Cadco DC2000, Operating Manual

Page: 9 / 21

9
MGC Setup And Operation
If you are using the DC2000 for DOCSIS (cable modem). Return path operation uses it
should be operated in Manual Gain Control (MGC) only. Manual Gain Control is needed to
keep the DOCSIS (cable modem) from chasing the Automatic Gain Control (AGC).
If you are using the DC2000 for off-air or other antenna receive applications the MGC may
cause you to experience fluctuations in the output levels due to wind on the receive antenna
etc… Off-air using should be in AGC
not MGC.
To use the DC2000 for Manual Gain Control determine the signal input level from the input
signal source to the DC2000. Keep in mind that the output level of the DC2000 will be
reduced approximately by the difference from 0dBmV and the level of your input signal.
That is, if you have in input level of -10dBmV, the maximum output level from the DC2000
will be approximately
+15dBmV as measured from the top of the haystack
.
Switch the MGC switch on the back panel of the DC2000 to “ON.”
With a spectrum analyzer, look at the input source and notice the typical Input Signal.
See
Figure 0.0 (A minimum of 40dBmV from the top of the haystack to the noise floor
should be present for acceptable.)
Figure 0.0