The Lunch Bunch T-Hunt Results
The very first Lunch Bunch T Hunt took place during the week of Feb 27, 1995.
This was a new sytle of hunt for some of the active Orange County, CA
T hunters. The transmitter was programmed to transmit for 2 minutes,
from 12:05 until 12:07 pm each day. There were 3 to 5 hunters
taking bearings each day, before getting together for lunch (with the
tight-lipped hunter) to collaborate information and to choose the next
day's starting locations. The boundries were about a 30 square mile
area centered around John Wanye Airport. The goal was to find the
transmitter by Friday's lunch, and the T was found one day ahead of
schedule, not bad for such a LOW duty-cycle hunt.
The transmitter consisted of a Kenwood TH78A, a RaCon 6805 radio
controller, and a 12V 10ah gel-cell battery. It was all enclosed
in a ammunition can, modified to be locked shut and chained up.
The fox box also had a BNC feedthru connector and a home-made 1/4
wave spike made from very thin steel piano wire. The RaCon was
programmed to run at a 66% duty cycle, running a voice ID, some tones,
and a morse code ID. The on time lasted 10 seconds, followed by a 5
second off time. The Kenwood was programmed to turn itself on using
the built-in clock at 12:05 and then turn itself off two minutes
later. If the radio is powered on wile the PTT is active (the radio
and the RaCon were not syncronized), the radio would wait until the PTT
was released and re-applied before transmitting. Therefore, on average,
the T was only on the air about 70 seconds per day. The box was chained
to a fence among large swampy brush. and buried under grass and twigs.
Here are the bearings, plotted each day by color. After Monday
(red), with three bearings, all crossing just north of the 405
Freeway at Von Karman, the hunters decided to surround the
intersection of Main and Von Karman. On Tuesday (green), the
bearings were not as much in agreement, but they did move the
hunters to center Jamboree and the 405, about 1/2 mile away in
roughly the proper direction. On Wednesday (blue) bearings
were scattered again, but one hunter was very confident in his
bearing, and since he had a full scale reading with 40db of
attenuation, all hunters decided to cover Carlson. On Thursday
(not plotted), all bearings pointed at the T. One hunter was Doppler
equiped, and was able to find the T, which was about 20 feet from the
road, just as that day's transmissions ended.
Well, we learned a few things:
- There were many tall buildings to the north and west of the T, and
because most all bearings were from the north and west, there were
very few "good" bearings.
- A doppler was very useful near the end of the hunt.
- Cooperative T hunting is a little different from competitive T hunting,
try it peoiodically.
- Consider which bearings to trust, and which ones seemed "bad".
Concentrate future hunts around the "good" ones.
- Syncronize someone's watch to the T. It's nice to know when it is about
to turn on.
All in all, it was a lot of fun. Thanks to N6ZAV, KO6KC, KD6IFZ, KN6UX, and
KM6BT for participating. We would love to hear more about low duty cycle or
any other T hunts.
73 de KD6BCH
This page by Byon Garrabrant
N6BG email@example.com 12/24/97