THE NORTH TEXAS HAM RADIO BALLOON PROJECT 16

AUGUST 9, 2008    HILLSBORO TEXAS

The North Texas Balloon Project was launched on Saturday, August 9, 2008 from the Hillsboro Airport South of Dallas, Texas

The planned high altitude balloon carried Amateur Radio Transmitters aboard including a cross band 2/440 repeater and voice beacon along with GPS locating equipment.
(Details of the radio equipment aboard can be found at this link (  http://www.ntexbp.org/ )

This page contains audio files from the voice beacon and the 2 meter side of the onboard repeater transmitters.

The recording QTH was located in Gun Barrel City, Texas, about 60 miles from the launch site at the Hillsboro Airport.

Equipment , Software and web sites used:
Compaq Computer using Wave Pad audio recording software
Receiver was a Radio Shack HTX- 212 (Used "A" and "B" vfo with preset frequencies)
Receiving antenna - 2 meter homebrew Slim Jim up about 10 - 12 feet from the ground fed with RG-58 coax. Total length of coax, about 20 feet.
Yaesu FT-107 monitoring HF 40 meter ground frequency with Hustler 4BTV antenna.
Websites used:
http://www.dfwaprs.net/ (For GPS locating, altitude, etc)

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I started listening to the voice beacon and the repeater downlink at exactly 8:30AM Central until I first started hearing ANY signal from either of the balloon transmitter frequencies by switching between the A and B vfo's on the receiver. At 21 minutes from the presumed launch time, I started hearing very weak signals and started a continuous recording of the flight at about the 22 minute mark.

I did not hear a countdown to launch on 40 meters due to extreme QRM so it is presumed that the launch took place at the scheduled launch time of 8:30AM Central time.

At 21 minutes past the 8:30AM time (8:51AM local), I started to hear some very weak signals and started recording shortly thereafter, and over the next 2 hours and 19 minutes, I recorded the entire length of the flight from launch until presumed landing.

The below recordings are only a small portion of the audio recorded starting with the earliest at 21 to 22 minutes into the flight: Some are large files so be patient.

ntbp22min.mp3 (First audio heard from repeater) 76kb

ntbp26min.mp3 (Repeater audio) 78kb

ntbp29mins9audio.mp3 (Repeater audio) 567kb

ntbp37minbeaconid.mp3 (Beacon ID in CW) 37kb

ntbp37minbcnrpts30711ft.mp3 (Voice beacon status report from 30,000 feet) 369kb

ntbp1422utcs9bcnreportc.mp3  (Voice beacon status report at 1422 UTC) 422kb

Selected QSO's:
ntbpqso1.mp3 218kb
ntbpqso2.mp3 104kb
ntbpqso3.mp3 139kb

Final Voice Beacon Transmission????
It is believed that this was the last transmission heard by anyone due to a malfunction of the beacon transmitter. This appears to have happened on the way down at around 49,000 feet (assuming data was accurate), with an "inside" temperature of -46 degrees! (Minus 46 degrees)
There were no further transmissions from the beacon transmitter heard by my station. Listen closely to the recording, it ends abruptly and goes to noise when it attempts to start another report!
ntbplastbcnrpt1542utc.mp3 516kb (Final Voice beacon heard! Status report at 1542UTC)

Final observations and notes:
The 2/440 repeater continued to function normally thru the remainder of the flight and the last transmission heard at this station, although very weak, was at about 13,000 feet according to GPS tracking. It was in the noise level and no more transmissions were heard below this altitude.

As you listened to the recordings, you can tell that many were "full quieting" (no background noise).
Some recordings made were Full Scale on the S meter on the radio.

On the average, most signals heard from the balloon had some heavy oscillation in the S meter readings due to movement, etc of the balloon.
According to GPS readouts, the maximum altitude appeared to reach about 83,000 feet as reported on the http://www.dfwaprs.net/ web page.

Below is a map of the landing area taken from the above web page.
On the map, W5SJZ-11 is the balloon. You can see various "chase" vehicles also.
The landing area is about 10 miles East of Meridian, Texas near highway 22, West of Lake Whitney, Texas. Total distance from my station was about 84 miles with a flight distance of about 25 miles from the Hillsboro airport according to my unvarified measurements.

(Exact location of landing site may be slightly different)

As a further note of interest for whatever it is worth, when I was monitoring the S meter readings on the receiver during all of the flight, I noticed that at the "maximum" altitude, the S meter readings were weaker than during lower altitudes. I believe this may have been caused by the pattern of the Slim Jim antenna being very near to the ground.

"Facts and numbers" in this article are believed to be accurate,
but, check with the http://www.ntexbp.org/ for details. 
 I hope you have enjoyed looking and listening to the "sounds from near space" and I would like to congratulate the very dedicated hams and all concerned at the North Texas Balloon Project 16 for a job well done.
It certainly was a fun experience for me! 

73,  N4UJW