View Single Post
  #38   Report Post  
Posted to sci.electronics.repair,rec.radio.amateur.antenna,sci.electronics.design
Joerg[_2_] Joerg[_2_] is offline
external usenet poster
 
Posts: 54
Default Increasing Cable TV signal strength

amdx wrote:
On 2/8/2012 7:50 PM, Joerg wrote:
amdx wrote:
On 2/8/2012 6:38 PM, Jeff Liebermann wrote:
On Wed, 08 Feb 2012 15:41:08 -0800, Jeff
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.

Any idea where channel 428 would be in that frequency range?
That's a duplicate of 4,2 but in HD, and it works when 42 doesn't.



I believe that's entirely up to the cable company, you'd have to ask an
engineer there.

http://en.wikipedia.org/wiki/Digital_cable

Quote "For example, a cable company might call channel 5-1 "channel 732"
and channel 5-2 "channel 733"".


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

Just a point. I may not have made it clear. I had the tech put in two
2way splitters and connect me to the first one. Hoping to gain 3db.
(or 4) and it did make a difference.


Where does the other leg of that splitter go to? And is that end
properly terminated?

[...]

They go to two other outlets, that are used for transient boaters.
sometimes they are used and sometimes they sit unterminated.
I have not seen my problem better or worse when boats are in or out.
But I have several 75 ohm F connector terminations. It's worth a try.



Yup, try it. Transient boaters will most likely not carry the required
set top box around but use the lower analog channels or nowadays maybe
UHF digital. Sort of "basic cable". Then the TV is connected directly
and those rarely have a true 75ohms input.

--
Regards, Joerg

http://www.analogconsultants.com/