Ok. Let’s try this again…RCA 9TC240 Alignment

[Penthode]

This is an interesting discussion! With stagger tuning you are not adjusting the four stages to one single frequency like in the FM stages or in an AM Radio. The stages are tuned to different frequencies or stagger tuned.

Simply put, stagger tuning is to stagger the frequencies each stage is tuned to. This is to provide the wideband needed to accommodate the wide bandwith video signal.

The stages are tuned to different frequencies so that the combination of the whole provides the over 4MHz bandwidth required.

Another point to understand and appreciate is the use of vestigial transmission for the video. For standard amplitude modulation (AM radio broadcast for example) both sidebands are transmitted. For television requiring 4MHz for the signal would require a 8MHz wide channel for both the AM sidebands. In the late 1930's it was discovered that if most of one of the sidebands was removed, a full resolution video could be delivered at the expense of slightly worsening the signal to noise performance of the transmission. So Vestigial Sideband is the sending only a "vestige" or portion of one of the sidebands.

How this relates to your alignment is the importance of placing the video carrier at exactly the 45% point of what is termed the "Nyquist Slope". Setting the carrier too high on the slope will emphasize the lower video frequencies in relation to the higher video frequencies. The higher video frequencies contain the fine detail in the displayed video. So improper carrier placement too high on the curve will make the picture less sharp and fuzzy. Conversely, the carrier too low on the curve will make the picture too sharp and edgy and make the picture noisy. Watching NTSC color signals on with the carrier too low will emphasize the subcarrier dots and destroy the image.

This you have to keep in mind when doing the sweep alignment.

We can discuss more closer to the time. Let's first get back to where we were and establish a baseline from which to begin the stagger tuned alignment.