THE NORTH TEXAS
HAM RADIO BALLOON PROJECT 16
AUGUST 9, 2008 HILLSBORO
The North Texas Balloon Project was launched on Saturday,
August 9, 2008 from the Hillsboro Airport South of Dallas,
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.http://www.ntexbp.org/ )
of the radio equipment aboard can be found at this link (
This page contains audio files from the voice beacon
and the 2 meter side of the onboard
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
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.
http://www.dfwaprs.net/ (For GPS locating, altitude,
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
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
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
ntbp22min.mp3 (First audio
heard from repeater) 76kb
ntbp26min.mp3 (Repeater audio)
ntbp29mins9audio.mp3 (Repeater audio) 567kb
ID in CW) 37kb
(Voice beacon status report from 30,000 feet) 369kb
ntbp1422utcs9bcnreportc.mp3 (Voice beacon status report at 1422 UTC) 422kb
Final Voice Beacon
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
As you listened to the
recordings, you can tell that many were "full quieting" (no background
Some recordings made were Full Scale on the S meter on the
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
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.