Triplett CableRater- PN: 3279 - Manual (Page 16)

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typically use frequencies from about 40 Mega Hertz (MHz) to about 900MHz.
The CableRater performs tests at about 60MHz.
There are many resources ‘on line’ (on the Internet) that give details on the Loss
of various types of cables.
Figure 6 shows some typical Loss figures for RG-59 and RG-6. Notice that the
Loss at 60MHz for 100ft of RG-59 and RG-6 is about the same (2.4dB vs 2.1dB).
Figure 6 is only intended to be representative of coax in general. Different brands
of coax can have more or less Loss than shown in Figure 6.
Y C N E U Q E R F
9 5 - G R 6 - G R
t f 0 0 1 t f 0 0 2 t f 0 0 3 t f 0 0 1 t f 0 0 2 t f 0 0 3
z H M 0 6 B d 4 . 2 B d 8 . 4 B d 2 . 7 B d 1 . 2 B d 2 . 4 B d 3 . 6
z H M 0 0 9 B d 2 . 0 1 B d 4 . 0 2 B d 6 . 0 3 B d 3 . 9 B d 6 . 8 1 B d 9 . 7 2
Figure 6
Typical Cables Losses
So, you can expect about 2dB of Loss per 100 ft of cable or about 1dB for 50 ft.
or 4dB for 200 ft. Cables less than 50 ft long should have Losses of less than
1dB.
To check the Loss of a cable, first Calibrate the Transmitter as described in 9.4,
then connect one end of the cable to be tested to the Transmitter Output. and the
other end of the same cable to the Receiver Input (similar to Figure 5, but using
the cable you are testing instead of the patch cable). Press the ‘Meter’ button on
the Receiver and read the Loss on the LCD display. Loss is displayed as a nega-
tive or ‘minus’ value in dB.
Referring again to Figure 6, notice that the Loss at 900MHz is substantially greater
than at 60MHz. 900MHz is the frequency of cable TV channel 142. If the cable TV
distribution system being tested is expected to work at these frequencies, then
the 900MHz Loss is of great interest, and should be considered when designing
a system.
In general, most devices designed to work on a cable distribution system have a
relatively flat frequency response. That is, they exhibit about the same amount
(within a few dB) of Loss or Gain at all frequencies (that they are designed to
operate at).