Joe Leggio WB2HOL
This FOX-BOX is based on a single CMOS 555 timer and uses an ISD1000 chip to store the transmit ID.
The two main controls are used to set the interval between transmissions and the duration of the transmissions.
A DPDT relay is used to supply two external sets of switching contacts.
One set is used to key the Push-To-Talk line of the transmitter, The second set of contacts can be used for devious circuits. I once used them to cycle power to an antenna rotator holding a three element Yagi. The beam rotated about 270 degrees during every transmission. I had the interval set to transmit once every minute and the duration set for about 15 seconds. This kept the transmitter on long enough to give my ID and anounce I was the fox. Hunters found it *very* difficult to get a bearing using hand held beam antennas. I'm not sure if one team ever started talking to each other again since that hunt. :-)
The front panel is a piece of PC board cut to size and spray painted with white enamel. It was labeled using rub-on transfer lettering.
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Copyright 1997 - Joseph Leggio - all rights reserved.