[TenTec] OT Antenna Tuners plus one or 2 others

[Stuart Rohre]

Ten Tec T kits had a RF noise bridge designed as a Tuner Tuner.   This 
generates a wideband signal from a zener diode, and feeds it to a 50 ohm 
bridge, where you null the noise by adjusting your tuner.  When the noise is 
at null, the tuner is matched between the antenna and the standard 50 ohms 
in the bridge.  You disconnect this tuner aid, and connect your rig and you 
are all tuned up ready to transmit.

-Stuart Rohre
K5KVH