645
  • 145.710
  • 145.765


Tactical Calls: 
TacticalCall SignNameNotes
AlphaWAØGEH, KCØDMarty, Mark
CharlieKCØRPS, WØNFWJim, George
FoxtrotNØRPF, K0BRARob, Doug
Ground StationN2XGL, K5JKJeff, Tom
GolfKØNKKNancyFlight Coord