Re: Modulation and Digital Cable with Comcast

[Lewis Gardner <lgardner@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

tomvaldes@xxxxxxxxxxx wrote:
> I checked the diagnostics on my DCT2000 and also checked the digital
> channels that I watch.  It seems that of those channels, the highest
> frequency used by my digital channels is 741mHz (mostly HBO channels).
> If I use the LPF-750 would that leave the channels at the 741mHz
> intact? or is 741 too close to 750 that it would eat those channels?

I would be very hesitant to use a low pass filter on any signal that
feeds a digital cable box. The issue is that while truncating the
digital signal may work now, channel changes in the future may cause
problems. Digital cable sort of like satellite TV over a wire and with
the "dynamic" nature of channel line ups you cannot know when things
might change.

Two options:

1. Use a notch filter. Here is the ChannelPlus model:
http://www.channelplus.com/product_detail.php?productId=76
Custom notch filters are available for any frequency range from some
vendors like ChannelVision:
http://www.channelvision.com/index.php?exec=products.
Check items 3205/61-68, 3205/71-78 and 3102-Custom The idea is to remove
analog channels that you can get along without while leaving a "hole"
for your modulated channels. Unfortunately for you the stock filters
only allow inserting 3 channels.

2. Modulate the digital box(es) and keep your distribution system all
analog. Use a low pass filter in the wiring closet to remove the digital
signal prior to inserting the local modulated signals.