IF Bandpass. The ideal Col-R-Tel TV set should have as wide an IF bandpass as possible. A wideband IF won't attenuate or degrade the color signal coming into the set. Sets with four IF amplifier tube stages are the best. A few models lend themselves extremely well. All these sets come from major manufacturers.

Video amplifier. Another consideration is the quality and bandpass of the set's video amplifier. The Col-R-Tel converter uses the TV's video amplifier to amplify the color signal. The video amp must have as wide a bandpass as possible. The video amp must also have high gain. The best video amplifier would have two stages.

Sets with intercarrier sound. Most sets of this era are intercarrier sets. Intercarrier sound circuits rely on both the video IF and video amplifier stages. These stages increase the 4.5 MHz sound carrier enough to drive audio detector circuitry. Intercarrier sets have a 4.5 MHz sound trap in the video signal path. The trap prevents the sound carrier from causing a herringbone moire pattern on the screen. Col-R-Tel also uses the video amplifier for signal amplification. To use Col-R-Tel, you must bypass, disconnect or at least detune the sound trap. Otherwise, it will severely degrade the 3.58 MHz color signal. This signal is less than 1 MHz from the sound IF frequency. One solution is to connect Col-R-Tel before the sound trap. For instance, feed Col-R-Tel from the plate of the last video amplifier tube. The idea is to get as much color signal to Col-R-Tel as possible.

Suitable brands. For Col-R-Tel use, many collectors seek Philco 50T-1100 or 50T-1400 series sets. At least one of these models has a 10-inch CRT. Most models have 12-inch screens. All have a four-stage video IF and a two-stage video amplifier. These sets make very crisp, detailed black-and-white pictures. To drive the Col-R-Tel converter chassis, the Philco sets have plenty of gain.