Since distortions are created in an standard channel frequency format (or HRC, IRC depending on format), specific distortions will will always be there as a rule of thumb. If you have other "oddball" carriers (other than a standard NTSC frequency) persent in the spectrum, more beat products (other than the standard CTB and CSO beats) will be generated and show up in various places. This can happen if you have a STANDARD offset system (ch.2 = 55.25 MHz for example) and a HRC carrier(s) are also introduced in the headend (ch. 18 = 144.00 MHz for example) that would mix together and make a new (non-published in pocket guides) distortion.
In short, if you have any carriers in your headend that are not a normal NTSC offset being used, remove it/them to see if the problem is not being caused by that if all else is in good shape.
I had this type problem in California back in 1986-87 when we had a system that was HRC and used a STANDARD offset Dixhills to fill in the missing channels. It produced an entire new beat product that was easily seen at the 3-4th anp out and got progressively worse as the cascade deepened.
Good Luck!
Greg Tobin
(-REDACTED-)
(314) 422-4423 cel
Re: Beat Problem; another possibility
Member #: 7190
Registered: 1996-2001
Posted:
483
Name:
Greg Tobin
Name:
Greg Tobin
Company:
Interactive Broadband Technical Services
Occupation:
HFC Engineer/Consultant
Location:
www.interactive-broadband.com
Personal:
Experience:
~45 years
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