[mythtv-users] Antenna wiring question

Craig Treleaven ctreleaven at cogeco.ca
Sat Nov 9 16:15:47 UTC 2013


At 9:12 AM -0600 11/9/13, Barry Martin wrote:
>After my Comcast bill went up $29 in one month, 
>I decided to start exploring alternatives.
>
>Don't blame you!  Did the same here.
>
>I have an antenna in the storage area (attic for 
>a story-and-a-half house) which goes to a 4-way 
>splitter to feed the three tuners to my 
>Mythbuntu Backend.  Use a 75‡ terminating 
>resistor on the unused splitter terminal.  I 
>also found I needed a pre-amp to boost the 
>signal strength.  Because the antenna farm is 
>only about 15 miles away I had to use a Winegard 
>HDP269 to minimize pixellation when the wind 
>blows and the signal strength suddenly 
>increases/decreases.  (Too much signal will 
>cause the AGC circuits to shut off.)

You need a pre-amp at 15 miles?!?  What antenna 
are you using; a rusty nail?  Perhaps the problem 
is that the antenna is indoors?  In general, you 
only get half the signal indoors compared to 
outdoors.  However, a steel roof or stucco siding 
can mean that only a tiny fraction of the signal 
makes it through.  (Think Faraday cage!)  See 
below regarding getting the signal from the 
antenna to where you want to use it.

>  The Mythbuntu Backend feeds the Mythbuntu Frontends via the Ethernet network.
>
>I originally wanted to also use the one antenna 
>to feed the various TVs for OTA.  Didn't quite 
>work!  If the TVs had sufficient signal that 
>overloaded the Mythbuntu Backend; proper signal 
>levels to the Backend was insufficient for the 
>TVs.  I tried various combinations of 
>amplifiers, attenuators.  Ended up getting a 
>second antenna to feed the TVs; that one also 
>needed a pre-amp due to the 8-way splitter. 
>(Not all TVs are on the Mythbuntu system.)

I wonder if the real problem is/was wiring.  For 
example, RG-59 has higher signal loss than RG-6 
for a given run.  Lots of other little problems 
can kill the signal on a branch.  Following link 
has some does and don't:

http://www.familyhandyman.com/electrical/wiring/tips-for-coaxial-cable-wiring/view-all

In the US, AntennaWeb is a pretty good resource 
for determining the recommended antenna type, etc:

http://www.antennaweb.org/

What I find funny is that homeowners in the 
1960's knew all about this kind of stuff.  When I 
was a kid, we had a big Yagi antenna on a 45' 
tower next the house with a rotator.  Two of the 
three channels we could get were at roughly 90 
degrees to each other and both were 50+ miles 
away.  Worked pretty darn reliably.

Craig


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