Recap of EOSS-49

All reports and additions to this recap are welcome. This is a preliminary attempt.

LAUNCH DATE: April 21, 2001
LAUNCH TIME: 15:00 UTC - 09:00 MDT
LAUNCH SITE: Windsor, Colorado, Gene Fatton�s Ranch

  • 40.4744 Degrees N. Latitude
  • 104.9628 Degrees W. Longitude

PRIMARY INTEGRATOR: Colorado University


Here are the Colorado University Student proposals in PDF files. I have edited the files to remove personal contact information of anyone other than Chris Koehler. If you wish to contact a student, go through Chris.


Preflight Foxhunter Net:  

  • 147.225 MHz Colorado Repeater Association, 8:00PM the preceding night

Launch Site: 

  • Simplex 146.550 MHz

HF Net:

  • 7.235 MHz +- QRM, Bruce NA0BR

Tracking Team:

  • 449.450 MHz Rocky Mountain Radio League (RMRL) (pending approval)
  • 146.58 MHz Simplex Field Frequency

Payload Frequencies:


  • 144.340 MHz FM (350 milliwatts output).  
    • CW beacon and cut down system

APRS Output

  • 144.340 MHz - This APRS/GPS beacon will be transmitted by the W5VSI payload. See that page for data format information.


  • 426.250 MHz.

N�LP Charts

Nick Hanks has made some charts of the data from EOSS-49


Hi everyone;

The EOSS had two flights this past Saturday, the 21st of April, 2001. We did work both flights with Kevin Shoemaker, Pete Goldman, Robert Slate & another fellow who's name I don't have present. Also Eric Richards made a cameo appearance.

From a DSES viewpoint, the exercise generally went real good with good to excellent ATV reception until the ATV battery died somewhere near the state line not to long after burst. (An EOSS inspection revealed a battery failed when it should not have.)

From a EOSS viewpoint, the results were mixed. The first flight, EOSS-49 accomplished it's mission and was recovered. The second flight, EOSS-50 made altitude, lost telemetry at burst at 104,000 ft and we lost the beacon about 20 minutes from touchdown and it has not been recovered. The tracking and recovery teams seem to have never heard the beacon.

Two errors prevented this from being a perfect flight. The first was that although the video is at 426.250 MHz the radio needs to be tuned to 430.750 MHz +/- 1 MHz. I understand that this is due to the way the ICOM tunes the video. We actually need to tune to the audio carrier frequency which is about 4 MHz higher than the video. We knew this before launch but did not do so until after launch so we missed the launch.

The second error was an (about) 10 degree bearing error from the GPS prediction to actual. The balloon location is received via telemetry and Slate moves the cursor on his Garmin 3 GPS to that location. The Garmin then shows a bearing. It worked very well on EOSS-47 but not on this flight. The Garmin is set for true, not magnetic and the dish selsyns are correct. The Garmin bearing would be say 53 degrees when the target was found at +/- 42 degrees. No cause has been determined yet.

I suppose a third error could be mentioned where Slate started tearing down the gear before the second flight ended. Sorry Kevin...

The main VCR worked, but not as well as the cam-corder. If not for the cam-corder, the video tape quality would have lowered the success level. I believe a head cleaning is in order. Incidentally, video failures on the last two flights, #47 & 48, seem to have been EOSS problems, not DSES failures. We do need to get audio on the VCR tape, preferably packet & tracking/recovery.

From a hardware viewpoint, we did pretty good. Wind was again an issue but both a lower gear ratio and working and controllable brakes should take care of that.

We also installed an old RG-8U cable thru the wavequide on the upper pylon from the feed to the base of the tower. This is to provide both DC power to the feed and to provide a ground for the feed point hardware. The waveguide also needs to be grounded at both ends. Unless someone has a better idea, we're going to terminate the RG-8U at the box at the feed box with an RG-259 bulkhead connector. We did not use this cable on this flight.

At least one of the VF drives does generate some hash on the video, probably the one sitting next to the VCR. A PLC in the shack did not but it wasn't wired to anything. Since both VF drives will be installed in a shielded box inside the tower this situation should be resolved.

Pete verified that his controller still operates the elevation drive via the PC and is going to wire the new azimuth drive to it also. At that time PARATRAK will be back in service.

After the ATV signal tracking was complete and the RG-8U was installed we used the dish to track the 2 meter beacon of EOSS-50 with the 70cm hardware. We were successful and the feedpoint pre-amp did help, but I hope that 2 meter hardware would perform better.

Robert Slate, N0TQN