We are often asked:
"How long can the
cable
be from our Active Antennas to the Headend".
- Coax
cable has higher losses at
higher
frequencies and this is what is known as TILT~!
- This can
also be reffered to as "SLOPE" and needs to be
considered in any coaxial CATV cable run.
- Our
antennas have an internal amplifier that is designed
to compensate
for 100 ft or 30 meters of RG-6 cable.
- Tilt
compensation has been
applied in the
amplifier to boost the higher UHF signals so that when they reach the
head end
the levels are more or less equal. Longer
lengths will attenuate beyond the capabliity of the
amplifier. It is possible that weak
signals in the high
UHF band will be driven close or into the noise floor where they cannot
be
recoverd.
- The
amplifier also compensates equally for approximately 150
ft of
RG-11 Cable. For longer lengths, up to 200
ft use RF-213 or a cascadable tilt amplifier placed in
a critical
position on the string or branch.
- We
commonly supply 15dB Tilt
Amplifiers for
use on Navy ships to boost signals coming from a CATV shore source and
have a
long run across the pier and then to the Headend.
- Tilt or
Slope loss can also
affect video on video cables with long runs and thus reduces the
bandwidth or high frequency content of the video signal, which, in
turn, reduces the picture sharpness. At Satellite Baseband frequencies
the effect is very pronounced but the signal is relatively narrow band.
For runs greater than 150ft., fiber optics is often used.
Our
active
antennas are 75 ohms impedence normally but we can supply at 50 ohms
when
requested. It is mearly a small ferrite change in the internal
amplifier and a
different 50 ohm cable is used and of course a different connector. We
use F
connectors at 75 ohms and BNC connectors at 50 ohms.
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