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The early Hotpoint portable should be measured on second adjacent channel. All adjacent channel measurements should be 2 signal method with a modulated signal on the primary channel and continue to apply a second modulated signal on the adjacent (or second adjacent channel for older TVs) channel while watching (measuring) the measured channel for degradation. The difference in dB is the adjacent channel rejection characteristic for that receiver. For accuracy, there should be sound and color carriers as well. The result will vary widely from 2-13.
The original channel assignments left space between channels in the same markets. VHF was usually alternates. Four and five and 6/7 were exceptions due to band space between them. UHF was initially 6 channels apart. As cable became more popular, manufacturers had to improve selectivity so later TVs will perform much better on today's cable systems.
Last edited by Don Lindsly; 11-04-2010 at 01:14 PM.
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11-04-2010, 01:07 PM
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