On Wed, 08 Feb 2012 15:41:08 -0800, Jeff Liebermann
wrote:

Your 200ft of RG6a/u will drop the signal from
between 4dB at the low end, to about 6dB at the high end.

Some better numbers for RG6a/u:
Freq Atten
MHz -dB
10 0.8
50 1.4
100 2.9
200 4.3
400 6.4
1000 11.0

The CATV band is approximately 50 to 800MHz. With 200ft of cable, you
should see 2.8 to 16dB of loss. While there may be problem at the
high channels, all the lower channels should work.

The 4 way splitter has a loss of about -7dB.

Picking a random set top box:
http://www.zoran.com/IMG/pdf/Simplify_NextGen_STBs_Solutions.pdf
See Page 3. Sensitivity is -18dBm for 256QAM and -24dBm 64QAM.

At the low end, you have 0dBm in, 7dB loss in the splitter, 2.8dB loss
in the coax, resulting in -9.8dBm to the box. That's much more than
the -18dBm/-24dBm needed.

However, at the high end, things are not so wonderful. 0dbm in, 7dB
loss in the splitter, and 16dB loss in the coax, which delivers
-23dBm. That's 1dB of margin, which is not very good. Still, it
should work on the lower channels.


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