Transponder 101

 

Theory of operation:

Antenna configurations for BOAT patterns (BAPM):





Antenna configurations for WALKING patterns (WAPM):

Measuring a transmit antenna pattern with transponder in continuous wave (CW) mode:

Transponder parts:

                            Download: APM Crib_Sheet_rev10.pdf



Charging the battery:

Charge the battery overnight. A fully charged battery will read 12-15VDC. The transponder will stop responding and its signal peak will disappear at around 5-6 volts. The battery voltage gradually drops in steps of 0.1-0.5 volts until it reaches 9 volts and then it will drop quickly to 5 volts in ~ 10 minutes. You can expect the transponder to work for 7.5 to 8 hours with a battery that is in good condition and fully charged.