The test antenna was set up in the garden in a clear area. With the aid of the selective field strength meter the new reference TV antenna was steered for minimum signal from the TV station. This was checked by plugging the cable into the TV set where a distorted and very week signal on channel 3 could just be seen. The field meter was then netted onto the fourth harmonic of 20 meters and 100 watt transmissions made from the main transceiver. No detectable signal could be measured. The TV monitor showed no interference.

Next the stations transmitting beam antenna was rotated without transmitting and the TV pictures level on the meter increase by 40 DB also the TV picture returned to normal viewing quality. It was established that the quad antenna side on to the TV station minimized both the field meter and TV signal. Directly facing or backsides on, produce a lift in signals. See TVi test set up drawing.

Conclusions are that the two element quad antenna is radiating a strong passive signal on TV channel 3 i.e. 56.8 Mhz. It is when the transmitter is activated and in a position of maximum TV picture strength that TVi occurs. It is noted that with adding many filters interposing as much as -160 db is without cure. Some other phenomenon is taking place to cause TVI At this point I have not had sufficient time to undertake additional investigation or cures for this effect.