RF Notch Filters

[Gene]

Hello,

I want to insert 6 modulated RF signals onto unused cable channels (between
80 & 100 or 105 to 125 ). If I understand correctly, the channels cleared
at mid-band of a notch filter will have less interference from surrounding
channels than those below or above the mid-band frequency. Are there other
considerations I should be aware of?

The notch filter works for both incoming and outgoing signals within its
range? Will the modulated signals be on the cable outside of my network?

Are there recommended vendors or brand names for these filters?

Thanks

[Ed Nielsen]

Take a look at the one at <http://www.cencom94.com/catalog9.4.html>. It
says for insertion above ch. 91, but you can start at 88 or 89. They
notch everything above 600MHz. Pretty much the same 50dB notch the full
bandwidth of the filter, which is 600-1000MHz. Unless you use
modulators designed for adjacent channel use, the modulated channels
need to be at least 2 channels apart. When combined properly utilizing
a directional coupler, your system is the only place they will be seen.

CIAO!

Ed Nielsen
CENCOM
http://www.cencom94.com

Post by Gene
Hello,
I want to insert 6 modulated RF signals onto unused cable channels (between
80 & 100 or 105 to 125 ). If I understand correctly, the channels cleared
at mid-band of a notch filter will have less interference from surrounding
channels than those below or above the mid-band frequency. Are there other
considerations I should be aware of?
The notch filter works for both incoming and outgoing signals within its
range? Will the modulated signals be on the cable outside of my network?
Are there recommended vendors or brand names for these filters?
Thanks

[Mike Rush]

Also, if you're talking about notch filters used by a cable company to block
a single channel at a customer's house, those filters usually only block the
actual video carrier so a TV's tuner can't lock onto the channel. They
usually allow a lot of the other signal through (color, sound, sideband,
etc.) and don't work well for removing a channel to substitute another.

Post by Ed Nielsen
Take a look at the one at <http://www.cencom94.com/catalog9.4.html>. It
says for insertion above ch. 91, but you can start at 88 or 89. They
notch everything above 600MHz. Pretty much the same 50dB notch the full
bandwidth of the filter, which is 600-1000MHz. Unless you use
modulators designed for adjacent channel use, the modulated channels
need to be at least 2 channels apart. When combined properly utilizing
a directional coupler, your system is the only place they will be seen.
CIAO!
Ed Nielsen
CENCOM
http://www.cencom94.com

Post by Gene
Hello,
I want to insert 6 modulated RF signals onto unused cable channels (between
80 & 100 or 105 to 125 ). If I understand correctly, the channels cleared
at mid-band of a notch filter will have less interference from surrounding
channels than those below or above the mid-band frequency. Are there other
considerations I should be aware of?
The notch filter works for both incoming and outgoing signals within its
range? Will the modulated signals be on the cable outside of my network?
Are there recommended vendors or brand names for these filters?
Thanks