Announcement of EOSS-136/137

EOSS-136/137 Flight Coordinator: Jim Langsted, KC0RPS

LAUNCH DATE: April 11th, 2009 (wx +8, SUNDAY, April 19th)

  • EOSS-136: 06:50 MDT (12:50 UTC)
  • EOSS-137: 07:10 MDT (13:10 UTC)

LAUNCH SITE: Windsor, CO (see directions)

Payload Experiment Designer

  • Colorado University Rocket Sat AirCore
  • NOAA Dropsonde
  • Colorado University Demo Sats

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

EOSS Flight Day Frequencies:

Tracking and Recovery Frequencies

  • Preflight Net:
    • 147.225 MHz 8 pm MDT the evening prior to flight day
      • 145.160 MHz simulcast in the Springs
      • 145.460 MHz simulcast in Boulder
    • 146.640 MHz will serve as a backup frequency
  • Tracking and Recovery Operations
    • Primary Frequencies
      • 449.450 MHz RMRL (103.5 Hz tone) Windsor Launch site
      • 447.275 MHz NCARC (100 Hz tone) North of Fort Collins into Wyoming
    • Backup/End Game Frequencies
      • 449.300 MHz (131.8 Hz tone) Lat/long:  41.14/-104.76, eastern Cheyenne, great coverage south of I-80 and into the recovery area, may use this in lieu of 146.55 as it would provide good coverage in hilly terrain.
      • 147.105 MHz (114.8 Hz tone) Eastern Cheyenne, linked to Albin repeater on 147.165+, runs weather net in morning
      • 147.165 MHz (114.8 Hz tone) WY/NE border, north of I-80, linked to Cheyenne 147.105, runs weather net in morning
      • 146.550 MHz simplex (same simplex for field and launch ops)
      • 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.


EOSS-136 Balloon Payload Frequencies

EOSS Operational Frequencies

  • Beacons
    • 147.555 MHz
      • CW ID: AE0SS
  • APRS
    • 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

NOAA Frequencies

  • Dropsonde Telemetry
    • 438.250 MHz Wideband FM (~250 KHz wide at 100 mW)


EOSS-137 Balloon Payload Frequencies  

  • Beacons
    • 145.600 MHz
      • CW ID: K0SCC
  • APRS
    • 144.340 MHz
      • ID: KC0YA-11
      • DIGI: EOSS
      • Node: BALND2
      • APRS Time Slotted Every 30 seconds at 0:15 and 0:45
        • power up at 13 seconds past the GPS minute to properly slot telemetry
      • Telemetry once a minute
      • Sample Data
  • 145.600 MHz
  • ID: K0SCC-11

Flight Systems: 


Balloon Manufacturer Kaysam
Balloon Type latex
Balloon Size 3000 gram
Neck Load 26.3 lbs.
Neck Lift 31.6 lbs
Ascent Rate 1400 fpm estimated
Descent Rate 1000 fpm estimated
Parachute 8.5 ft.
Peak Altitude determined after flight
Launch Conditions determined at launch



Balloon Manufacturer Kaysam
Balloon Type latex
Balloon Size 3000 gram
Neck Load 23.7 lbs.
Neck Lift 28.2 lbs
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:

submitted by Marty Griffin, WA0GEH (Alpha) and Nick Hanks, N0LP

Hello Trackers,

The upcoming EOSS-136/137 adventure is pretty complex. Nick and I have been chatting about the logistics of getting everyone into the field where they need to be at the right time. This will take unique tracker participation from Mike W9CN, Chris KB0YRZ and Larry K0ANI. Here�s the current scoop.

First, as most of you now know the balloons are going north and most likely out of range of the trusty 449.450 MHz repeater. Our current planning is to use a 70 cm repeater operated by the Northern Colorado Amateur Radio Club. The repeater is located northwest of Fort Collins at 7727 ft.. We know it has coverage in Cheyenne and some folks will be testing it for us on I-80 towards the WY-NE state line. It�s on 447.275 MHz, negative shift, and 100 Hz PL tone.

EOSS 136: This flight will be the first one on Saturday. Currently launch time is 06:50 AM. It has three payloads sponsored by NOAA. A prototype, 38 gram (0.1 lb.) dropsonde designed to be dropped from a UAV into a hurricane, a prototype meteorological package meant to support future NOAA missions, and a variation on the AirCore sampler we flown before only this one is destined to fly on a rocket from Wallops Island this summer. Since the dropsonde is not designed for very high altitude operation, we�re going to cut the payload string loose at 70,000 ft. Post-flight turnoff instructions on the met package and the AirCore will be provided on the net Friday night. The dropsonde will be turned off by the design team, ARA. The ARA folks will be collecting data from the dropsonde using two cars. We need to support their data collection.

EOSS-136 ARA Dropsonde

The ARA dropsonde teams will deployed as tactical �ARA Car 1� and �ARA Car 2�. Both cars will be using mag mount antennas to receive the dropsonde signal on 438 MHz.

For ARA Car 1, the intent is to pre-deploy into the field at about the projected burst point and about 10 miles north to northwest to avoid being directly under the dropsonde. The ARA Car 1 team�s objective is to acquire and capture as much data as possible without blanking out the received signal with our 70 cm net transmissions. ARA Car 1 will have Brian Zadler (ARA, ph number redacted) and Tim Samaras WJ0G on-board. The plan is for ARA Car 1 to meet us at the breakfast site and then trail Chris KB0YRZ to the point described above. Chris and the ARA guys will determine where to position themselves after reviewing N0KKZ�s prediction from either Friday night and/or Saturday morning. Chris will communicate with ARA Car 1 via WJ0G on 146.55 MHz and with our net on 447.275. He will lead about � mile ahead of ARA Car 1. The ARA Car 1 team will set up a 70 cm beam to receive signals from the dropsonde, probably from a high point just off I-80. Chris will assist with this by providing periodic updates of the balloon�s elevation angle and bearing. Shortly after cut away or just before, Chris will lead the ARA Car 1 team to the predicted recovery area where they will attempt to continue to receive the dropsonde signal during final descent. If ARA Car 2 is receiving data well, ARA Car 1 could depart for the landing area before cutaway. That�s an ARA call. The decent data is very important for this experiment is it will allow evaluation of the impact of component warming.

ARA Car 2 will bring the dropsonde to the launch site, assist with getting the dropsonde on the flight string and checked-out, monitor the launch, and then verify the signal from the dropsonde. After the launch and verification, Mike W9CN will lead the ARA Car 2 towards the balloon (via I-25 and I-80 hopefully), but will lag behind and to the north of the balloon trajectory to avoid 70 cm interference from net transmissions. On board the ARA Car 2 is Doug Meegan, the ARA lead (ARA, ph number removed), and a driver or two. Mike and the ARA Car 2 will communicate via FRS radio. He�ll be on the 447.275 net also. Mike will also need the latest predict file and know how to quickly get to the predicted landing site. At burst, Mike will lead the ARA Car2 to the recovery site while trying to maintain dropsonde reception in ARA Car 2. Tough assignment, but Mike�s �driver� can get it done.

During the operations, the ARA Car 2 may choose to �leap frog� over ARA Car 1. This choice is up to the ARA folks during operations time.

EOSS 136: NOAA/CU AirCore Team

On EOSS 136 will be the NOAA/CU AirCore experiment to collect an atmospheric sample and to test the closure of the AirCore intake valve at 30K feet. The team (tactical AirCore Team) of 4-5 CU students will be advised by the ground station as to where to go to meet a tracker team in the field. Alpha (Marty and Mark) will provide this data via the 447.275 net. Most likely the students will go up I-25 and then to the East on I-80. Alpha will advise who to meet and any meeting location change via the 447.275 net and maintain telephone contact with the AirCore Team. This team needs to arrive at the landing site as soon after landing as possible to check the AirCore valve and to turn-off the met payload.

EOSS 137: University of Colorado DemoSats

EOSS 137 will launch about 15 minutes after EOSS 136. This flight will carry a string of CU DemoSats similar to what we�ve flown in the past. The students for the DemoSats will launch and then travel to the recovery site. Larry K0ANI will first assist with payload string preparation and launch, and then he will lead the CU students to the recovery site which will be about 10 miles further out than EOSS 136 since this balloon will be allowed to burst. Larry will communicate with Alpha on the 70 cm net. Steve K0SCC will bring his new APRS module to the launch site, assist with launch, and then will be leaving after -137 is away. He will be conducting some commanding experiments with his payload K0SCC-11 on 145.600 MHz. Once in the landing area ,he will assist in the recovery of EOSS 137.

As Ross Perot would say, �It�s just that simple.�


  • Johnson's Corner (Exit 254)
  • 5:00 AM



Grid X

Grid Y

Launch Site, Windsor
lat = 40�
28.420' long = -104� 57.740' 



TrackPoint Test 40� 45' N,  104� 30' W        34.1 29.0


Tactical Call Signs







Marty & Mark

Tracking and Recovery Coordinator




W/ ARA Car 1   




W/ ARA Car 2



Glenn, Sam

Glenn, Loren, Andrea, David, Sam, Suzanna - Family Affair!




Remaining at the launch site



Steve & Daryl

Launch and Chase



Doug, Harlan

Hotel KC0UUO Rob Presidential Limo   
India KB0LP Dave  




Launch Coordinator�tentative tracking




Ground Station